| /*P:100 |
| * This is the Launcher code, a simple program which lays out the "physical" |
| * memory for the new Guest by mapping the kernel image and the virtual |
| * devices, then opens /dev/lguest to tell the kernel about the Guest and |
| * control it. |
| :*/ |
| #define _LARGEFILE64_SOURCE |
| #define _GNU_SOURCE |
| #include <stdio.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <err.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <elf.h> |
| #include <sys/mman.h> |
| #include <sys/param.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <sys/wait.h> |
| #include <sys/eventfd.h> |
| #include <fcntl.h> |
| #include <stdbool.h> |
| #include <errno.h> |
| #include <ctype.h> |
| #include <sys/socket.h> |
| #include <sys/ioctl.h> |
| #include <sys/time.h> |
| #include <time.h> |
| #include <netinet/in.h> |
| #include <net/if.h> |
| #include <linux/sockios.h> |
| #include <linux/if_tun.h> |
| #include <sys/uio.h> |
| #include <termios.h> |
| #include <getopt.h> |
| #include <assert.h> |
| #include <sched.h> |
| #include <limits.h> |
| #include <stddef.h> |
| #include <signal.h> |
| #include <pwd.h> |
| #include <grp.h> |
| #include <sys/user.h> |
| #include <linux/pci_regs.h> |
| |
| #ifndef VIRTIO_F_ANY_LAYOUT |
| #define VIRTIO_F_ANY_LAYOUT 27 |
| #endif |
| |
| /*L:110 |
| * We can ignore the 43 include files we need for this program, but I do want |
| * to draw attention to the use of kernel-style types. |
| * |
| * As Linus said, "C is a Spartan language, and so should your naming be." I |
| * like these abbreviations, so we define them here. Note that u64 is always |
| * unsigned long long, which works on all Linux systems: this means that we can |
| * use %llu in printf for any u64. |
| */ |
| typedef unsigned long long u64; |
| typedef uint32_t u32; |
| typedef uint16_t u16; |
| typedef uint8_t u8; |
| /*:*/ |
| |
| #define VIRTIO_CONFIG_NO_LEGACY |
| #define VIRTIO_PCI_NO_LEGACY |
| #define VIRTIO_BLK_NO_LEGACY |
| #define VIRTIO_NET_NO_LEGACY |
| |
| /* Use in-kernel ones, which defines VIRTIO_F_VERSION_1 */ |
| #include "../../include/uapi/linux/virtio_config.h" |
| #include "../../include/uapi/linux/virtio_net.h" |
| #include "../../include/uapi/linux/virtio_blk.h" |
| #include "../../include/uapi/linux/virtio_console.h" |
| #include "../../include/uapi/linux/virtio_rng.h" |
| #include <linux/virtio_ring.h> |
| #include "../../include/uapi/linux/virtio_pci.h" |
| #include <asm/bootparam.h> |
| #include "../../include/linux/lguest_launcher.h" |
| |
| #define BRIDGE_PFX "bridge:" |
| #ifndef SIOCBRADDIF |
| #define SIOCBRADDIF 0x89a2 /* add interface to bridge */ |
| #endif |
| /* We can have up to 256 pages for devices. */ |
| #define DEVICE_PAGES 256 |
| /* This will occupy 3 pages: it must be a power of 2. */ |
| #define VIRTQUEUE_NUM 256 |
| |
| /*L:120 |
| * verbose is both a global flag and a macro. The C preprocessor allows |
| * this, and although I wouldn't recommend it, it works quite nicely here. |
| */ |
| static bool verbose; |
| #define verbose(args...) \ |
| do { if (verbose) printf(args); } while(0) |
| /*:*/ |
| |
| /* The pointer to the start of guest memory. */ |
| static void *guest_base; |
| /* The maximum guest physical address allowed, and maximum possible. */ |
| static unsigned long guest_limit, guest_max, guest_mmio; |
| /* The /dev/lguest file descriptor. */ |
| static int lguest_fd; |
| |
| /* a per-cpu variable indicating whose vcpu is currently running */ |
| static unsigned int __thread cpu_id; |
| |
| /* 5 bit device number in the PCI_CONFIG_ADDR => 32 only */ |
| #define MAX_PCI_DEVICES 32 |
| |
| /* This is our list of devices. */ |
| struct device_list { |
| /* Counter to assign interrupt numbers. */ |
| unsigned int next_irq; |
| |
| /* Counter to print out convenient device numbers. */ |
| unsigned int device_num; |
| |
| /* PCI devices. */ |
| struct device *pci[MAX_PCI_DEVICES]; |
| }; |
| |
| /* The list of Guest devices, based on command line arguments. */ |
| static struct device_list devices; |
| |
| /* |
| * Just like struct virtio_pci_cfg_cap in uapi/linux/virtio_pci.h, |
| * but uses a u32 explicitly for the data. |
| */ |
| struct virtio_pci_cfg_cap_u32 { |
| struct virtio_pci_cap cap; |
| u32 pci_cfg_data; /* Data for BAR access. */ |
| }; |
| |
| struct virtio_pci_mmio { |
| struct virtio_pci_common_cfg cfg; |
| u16 notify; |
| u8 isr; |
| u8 padding; |
| /* Device-specific configuration follows this. */ |
| }; |
| |
| /* This is the layout (little-endian) of the PCI config space. */ |
| struct pci_config { |
| u16 vendor_id, device_id; |
| u16 command, status; |
| u8 revid, prog_if, subclass, class; |
| u8 cacheline_size, lat_timer, header_type, bist; |
| u32 bar[6]; |
| u32 cardbus_cis_ptr; |
| u16 subsystem_vendor_id, subsystem_device_id; |
| u32 expansion_rom_addr; |
| u8 capabilities, reserved1[3]; |
| u32 reserved2; |
| u8 irq_line, irq_pin, min_grant, max_latency; |
| |
| /* Now, this is the linked capability list. */ |
| struct virtio_pci_cap common; |
| struct virtio_pci_notify_cap notify; |
| struct virtio_pci_cap isr; |
| struct virtio_pci_cap device; |
| struct virtio_pci_cfg_cap_u32 cfg_access; |
| }; |
| |
| /* The device structure describes a single device. */ |
| struct device { |
| /* The name of this device, for --verbose. */ |
| const char *name; |
| |
| /* Any queues attached to this device */ |
| struct virtqueue *vq; |
| |
| /* Is it operational */ |
| bool running; |
| |
| /* Has it written FEATURES_OK but not re-checked it? */ |
| bool wrote_features_ok; |
| |
| /* PCI configuration */ |
| union { |
| struct pci_config config; |
| u32 config_words[sizeof(struct pci_config) / sizeof(u32)]; |
| }; |
| |
| /* Features we offer, and those accepted. */ |
| u64 features, features_accepted; |
| |
| /* Device-specific config hangs off the end of this. */ |
| struct virtio_pci_mmio *mmio; |
| |
| /* PCI MMIO resources (all in BAR0) */ |
| size_t mmio_size; |
| u32 mmio_addr; |
| |
| /* Device-specific data. */ |
| void *priv; |
| }; |
| |
| /* The virtqueue structure describes a queue attached to a device. */ |
| struct virtqueue { |
| struct virtqueue *next; |
| |
| /* Which device owns me. */ |
| struct device *dev; |
| |
| /* Name for printing errors. */ |
| const char *name; |
| |
| /* The actual ring of buffers. */ |
| struct vring vring; |
| |
| /* The information about this virtqueue (we only use queue_size on) */ |
| struct virtio_pci_common_cfg pci_config; |
| |
| /* Last available index we saw. */ |
| u16 last_avail_idx; |
| |
| /* How many are used since we sent last irq? */ |
| unsigned int pending_used; |
| |
| /* Eventfd where Guest notifications arrive. */ |
| int eventfd; |
| |
| /* Function for the thread which is servicing this virtqueue. */ |
| void (*service)(struct virtqueue *vq); |
| pid_t thread; |
| }; |
| |
| /* Remember the arguments to the program so we can "reboot" */ |
| static char **main_args; |
| |
| /* The original tty settings to restore on exit. */ |
| static struct termios orig_term; |
| |
| /* |
| * We have to be careful with barriers: our devices are all run in separate |
| * threads and so we need to make sure that changes visible to the Guest happen |
| * in precise order. |
| */ |
| #define wmb() __asm__ __volatile__("" : : : "memory") |
| #define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory") |
| #define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory") |
| |
| /* Wrapper for the last available index. Makes it easier to change. */ |
| #define lg_last_avail(vq) ((vq)->last_avail_idx) |
| |
| /* |
| * The virtio configuration space is defined to be little-endian. x86 is |
| * little-endian too, but it's nice to be explicit so we have these helpers. |
| */ |
| #define cpu_to_le16(v16) (v16) |
| #define cpu_to_le32(v32) (v32) |
| #define cpu_to_le64(v64) (v64) |
| #define le16_to_cpu(v16) (v16) |
| #define le32_to_cpu(v32) (v32) |
| #define le64_to_cpu(v64) (v64) |
| |
| /* |
| * A real device would ignore weird/non-compliant driver behaviour. We |
| * stop and flag it, to help debugging Linux problems. |
| */ |
| #define bad_driver(d, fmt, ...) \ |
| errx(1, "%s: bad driver: " fmt, (d)->name, ## __VA_ARGS__) |
| #define bad_driver_vq(vq, fmt, ...) \ |
| errx(1, "%s vq %s: bad driver: " fmt, (vq)->dev->name, \ |
| vq->name, ## __VA_ARGS__) |
| |
| /* Is this iovec empty? */ |
| static bool iov_empty(const struct iovec iov[], unsigned int num_iov) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < num_iov; i++) |
| if (iov[i].iov_len) |
| return false; |
| return true; |
| } |
| |
| /* Take len bytes from the front of this iovec. */ |
| static void iov_consume(struct device *d, |
| struct iovec iov[], unsigned num_iov, |
| void *dest, unsigned len) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < num_iov; i++) { |
| unsigned int used; |
| |
| used = iov[i].iov_len < len ? iov[i].iov_len : len; |
| if (dest) { |
| memcpy(dest, iov[i].iov_base, used); |
| dest += used; |
| } |
| iov[i].iov_base += used; |
| iov[i].iov_len -= used; |
| len -= used; |
| } |
| if (len != 0) |
| bad_driver(d, "iovec too short!"); |
| } |
| |
| /*L:100 |
| * The Launcher code itself takes us out into userspace, that scary place where |
| * pointers run wild and free! Unfortunately, like most userspace programs, |
| * it's quite boring (which is why everyone likes to hack on the kernel!). |
| * Perhaps if you make up an Lguest Drinking Game at this point, it will get |
| * you through this section. Or, maybe not. |
| * |
| * The Launcher sets up a big chunk of memory to be the Guest's "physical" |
| * memory and stores it in "guest_base". In other words, Guest physical == |
| * Launcher virtual with an offset. |
| * |
| * This can be tough to get your head around, but usually it just means that we |
| * use these trivial conversion functions when the Guest gives us its |
| * "physical" addresses: |
| */ |
| static void *from_guest_phys(unsigned long addr) |
| { |
| return guest_base + addr; |
| } |
| |
| static unsigned long to_guest_phys(const void *addr) |
| { |
| return (addr - guest_base); |
| } |
| |
| /*L:130 |
| * Loading the Kernel. |
| * |
| * We start with couple of simple helper routines. open_or_die() avoids |
| * error-checking code cluttering the callers: |
| */ |
| static int open_or_die(const char *name, int flags) |
| { |
| int fd = open(name, flags); |
| if (fd < 0) |
| err(1, "Failed to open %s", name); |
| return fd; |
| } |
| |
| /* map_zeroed_pages() takes a number of pages. */ |
| static void *map_zeroed_pages(unsigned int num) |
| { |
| int fd = open_or_die("/dev/zero", O_RDONLY); |
| void *addr; |
| |
| /* |
| * We use a private mapping (ie. if we write to the page, it will be |
| * copied). We allocate an extra two pages PROT_NONE to act as guard |
| * pages against read/write attempts that exceed allocated space. |
| */ |
| addr = mmap(NULL, getpagesize() * (num+2), |
| PROT_NONE, MAP_PRIVATE, fd, 0); |
| |
| if (addr == MAP_FAILED) |
| err(1, "Mmapping %u pages of /dev/zero", num); |
| |
| if (mprotect(addr + getpagesize(), getpagesize() * num, |
| PROT_READ|PROT_WRITE) == -1) |
| err(1, "mprotect rw %u pages failed", num); |
| |
| /* |
| * One neat mmap feature is that you can close the fd, and it |
| * stays mapped. |
| */ |
| close(fd); |
| |
| /* Return address after PROT_NONE page */ |
| return addr + getpagesize(); |
| } |
| |
| /* Get some bytes which won't be mapped into the guest. */ |
| static unsigned long get_mmio_region(size_t size) |
| { |
| unsigned long addr = guest_mmio; |
| size_t i; |
| |
| if (!size) |
| return addr; |
| |
| /* Size has to be a power of 2 (and multiple of 16) */ |
| for (i = 1; i < size; i <<= 1); |
| |
| guest_mmio += i; |
| |
| return addr; |
| } |
| |
| /* |
| * This routine is used to load the kernel or initrd. It tries mmap, but if |
| * that fails (Plan 9's kernel file isn't nicely aligned on page boundaries), |
| * it falls back to reading the memory in. |
| */ |
| static void map_at(int fd, void *addr, unsigned long offset, unsigned long len) |
| { |
| ssize_t r; |
| |
| /* |
| * We map writable even though for some segments are marked read-only. |
| * The kernel really wants to be writable: it patches its own |
| * instructions. |
| * |
| * MAP_PRIVATE means that the page won't be copied until a write is |
| * done to it. This allows us to share untouched memory between |
| * Guests. |
| */ |
| if (mmap(addr, len, PROT_READ|PROT_WRITE, |
| MAP_FIXED|MAP_PRIVATE, fd, offset) != MAP_FAILED) |
| return; |
| |
| /* pread does a seek and a read in one shot: saves a few lines. */ |
| r = pread(fd, addr, len, offset); |
| if (r != len) |
| err(1, "Reading offset %lu len %lu gave %zi", offset, len, r); |
| } |
| |
| /* |
| * This routine takes an open vmlinux image, which is in ELF, and maps it into |
| * the Guest memory. ELF = Embedded Linking Format, which is the format used |
| * by all modern binaries on Linux including the kernel. |
| * |
| * The ELF headers give *two* addresses: a physical address, and a virtual |
| * address. We use the physical address; the Guest will map itself to the |
| * virtual address. |
| * |
| * We return the starting address. |
| */ |
| static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr) |
| { |
| Elf32_Phdr phdr[ehdr->e_phnum]; |
| unsigned int i; |
| |
| /* |
| * Sanity checks on the main ELF header: an x86 executable with a |
| * reasonable number of correctly-sized program headers. |
| */ |
| if (ehdr->e_type != ET_EXEC |
| || ehdr->e_machine != EM_386 |
| || ehdr->e_phentsize != sizeof(Elf32_Phdr) |
| || ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr)) |
| errx(1, "Malformed elf header"); |
| |
| /* |
| * An ELF executable contains an ELF header and a number of "program" |
| * headers which indicate which parts ("segments") of the program to |
| * load where. |
| */ |
| |
| /* We read in all the program headers at once: */ |
| if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0) |
| err(1, "Seeking to program headers"); |
| if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr)) |
| err(1, "Reading program headers"); |
| |
| /* |
| * Try all the headers: there are usually only three. A read-only one, |
| * a read-write one, and a "note" section which we don't load. |
| */ |
| for (i = 0; i < ehdr->e_phnum; i++) { |
| /* If this isn't a loadable segment, we ignore it */ |
| if (phdr[i].p_type != PT_LOAD) |
| continue; |
| |
| verbose("Section %i: size %i addr %p\n", |
| i, phdr[i].p_memsz, (void *)phdr[i].p_paddr); |
| |
| /* We map this section of the file at its physical address. */ |
| map_at(elf_fd, from_guest_phys(phdr[i].p_paddr), |
| phdr[i].p_offset, phdr[i].p_filesz); |
| } |
| |
| /* The entry point is given in the ELF header. */ |
| return ehdr->e_entry; |
| } |
| |
| /*L:150 |
| * A bzImage, unlike an ELF file, is not meant to be loaded. You're supposed |
| * to jump into it and it will unpack itself. We used to have to perform some |
| * hairy magic because the unpacking code scared me. |
| * |
| * Fortunately, Jeremy Fitzhardinge convinced me it wasn't that hard and wrote |
| * a small patch to jump over the tricky bits in the Guest, so now we just read |
| * the funky header so we know where in the file to load, and away we go! |
| */ |
| static unsigned long load_bzimage(int fd) |
| { |
| struct boot_params boot; |
| int r; |
| /* Modern bzImages get loaded at 1M. */ |
| void *p = from_guest_phys(0x100000); |
| |
| /* |
| * Go back to the start of the file and read the header. It should be |
| * a Linux boot header (see Documentation/x86/boot.txt) |
| */ |
| lseek(fd, 0, SEEK_SET); |
| read(fd, &boot, sizeof(boot)); |
| |
| /* Inside the setup_hdr, we expect the magic "HdrS" */ |
| if (memcmp(&boot.hdr.header, "HdrS", 4) != 0) |
| errx(1, "This doesn't look like a bzImage to me"); |
| |
| /* Skip over the extra sectors of the header. */ |
| lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET); |
| |
| /* Now read everything into memory. in nice big chunks. */ |
| while ((r = read(fd, p, 65536)) > 0) |
| p += r; |
| |
| /* Finally, code32_start tells us where to enter the kernel. */ |
| return boot.hdr.code32_start; |
| } |
| |
| /*L:140 |
| * Loading the kernel is easy when it's a "vmlinux", but most kernels |
| * come wrapped up in the self-decompressing "bzImage" format. With a little |
| * work, we can load those, too. |
| */ |
| static unsigned long load_kernel(int fd) |
| { |
| Elf32_Ehdr hdr; |
| |
| /* Read in the first few bytes. */ |
| if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) |
| err(1, "Reading kernel"); |
| |
| /* If it's an ELF file, it starts with "\177ELF" */ |
| if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0) |
| return map_elf(fd, &hdr); |
| |
| /* Otherwise we assume it's a bzImage, and try to load it. */ |
| return load_bzimage(fd); |
| } |
| |
| /* |
| * This is a trivial little helper to align pages. Andi Kleen hated it because |
| * it calls getpagesize() twice: "it's dumb code." |
| * |
| * Kernel guys get really het up about optimization, even when it's not |
| * necessary. I leave this code as a reaction against that. |
| */ |
| static inline unsigned long page_align(unsigned long addr) |
| { |
| /* Add upwards and truncate downwards. */ |
| return ((addr + getpagesize()-1) & ~(getpagesize()-1)); |
| } |
| |
| /*L:180 |
| * An "initial ram disk" is a disk image loaded into memory along with the |
| * kernel which the kernel can use to boot from without needing any drivers. |
| * Most distributions now use this as standard: the initrd contains the code to |
| * load the appropriate driver modules for the current machine. |
| * |
| * Importantly, James Morris works for RedHat, and Fedora uses initrds for its |
| * kernels. He sent me this (and tells me when I break it). |
| */ |
| static unsigned long load_initrd(const char *name, unsigned long mem) |
| { |
| int ifd; |
| struct stat st; |
| unsigned long len; |
| |
| ifd = open_or_die(name, O_RDONLY); |
| /* fstat() is needed to get the file size. */ |
| if (fstat(ifd, &st) < 0) |
| err(1, "fstat() on initrd '%s'", name); |
| |
| /* |
| * We map the initrd at the top of memory, but mmap wants it to be |
| * page-aligned, so we round the size up for that. |
| */ |
| len = page_align(st.st_size); |
| map_at(ifd, from_guest_phys(mem - len), 0, st.st_size); |
| /* |
| * Once a file is mapped, you can close the file descriptor. It's a |
| * little odd, but quite useful. |
| */ |
| close(ifd); |
| verbose("mapped initrd %s size=%lu @ %p\n", name, len, (void*)mem-len); |
| |
| /* We return the initrd size. */ |
| return len; |
| } |
| /*:*/ |
| |
| /* |
| * Simple routine to roll all the commandline arguments together with spaces |
| * between them. |
| */ |
| static void concat(char *dst, char *args[]) |
| { |
| unsigned int i, len = 0; |
| |
| for (i = 0; args[i]; i++) { |
| if (i) { |
| strcat(dst+len, " "); |
| len++; |
| } |
| strcpy(dst+len, args[i]); |
| len += strlen(args[i]); |
| } |
| /* In case it's empty. */ |
| dst[len] = '\0'; |
| } |
| |
| /*L:185 |
| * This is where we actually tell the kernel to initialize the Guest. We |
| * saw the arguments it expects when we looked at initialize() in lguest_user.c: |
| * the base of Guest "physical" memory, the top physical page to allow and the |
| * entry point for the Guest. |
| */ |
| static void tell_kernel(unsigned long start) |
| { |
| unsigned long args[] = { LHREQ_INITIALIZE, |
| (unsigned long)guest_base, |
| guest_limit / getpagesize(), start, |
| (guest_mmio+getpagesize()-1) / getpagesize() }; |
| verbose("Guest: %p - %p (%#lx, MMIO %#lx)\n", |
| guest_base, guest_base + guest_limit, |
| guest_limit, guest_mmio); |
| lguest_fd = open_or_die("/dev/lguest", O_RDWR); |
| if (write(lguest_fd, args, sizeof(args)) < 0) |
| err(1, "Writing to /dev/lguest"); |
| } |
| /*:*/ |
| |
| /*L:200 |
| * Device Handling. |
| * |
| * When the Guest gives us a buffer, it sends an array of addresses and sizes. |
| * We need to make sure it's not trying to reach into the Launcher itself, so |
| * we have a convenient routine which checks it and exits with an error message |
| * if something funny is going on: |
| */ |
| static void *_check_pointer(struct device *d, |
| unsigned long addr, unsigned int size, |
| unsigned int line) |
| { |
| /* |
| * Check if the requested address and size exceeds the allocated memory, |
| * or addr + size wraps around. |
| */ |
| if ((addr + size) > guest_limit || (addr + size) < addr) |
| bad_driver(d, "%s:%i: Invalid address %#lx", |
| __FILE__, line, addr); |
| /* |
| * We return a pointer for the caller's convenience, now we know it's |
| * safe to use. |
| */ |
| return from_guest_phys(addr); |
| } |
| /* A macro which transparently hands the line number to the real function. */ |
| #define check_pointer(d,addr,size) _check_pointer(d, addr, size, __LINE__) |
| |
| /* |
| * Each buffer in the virtqueues is actually a chain of descriptors. This |
| * function returns the next descriptor in the chain, or vq->vring.num if we're |
| * at the end. |
| */ |
| static unsigned next_desc(struct device *d, struct vring_desc *desc, |
| unsigned int i, unsigned int max) |
| { |
| unsigned int next; |
| |
| /* If this descriptor says it doesn't chain, we're done. */ |
| if (!(desc[i].flags & VRING_DESC_F_NEXT)) |
| return max; |
| |
| /* Check they're not leading us off end of descriptors. */ |
| next = desc[i].next; |
| /* Make sure compiler knows to grab that: we don't want it changing! */ |
| wmb(); |
| |
| if (next >= max) |
| bad_driver(d, "Desc next is %u", next); |
| |
| return next; |
| } |
| |
| /* |
| * This actually sends the interrupt for this virtqueue, if we've used a |
| * buffer. |
| */ |
| static void trigger_irq(struct virtqueue *vq) |
| { |
| unsigned long buf[] = { LHREQ_IRQ, vq->dev->config.irq_line }; |
| |
| /* Don't inform them if nothing used. */ |
| if (!vq->pending_used) |
| return; |
| vq->pending_used = 0; |
| |
| /* |
| * 2.4.7.1: |
| * |
| * If the VIRTIO_F_EVENT_IDX feature bit is not negotiated: |
| * The driver MUST set flags to 0 or 1. |
| */ |
| if (vq->vring.avail->flags > 1) |
| bad_driver_vq(vq, "avail->flags = %u\n", vq->vring.avail->flags); |
| |
| /* |
| * 2.4.7.2: |
| * |
| * If the VIRTIO_F_EVENT_IDX feature bit is not negotiated: |
| * |
| * - The device MUST ignore the used_event value. |
| * - After the device writes a descriptor index into the used ring: |
| * - If flags is 1, the device SHOULD NOT send an interrupt. |
| * - If flags is 0, the device MUST send an interrupt. |
| */ |
| if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) { |
| return; |
| } |
| |
| /* |
| * 4.1.4.5.1: |
| * |
| * If MSI-X capability is disabled, the device MUST set the Queue |
| * Interrupt bit in ISR status before sending a virtqueue notification |
| * to the driver. |
| */ |
| vq->dev->mmio->isr = 0x1; |
| |
| /* Send the Guest an interrupt tell them we used something up. */ |
| if (write(lguest_fd, buf, sizeof(buf)) != 0) |
| err(1, "Triggering irq %i", vq->dev->config.irq_line); |
| } |
| |
| /* |
| * This looks in the virtqueue for the first available buffer, and converts |
| * it to an iovec for convenient access. Since descriptors consist of some |
| * number of output then some number of input descriptors, it's actually two |
| * iovecs, but we pack them into one and note how many of each there were. |
| * |
| * This function waits if necessary, and returns the descriptor number found. |
| */ |
| static unsigned wait_for_vq_desc(struct virtqueue *vq, |
| struct iovec iov[], |
| unsigned int *out_num, unsigned int *in_num) |
| { |
| unsigned int i, head, max; |
| struct vring_desc *desc; |
| u16 last_avail = lg_last_avail(vq); |
| |
| /* |
| * 2.4.7.1: |
| * |
| * The driver MUST handle spurious interrupts from the device. |
| * |
| * That's why this is a while loop. |
| */ |
| |
| /* There's nothing available? */ |
| while (last_avail == vq->vring.avail->idx) { |
| u64 event; |
| |
| /* |
| * Since we're about to sleep, now is a good time to tell the |
| * Guest about what we've used up to now. |
| */ |
| trigger_irq(vq); |
| |
| /* OK, now we need to know about added descriptors. */ |
| vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY; |
| |
| /* |
| * They could have slipped one in as we were doing that: make |
| * sure it's written, then check again. |
| */ |
| mb(); |
| if (last_avail != vq->vring.avail->idx) { |
| vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY; |
| break; |
| } |
| |
| /* Nothing new? Wait for eventfd to tell us they refilled. */ |
| if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event)) |
| errx(1, "Event read failed?"); |
| |
| /* We don't need to be notified again. */ |
| vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY; |
| } |
| |
| /* Check it isn't doing very strange things with descriptor numbers. */ |
| if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num) |
| bad_driver_vq(vq, "Guest moved used index from %u to %u", |
| last_avail, vq->vring.avail->idx); |
| |
| /* |
| * Make sure we read the descriptor number *after* we read the ring |
| * update; don't let the cpu or compiler change the order. |
| */ |
| rmb(); |
| |
| /* |
| * Grab the next descriptor number they're advertising, and increment |
| * the index we've seen. |
| */ |
| head = vq->vring.avail->ring[last_avail % vq->vring.num]; |
| lg_last_avail(vq)++; |
| |
| /* If their number is silly, that's a fatal mistake. */ |
| if (head >= vq->vring.num) |
| bad_driver_vq(vq, "Guest says index %u is available", head); |
| |
| /* When we start there are none of either input nor output. */ |
| *out_num = *in_num = 0; |
| |
| max = vq->vring.num; |
| desc = vq->vring.desc; |
| i = head; |
| |
| /* |
| * We have to read the descriptor after we read the descriptor number, |
| * but there's a data dependency there so the CPU shouldn't reorder |
| * that: no rmb() required. |
| */ |
| |
| do { |
| /* |
| * If this is an indirect entry, then this buffer contains a |
| * descriptor table which we handle as if it's any normal |
| * descriptor chain. |
| */ |
| if (desc[i].flags & VRING_DESC_F_INDIRECT) { |
| /* 2.4.5.3.1: |
| * |
| * The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT |
| * flag unless the VIRTIO_F_INDIRECT_DESC feature was |
| * negotiated. |
| */ |
| if (!(vq->dev->features_accepted & |
| (1<<VIRTIO_RING_F_INDIRECT_DESC))) |
| bad_driver_vq(vq, "vq indirect not negotiated"); |
| |
| /* |
| * 2.4.5.3.1: |
| * |
| * The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT |
| * flag within an indirect descriptor (ie. only one |
| * table per descriptor). |
| */ |
| if (desc != vq->vring.desc) |
| bad_driver_vq(vq, "Indirect within indirect"); |
| |
| /* |
| * Proposed update VIRTIO-134 spells this out: |
| * |
| * A driver MUST NOT set both VIRTQ_DESC_F_INDIRECT |
| * and VIRTQ_DESC_F_NEXT in flags. |
| */ |
| if (desc[i].flags & VRING_DESC_F_NEXT) |
| bad_driver_vq(vq, "indirect and next together"); |
| |
| if (desc[i].len % sizeof(struct vring_desc)) |
| bad_driver_vq(vq, |
| "Invalid size for indirect table"); |
| /* |
| * 2.4.5.3.2: |
| * |
| * The device MUST ignore the write-only flag |
| * (flags&VIRTQ_DESC_F_WRITE) in the descriptor that |
| * refers to an indirect table. |
| * |
| * We ignore it here: :) |
| */ |
| |
| max = desc[i].len / sizeof(struct vring_desc); |
| desc = check_pointer(vq->dev, desc[i].addr, desc[i].len); |
| i = 0; |
| |
| /* 2.4.5.3.1: |
| * |
| * A driver MUST NOT create a descriptor chain longer |
| * than the Queue Size of the device. |
| */ |
| if (max > vq->pci_config.queue_size) |
| bad_driver_vq(vq, |
| "indirect has too many entries"); |
| } |
| |
| /* Grab the first descriptor, and check it's OK. */ |
| iov[*out_num + *in_num].iov_len = desc[i].len; |
| iov[*out_num + *in_num].iov_base |
| = check_pointer(vq->dev, desc[i].addr, desc[i].len); |
| /* If this is an input descriptor, increment that count. */ |
| if (desc[i].flags & VRING_DESC_F_WRITE) |
| (*in_num)++; |
| else { |
| /* |
| * If it's an output descriptor, they're all supposed |
| * to come before any input descriptors. |
| */ |
| if (*in_num) |
| bad_driver_vq(vq, |
| "Descriptor has out after in"); |
| (*out_num)++; |
| } |
| |
| /* If we've got too many, that implies a descriptor loop. */ |
| if (*out_num + *in_num > max) |
| bad_driver_vq(vq, "Looped descriptor"); |
| } while ((i = next_desc(vq->dev, desc, i, max)) != max); |
| |
| return head; |
| } |
| |
| /* |
| * After we've used one of their buffers, we tell the Guest about it. Sometime |
| * later we'll want to send them an interrupt using trigger_irq(); note that |
| * wait_for_vq_desc() does that for us if it has to wait. |
| */ |
| static void add_used(struct virtqueue *vq, unsigned int head, int len) |
| { |
| struct vring_used_elem *used; |
| |
| /* |
| * The virtqueue contains a ring of used buffers. Get a pointer to the |
| * next entry in that used ring. |
| */ |
| used = &vq->vring.used->ring[vq->vring.used->idx % vq->vring.num]; |
| used->id = head; |
| used->len = len; |
| /* Make sure buffer is written before we update index. */ |
| wmb(); |
| vq->vring.used->idx++; |
| vq->pending_used++; |
| } |
| |
| /* And here's the combo meal deal. Supersize me! */ |
| static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len) |
| { |
| add_used(vq, head, len); |
| trigger_irq(vq); |
| } |
| |
| /* |
| * The Console |
| * |
| * We associate some data with the console for our exit hack. |
| */ |
| struct console_abort { |
| /* How many times have they hit ^C? */ |
| int count; |
| /* When did they start? */ |
| struct timeval start; |
| }; |
| |
| /* This is the routine which handles console input (ie. stdin). */ |
| static void console_input(struct virtqueue *vq) |
| { |
| int len; |
| unsigned int head, in_num, out_num; |
| struct console_abort *abort = vq->dev->priv; |
| struct iovec iov[vq->vring.num]; |
| |
| /* Make sure there's a descriptor available. */ |
| head = wait_for_vq_desc(vq, iov, &out_num, &in_num); |
| if (out_num) |
| bad_driver_vq(vq, "Output buffers in console in queue?"); |
| |
| /* Read into it. This is where we usually wait. */ |
| len = readv(STDIN_FILENO, iov, in_num); |
| if (len <= 0) { |
| /* Ran out of input? */ |
| warnx("Failed to get console input, ignoring console."); |
| /* |
| * For simplicity, dying threads kill the whole Launcher. So |
| * just nap here. |
| */ |
| for (;;) |
| pause(); |
| } |
| |
| /* Tell the Guest we used a buffer. */ |
| add_used_and_trigger(vq, head, len); |
| |
| /* |
| * Three ^C within one second? Exit. |
| * |
| * This is such a hack, but works surprisingly well. Each ^C has to |
| * be in a buffer by itself, so they can't be too fast. But we check |
| * that we get three within about a second, so they can't be too |
| * slow. |
| */ |
| if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) { |
| abort->count = 0; |
| return; |
| } |
| |
| abort->count++; |
| if (abort->count == 1) |
| gettimeofday(&abort->start, NULL); |
| else if (abort->count == 3) { |
| struct timeval now; |
| gettimeofday(&now, NULL); |
| /* Kill all Launcher processes with SIGINT, like normal ^C */ |
| if (now.tv_sec <= abort->start.tv_sec+1) |
| kill(0, SIGINT); |
| abort->count = 0; |
| } |
| } |
| |
| /* This is the routine which handles console output (ie. stdout). */ |
| static void console_output(struct virtqueue *vq) |
| { |
| unsigned int head, out, in; |
| struct iovec iov[vq->vring.num]; |
| |
| /* We usually wait in here, for the Guest to give us something. */ |
| head = wait_for_vq_desc(vq, iov, &out, &in); |
| if (in) |
| bad_driver_vq(vq, "Input buffers in console output queue?"); |
| |
| /* writev can return a partial write, so we loop here. */ |
| while (!iov_empty(iov, out)) { |
| int len = writev(STDOUT_FILENO, iov, out); |
| if (len <= 0) { |
| warn("Write to stdout gave %i (%d)", len, errno); |
| break; |
| } |
| iov_consume(vq->dev, iov, out, NULL, len); |
| } |
| |
| /* |
| * We're finished with that buffer: if we're going to sleep, |
| * wait_for_vq_desc() will prod the Guest with an interrupt. |
| */ |
| add_used(vq, head, 0); |
| } |
| |
| /* |
| * The Network |
| * |
| * Handling output for network is also simple: we get all the output buffers |
| * and write them to /dev/net/tun. |
| */ |
| struct net_info { |
| int tunfd; |
| }; |
| |
| static void net_output(struct virtqueue *vq) |
| { |
| struct net_info *net_info = vq->dev->priv; |
| unsigned int head, out, in; |
| struct iovec iov[vq->vring.num]; |
| |
| /* We usually wait in here for the Guest to give us a packet. */ |
| head = wait_for_vq_desc(vq, iov, &out, &in); |
| if (in) |
| bad_driver_vq(vq, "Input buffers in net output queue?"); |
| /* |
| * Send the whole thing through to /dev/net/tun. It expects the exact |
| * same format: what a coincidence! |
| */ |
| if (writev(net_info->tunfd, iov, out) < 0) |
| warnx("Write to tun failed (%d)?", errno); |
| |
| /* |
| * Done with that one; wait_for_vq_desc() will send the interrupt if |
| * all packets are processed. |
| */ |
| add_used(vq, head, 0); |
| } |
| |
| /* |
| * Handling network input is a bit trickier, because I've tried to optimize it. |
| * |
| * First we have a helper routine which tells is if from this file descriptor |
| * (ie. the /dev/net/tun device) will block: |
| */ |
| static bool will_block(int fd) |
| { |
| fd_set fdset; |
| struct timeval zero = { 0, 0 }; |
| FD_ZERO(&fdset); |
| FD_SET(fd, &fdset); |
| return select(fd+1, &fdset, NULL, NULL, &zero) != 1; |
| } |
| |
| /* |
| * This handles packets coming in from the tun device to our Guest. Like all |
| * service routines, it gets called again as soon as it returns, so you don't |
| * see a while(1) loop here. |
| */ |
| static void net_input(struct virtqueue *vq) |
| { |
| int len; |
| unsigned int head, out, in; |
| struct iovec iov[vq->vring.num]; |
| struct net_info *net_info = vq->dev->priv; |
| |
| /* |
| * Get a descriptor to write an incoming packet into. This will also |
| * send an interrupt if they're out of descriptors. |
| */ |
| head = wait_for_vq_desc(vq, iov, &out, &in); |
| if (out) |
| bad_driver_vq(vq, "Output buffers in net input queue?"); |
| |
| /* |
| * If it looks like we'll block reading from the tun device, send them |
| * an interrupt. |
| */ |
| if (vq->pending_used && will_block(net_info->tunfd)) |
| trigger_irq(vq); |
| |
| /* |
| * Read in the packet. This is where we normally wait (when there's no |
| * incoming network traffic). |
| */ |
| len = readv(net_info->tunfd, iov, in); |
| if (len <= 0) |
| warn("Failed to read from tun (%d).", errno); |
| |
| /* |
| * Mark that packet buffer as used, but don't interrupt here. We want |
| * to wait until we've done as much work as we can. |
| */ |
| add_used(vq, head, len); |
| } |
| /*:*/ |
| |
| /* This is the helper to create threads: run the service routine in a loop. */ |
| static int do_thread(void *_vq) |
| { |
| struct virtqueue *vq = _vq; |
| |
| for (;;) |
| vq->service(vq); |
| return 0; |
| } |
| |
| /* |
| * When a child dies, we kill our entire process group with SIGTERM. This |
| * also has the side effect that the shell restores the console for us! |
| */ |
| static void kill_launcher(int signal) |
| { |
| kill(0, SIGTERM); |
| } |
| |
| static void reset_vq_pci_config(struct virtqueue *vq) |
| { |
| vq->pci_config.queue_size = VIRTQUEUE_NUM; |
| vq->pci_config.queue_enable = 0; |
| } |
| |
| static void reset_device(struct device *dev) |
| { |
| struct virtqueue *vq; |
| |
| verbose("Resetting device %s\n", dev->name); |
| |
| /* Clear any features they've acked. */ |
| dev->features_accepted = 0; |
| |
| /* We're going to be explicitly killing threads, so ignore them. */ |
| signal(SIGCHLD, SIG_IGN); |
| |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST present a 0 in queue_enable on reset. |
| * |
| * This means we set it here, and reset the saved ones in every vq. |
| */ |
| dev->mmio->cfg.queue_enable = 0; |
| |
| /* Get rid of the virtqueue threads */ |
| for (vq = dev->vq; vq; vq = vq->next) { |
| vq->last_avail_idx = 0; |
| reset_vq_pci_config(vq); |
| if (vq->thread != (pid_t)-1) { |
| kill(vq->thread, SIGTERM); |
| waitpid(vq->thread, NULL, 0); |
| vq->thread = (pid_t)-1; |
| } |
| } |
| dev->running = false; |
| dev->wrote_features_ok = false; |
| |
| /* Now we care if threads die. */ |
| signal(SIGCHLD, (void *)kill_launcher); |
| } |
| |
| static void cleanup_devices(void) |
| { |
| unsigned int i; |
| |
| for (i = 1; i < MAX_PCI_DEVICES; i++) { |
| struct device *d = devices.pci[i]; |
| if (!d) |
| continue; |
| reset_device(d); |
| } |
| |
| /* If we saved off the original terminal settings, restore them now. */ |
| if (orig_term.c_lflag & (ISIG|ICANON|ECHO)) |
| tcsetattr(STDIN_FILENO, TCSANOW, &orig_term); |
| } |
| |
| /*L:217 |
| * We do PCI. This is mainly done to let us test the kernel virtio PCI |
| * code. |
| */ |
| |
| /* Linux expects a PCI host bridge: ours is a dummy, and first on the bus. */ |
| static struct device pci_host_bridge; |
| |
| static void init_pci_host_bridge(void) |
| { |
| pci_host_bridge.name = "PCI Host Bridge"; |
| pci_host_bridge.config.class = 0x06; /* bridge */ |
| pci_host_bridge.config.subclass = 0; /* host bridge */ |
| devices.pci[0] = &pci_host_bridge; |
| } |
| |
| /* The IO ports used to read the PCI config space. */ |
| #define PCI_CONFIG_ADDR 0xCF8 |
| #define PCI_CONFIG_DATA 0xCFC |
| |
| /* |
| * Not really portable, but does help readability: this is what the Guest |
| * writes to the PCI_CONFIG_ADDR IO port. |
| */ |
| union pci_config_addr { |
| struct { |
| unsigned mbz: 2; |
| unsigned offset: 6; |
| unsigned funcnum: 3; |
| unsigned devnum: 5; |
| unsigned busnum: 8; |
| unsigned reserved: 7; |
| unsigned enabled : 1; |
| } bits; |
| u32 val; |
| }; |
| |
| /* |
| * We cache what they wrote to the address port, so we know what they're |
| * talking about when they access the data port. |
| */ |
| static union pci_config_addr pci_config_addr; |
| |
| static struct device *find_pci_device(unsigned int index) |
| { |
| return devices.pci[index]; |
| } |
| |
| /* PCI can do 1, 2 and 4 byte reads; we handle that here. */ |
| static void ioread(u16 off, u32 v, u32 mask, u32 *val) |
| { |
| assert(off < 4); |
| assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF); |
| *val = (v >> (off * 8)) & mask; |
| } |
| |
| /* PCI can do 1, 2 and 4 byte writes; we handle that here. */ |
| static void iowrite(u16 off, u32 v, u32 mask, u32 *dst) |
| { |
| assert(off < 4); |
| assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF); |
| *dst &= ~(mask << (off * 8)); |
| *dst |= (v & mask) << (off * 8); |
| } |
| |
| /* |
| * Where PCI_CONFIG_DATA accesses depends on the previous write to |
| * PCI_CONFIG_ADDR. |
| */ |
| static struct device *dev_and_reg(u32 *reg) |
| { |
| if (!pci_config_addr.bits.enabled) |
| return NULL; |
| |
| if (pci_config_addr.bits.funcnum != 0) |
| return NULL; |
| |
| if (pci_config_addr.bits.busnum != 0) |
| return NULL; |
| |
| if (pci_config_addr.bits.offset * 4 >= sizeof(struct pci_config)) |
| return NULL; |
| |
| *reg = pci_config_addr.bits.offset; |
| return find_pci_device(pci_config_addr.bits.devnum); |
| } |
| |
| /* |
| * We can get invalid combinations of values while they're writing, so we |
| * only fault if they try to write with some invalid bar/offset/length. |
| */ |
| static bool valid_bar_access(struct device *d, |
| struct virtio_pci_cfg_cap_u32 *cfg_access) |
| { |
| /* We only have 1 bar (BAR0) */ |
| if (cfg_access->cap.bar != 0) |
| return false; |
| |
| /* Check it's within BAR0. */ |
| if (cfg_access->cap.offset >= d->mmio_size |
| || cfg_access->cap.offset + cfg_access->cap.length > d->mmio_size) |
| return false; |
| |
| /* Check length is 1, 2 or 4. */ |
| if (cfg_access->cap.length != 1 |
| && cfg_access->cap.length != 2 |
| && cfg_access->cap.length != 4) |
| return false; |
| |
| /* |
| * 4.1.4.7.2: |
| * |
| * The driver MUST NOT write a cap.offset which is not a multiple of |
| * cap.length (ie. all accesses MUST be aligned). |
| */ |
| if (cfg_access->cap.offset % cfg_access->cap.length != 0) |
| return false; |
| |
| /* Return pointer into word in BAR0. */ |
| return true; |
| } |
| |
| /* Is this accessing the PCI config address port?. */ |
| static bool is_pci_addr_port(u16 port) |
| { |
| return port >= PCI_CONFIG_ADDR && port < PCI_CONFIG_ADDR + 4; |
| } |
| |
| static bool pci_addr_iowrite(u16 port, u32 mask, u32 val) |
| { |
| iowrite(port - PCI_CONFIG_ADDR, val, mask, |
| &pci_config_addr.val); |
| verbose("PCI%s: %#x/%x: bus %u dev %u func %u reg %u\n", |
| pci_config_addr.bits.enabled ? "" : " DISABLED", |
| val, mask, |
| pci_config_addr.bits.busnum, |
| pci_config_addr.bits.devnum, |
| pci_config_addr.bits.funcnum, |
| pci_config_addr.bits.offset); |
| return true; |
| } |
| |
| static void pci_addr_ioread(u16 port, u32 mask, u32 *val) |
| { |
| ioread(port - PCI_CONFIG_ADDR, pci_config_addr.val, mask, val); |
| } |
| |
| /* Is this accessing the PCI config data port?. */ |
| static bool is_pci_data_port(u16 port) |
| { |
| return port >= PCI_CONFIG_DATA && port < PCI_CONFIG_DATA + 4; |
| } |
| |
| static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask); |
| |
| static bool pci_data_iowrite(u16 port, u32 mask, u32 val) |
| { |
| u32 reg, portoff; |
| struct device *d = dev_and_reg(®); |
| |
| /* Complain if they don't belong to a device. */ |
| if (!d) |
| return false; |
| |
| /* They can do 1 byte writes, etc. */ |
| portoff = port - PCI_CONFIG_DATA; |
| |
| /* |
| * PCI uses a weird way to determine the BAR size: the OS |
| * writes all 1's, and sees which ones stick. |
| */ |
| if (&d->config_words[reg] == &d->config.bar[0]) { |
| int i; |
| |
| iowrite(portoff, val, mask, &d->config.bar[0]); |
| for (i = 0; (1 << i) < d->mmio_size; i++) |
| d->config.bar[0] &= ~(1 << i); |
| return true; |
| } else if ((&d->config_words[reg] > &d->config.bar[0] |
| && &d->config_words[reg] <= &d->config.bar[6]) |
| || &d->config_words[reg] == &d->config.expansion_rom_addr) { |
| /* Allow writing to any other BAR, or expansion ROM */ |
| iowrite(portoff, val, mask, &d->config_words[reg]); |
| return true; |
| /* We let them override latency timer and cacheline size */ |
| } else if (&d->config_words[reg] == (void *)&d->config.cacheline_size) { |
| /* Only let them change the first two fields. */ |
| if (mask == 0xFFFFFFFF) |
| mask = 0xFFFF; |
| iowrite(portoff, val, mask, &d->config_words[reg]); |
| return true; |
| } else if (&d->config_words[reg] == (void *)&d->config.command |
| && mask == 0xFFFF) { |
| /* Ignore command writes. */ |
| return true; |
| } else if (&d->config_words[reg] |
| == (void *)&d->config.cfg_access.cap.bar |
| || &d->config_words[reg] |
| == &d->config.cfg_access.cap.length |
| || &d->config_words[reg] |
| == &d->config.cfg_access.cap.offset) { |
| |
| /* |
| * The VIRTIO_PCI_CAP_PCI_CFG capability |
| * provides a backdoor to access the MMIO |
| * regions without mapping them. Weird, but |
| * useful. |
| */ |
| iowrite(portoff, val, mask, &d->config_words[reg]); |
| return true; |
| } else if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) { |
| u32 write_mask; |
| |
| /* |
| * 4.1.4.7.1: |
| * |
| * Upon detecting driver write access to pci_cfg_data, the |
| * device MUST execute a write access at offset cap.offset at |
| * BAR selected by cap.bar using the first cap.length bytes |
| * from pci_cfg_data. |
| */ |
| |
| /* Must be bar 0 */ |
| if (!valid_bar_access(d, &d->config.cfg_access)) |
| return false; |
| |
| iowrite(portoff, val, mask, &d->config.cfg_access.pci_cfg_data); |
| |
| /* |
| * Now emulate a write. The mask we use is set by |
| * len, *not* this write! |
| */ |
| write_mask = (1ULL<<(8*d->config.cfg_access.cap.length)) - 1; |
| verbose("Window writing %#x/%#x to bar %u, offset %u len %u\n", |
| d->config.cfg_access.pci_cfg_data, write_mask, |
| d->config.cfg_access.cap.bar, |
| d->config.cfg_access.cap.offset, |
| d->config.cfg_access.cap.length); |
| |
| emulate_mmio_write(d, d->config.cfg_access.cap.offset, |
| d->config.cfg_access.pci_cfg_data, |
| write_mask); |
| return true; |
| } |
| |
| /* |
| * 4.1.4.1: |
| * |
| * The driver MUST NOT write into any field of the capability |
| * structure, with the exception of those with cap_type |
| * VIRTIO_PCI_CAP_PCI_CFG... |
| */ |
| return false; |
| } |
| |
| static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask); |
| |
| static void pci_data_ioread(u16 port, u32 mask, u32 *val) |
| { |
| u32 reg; |
| struct device *d = dev_and_reg(®); |
| |
| if (!d) |
| return; |
| |
| /* Read through the PCI MMIO access window is special */ |
| if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) { |
| u32 read_mask; |
| |
| /* |
| * 4.1.4.7.1: |
| * |
| * Upon detecting driver read access to pci_cfg_data, the |
| * device MUST execute a read access of length cap.length at |
| * offset cap.offset at BAR selected by cap.bar and store the |
| * first cap.length bytes in pci_cfg_data. |
| */ |
| /* Must be bar 0 */ |
| if (!valid_bar_access(d, &d->config.cfg_access)) |
| bad_driver(d, |
| "Invalid cfg_access to bar%u, offset %u len %u", |
| d->config.cfg_access.cap.bar, |
| d->config.cfg_access.cap.offset, |
| d->config.cfg_access.cap.length); |
| |
| /* |
| * Read into the window. The mask we use is set by |
| * len, *not* this read! |
| */ |
| read_mask = (1ULL<<(8*d->config.cfg_access.cap.length))-1; |
| d->config.cfg_access.pci_cfg_data |
| = emulate_mmio_read(d, |
| d->config.cfg_access.cap.offset, |
| read_mask); |
| verbose("Window read %#x/%#x from bar %u, offset %u len %u\n", |
| d->config.cfg_access.pci_cfg_data, read_mask, |
| d->config.cfg_access.cap.bar, |
| d->config.cfg_access.cap.offset, |
| d->config.cfg_access.cap.length); |
| } |
| ioread(port - PCI_CONFIG_DATA, d->config_words[reg], mask, val); |
| } |
| |
| /*L:216 |
| * This is where we emulate a handful of Guest instructions. It's ugly |
| * and we used to do it in the kernel but it grew over time. |
| */ |
| |
| /* |
| * We use the ptrace syscall's pt_regs struct to talk about registers |
| * to lguest: these macros convert the names to the offsets. |
| */ |
| #define getreg(name) getreg_off(offsetof(struct user_regs_struct, name)) |
| #define setreg(name, val) \ |
| setreg_off(offsetof(struct user_regs_struct, name), (val)) |
| |
| static u32 getreg_off(size_t offset) |
| { |
| u32 r; |
| unsigned long args[] = { LHREQ_GETREG, offset }; |
| |
| if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0) |
| err(1, "Getting register %u", offset); |
| if (pread(lguest_fd, &r, sizeof(r), cpu_id) != sizeof(r)) |
| err(1, "Reading register %u", offset); |
| |
| return r; |
| } |
| |
| static void setreg_off(size_t offset, u32 val) |
| { |
| unsigned long args[] = { LHREQ_SETREG, offset, val }; |
| |
| if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0) |
| err(1, "Setting register %u", offset); |
| } |
| |
| /* Get register by instruction encoding */ |
| static u32 getreg_num(unsigned regnum, u32 mask) |
| { |
| /* 8 bit ops use regnums 4-7 for high parts of word */ |
| if (mask == 0xFF && (regnum & 0x4)) |
| return getreg_num(regnum & 0x3, 0xFFFF) >> 8; |
| |
| switch (regnum) { |
| case 0: return getreg(eax) & mask; |
| case 1: return getreg(ecx) & mask; |
| case 2: return getreg(edx) & mask; |
| case 3: return getreg(ebx) & mask; |
| case 4: return getreg(esp) & mask; |
| case 5: return getreg(ebp) & mask; |
| case 6: return getreg(esi) & mask; |
| case 7: return getreg(edi) & mask; |
| } |
| abort(); |
| } |
| |
| /* Set register by instruction encoding */ |
| static void setreg_num(unsigned regnum, u32 val, u32 mask) |
| { |
| /* Don't try to set bits out of range */ |
| assert(~(val & ~mask)); |
| |
| /* 8 bit ops use regnums 4-7 for high parts of word */ |
| if (mask == 0xFF && (regnum & 0x4)) { |
| /* Construct the 16 bits we want. */ |
| val = (val << 8) | getreg_num(regnum & 0x3, 0xFF); |
| setreg_num(regnum & 0x3, val, 0xFFFF); |
| return; |
| } |
| |
| switch (regnum) { |
| case 0: setreg(eax, val | (getreg(eax) & ~mask)); return; |
| case 1: setreg(ecx, val | (getreg(ecx) & ~mask)); return; |
| case 2: setreg(edx, val | (getreg(edx) & ~mask)); return; |
| case 3: setreg(ebx, val | (getreg(ebx) & ~mask)); return; |
| case 4: setreg(esp, val | (getreg(esp) & ~mask)); return; |
| case 5: setreg(ebp, val | (getreg(ebp) & ~mask)); return; |
| case 6: setreg(esi, val | (getreg(esi) & ~mask)); return; |
| case 7: setreg(edi, val | (getreg(edi) & ~mask)); return; |
| } |
| abort(); |
| } |
| |
| /* Get bytes of displacement appended to instruction, from r/m encoding */ |
| static u32 insn_displacement_len(u8 mod_reg_rm) |
| { |
| /* Switch on the mod bits */ |
| switch (mod_reg_rm >> 6) { |
| case 0: |
| /* If mod == 0, and r/m == 101, 16-bit displacement follows */ |
| if ((mod_reg_rm & 0x7) == 0x5) |
| return 2; |
| /* Normally, mod == 0 means no literal displacement */ |
| return 0; |
| case 1: |
| /* One byte displacement */ |
| return 1; |
| case 2: |
| /* Four byte displacement */ |
| return 4; |
| case 3: |
| /* Register mode */ |
| return 0; |
| } |
| abort(); |
| } |
| |
| static void emulate_insn(const u8 insn[]) |
| { |
| unsigned long args[] = { LHREQ_TRAP, 13 }; |
| unsigned int insnlen = 0, in = 0, small_operand = 0, byte_access; |
| unsigned int eax, port, mask; |
| /* |
| * Default is to return all-ones on IO port reads, which traditionally |
| * means "there's nothing there". |
| */ |
| u32 val = 0xFFFFFFFF; |
| |
| /* |
| * This must be the Guest kernel trying to do something, not userspace! |
| * The bottom two bits of the CS segment register are the privilege |
| * level. |
| */ |
| if ((getreg(xcs) & 3) != 0x1) |
| goto no_emulate; |
| |
| /* Decoding x86 instructions is icky. */ |
| |
| /* |
| * Around 2.6.33, the kernel started using an emulation for the |
| * cmpxchg8b instruction in early boot on many configurations. This |
| * code isn't paravirtualized, and it tries to disable interrupts. |
| * Ignore it, which will Mostly Work. |
| */ |
| if (insn[insnlen] == 0xfa) { |
| /* "cli", or Clear Interrupt Enable instruction. Skip it. */ |
| insnlen = 1; |
| goto skip_insn; |
| } |
| |
| /* |
| * 0x66 is an "operand prefix". It means a 16, not 32 bit in/out. |
| */ |
| if (insn[insnlen] == 0x66) { |
| small_operand = 1; |
| /* The instruction is 1 byte so far, read the next byte. */ |
| insnlen = 1; |
| } |
| |
| /* If the lower bit isn't set, it's a single byte access */ |
| byte_access = !(insn[insnlen] & 1); |
| |
| /* |
| * Now we can ignore the lower bit and decode the 4 opcodes |
| * we need to emulate. |
| */ |
| switch (insn[insnlen] & 0xFE) { |
| case 0xE4: /* in <next byte>,%al */ |
| port = insn[insnlen+1]; |
| insnlen += 2; |
| in = 1; |
| break; |
| case 0xEC: /* in (%dx),%al */ |
| port = getreg(edx) & 0xFFFF; |
| insnlen += 1; |
| in = 1; |
| break; |
| case 0xE6: /* out %al,<next byte> */ |
| port = insn[insnlen+1]; |
| insnlen += 2; |
| break; |
| case 0xEE: /* out %al,(%dx) */ |
| port = getreg(edx) & 0xFFFF; |
| insnlen += 1; |
| break; |
| default: |
| /* OK, we don't know what this is, can't emulate. */ |
| goto no_emulate; |
| } |
| |
| /* Set a mask of the 1, 2 or 4 bytes, depending on size of IO */ |
| if (byte_access) |
| mask = 0xFF; |
| else if (small_operand) |
| mask = 0xFFFF; |
| else |
| mask = 0xFFFFFFFF; |
| |
| /* |
| * If it was an "IN" instruction, they expect the result to be read |
| * into %eax, so we change %eax. |
| */ |
| eax = getreg(eax); |
| |
| if (in) { |
| /* This is the PS/2 keyboard status; 1 means ready for output */ |
| if (port == 0x64) |
| val = 1; |
| else if (is_pci_addr_port(port)) |
| pci_addr_ioread(port, mask, &val); |
| else if (is_pci_data_port(port)) |
| pci_data_ioread(port, mask, &val); |
| |
| /* Clear the bits we're about to read */ |
| eax &= ~mask; |
| /* Copy bits in from val. */ |
| eax |= val & mask; |
| /* Now update the register. */ |
| setreg(eax, eax); |
| } else { |
| if (is_pci_addr_port(port)) { |
| if (!pci_addr_iowrite(port, mask, eax)) |
| goto bad_io; |
| } else if (is_pci_data_port(port)) { |
| if (!pci_data_iowrite(port, mask, eax)) |
| goto bad_io; |
| } |
| /* There are many other ports, eg. CMOS clock, serial |
| * and parallel ports, so we ignore them all. */ |
| } |
| |
| verbose("IO %s of %x to %u: %#08x\n", |
| in ? "IN" : "OUT", mask, port, eax); |
| skip_insn: |
| /* Finally, we've "done" the instruction, so move past it. */ |
| setreg(eip, getreg(eip) + insnlen); |
| return; |
| |
| bad_io: |
| warnx("Attempt to %s port %u (%#x mask)", |
| in ? "read from" : "write to", port, mask); |
| |
| no_emulate: |
| /* Inject trap into Guest. */ |
| if (write(lguest_fd, args, sizeof(args)) < 0) |
| err(1, "Reinjecting trap 13 for fault at %#x", getreg(eip)); |
| } |
| |
| static struct device *find_mmio_region(unsigned long paddr, u32 *off) |
| { |
| unsigned int i; |
| |
| for (i = 1; i < MAX_PCI_DEVICES; i++) { |
| struct device *d = devices.pci[i]; |
| |
| if (!d) |
| continue; |
| if (paddr < d->mmio_addr) |
| continue; |
| if (paddr >= d->mmio_addr + d->mmio_size) |
| continue; |
| *off = paddr - d->mmio_addr; |
| return d; |
| } |
| return NULL; |
| } |
| |
| /* FIXME: Use vq array. */ |
| static struct virtqueue *vq_by_num(struct device *d, u32 num) |
| { |
| struct virtqueue *vq = d->vq; |
| |
| while (num-- && vq) |
| vq = vq->next; |
| |
| return vq; |
| } |
| |
| static void save_vq_config(const struct virtio_pci_common_cfg *cfg, |
| struct virtqueue *vq) |
| { |
| vq->pci_config = *cfg; |
| } |
| |
| static void restore_vq_config(struct virtio_pci_common_cfg *cfg, |
| struct virtqueue *vq) |
| { |
| /* Only restore the per-vq part */ |
| size_t off = offsetof(struct virtio_pci_common_cfg, queue_size); |
| |
| memcpy((void *)cfg + off, (void *)&vq->pci_config + off, |
| sizeof(*cfg) - off); |
| } |
| |
| /* |
| * 4.1.4.3.2: |
| * |
| * The driver MUST configure the other virtqueue fields before |
| * enabling the virtqueue with queue_enable. |
| * |
| * When they enable the virtqueue, we check that their setup is valid. |
| */ |
| static void check_virtqueue(struct device *d, struct virtqueue *vq) |
| { |
| /* Because lguest is 32 bit, all the descriptor high bits must be 0 */ |
| if (vq->pci_config.queue_desc_hi |
| || vq->pci_config.queue_avail_hi |
| || vq->pci_config.queue_used_hi) |
| bad_driver_vq(vq, "invalid 64-bit queue address"); |
| |
| /* |
| * 2.4.1: |
| * |
| * The driver MUST ensure that the physical address of the first byte |
| * of each virtqueue part is a multiple of the specified alignment |
| * value in the above table. |
| */ |
| if (vq->pci_config.queue_desc_lo % 16 |
| || vq->pci_config.queue_avail_lo % 2 |
| || vq->pci_config.queue_used_lo % 4) |
| bad_driver_vq(vq, "invalid alignment in queue addresses"); |
| |
| /* Initialize the virtqueue and check they're all in range. */ |
| vq->vring.num = vq->pci_config.queue_size; |
| vq->vring.desc = check_pointer(vq->dev, |
| vq->pci_config.queue_desc_lo, |
| sizeof(*vq->vring.desc) * vq->vring.num); |
| vq->vring.avail = check_pointer(vq->dev, |
| vq->pci_config.queue_avail_lo, |
| sizeof(*vq->vring.avail) |
| + (sizeof(vq->vring.avail->ring[0]) |
| * vq->vring.num)); |
| vq->vring.used = check_pointer(vq->dev, |
| vq->pci_config.queue_used_lo, |
| sizeof(*vq->vring.used) |
| + (sizeof(vq->vring.used->ring[0]) |
| * vq->vring.num)); |
| |
| /* |
| * 2.4.9.1: |
| * |
| * The driver MUST initialize flags in the used ring to 0 |
| * when allocating the used ring. |
| */ |
| if (vq->vring.used->flags != 0) |
| bad_driver_vq(vq, "invalid initial used.flags %#x", |
| vq->vring.used->flags); |
| } |
| |
| static void start_virtqueue(struct virtqueue *vq) |
| { |
| /* |
| * Create stack for thread. Since the stack grows upwards, we point |
| * the stack pointer to the end of this region. |
| */ |
| char *stack = malloc(32768); |
| |
| /* Create a zero-initialized eventfd. */ |
| vq->eventfd = eventfd(0, 0); |
| if (vq->eventfd < 0) |
| err(1, "Creating eventfd"); |
| |
| /* |
| * CLONE_VM: because it has to access the Guest memory, and SIGCHLD so |
| * we get a signal if it dies. |
| */ |
| vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq); |
| if (vq->thread == (pid_t)-1) |
| err(1, "Creating clone"); |
| } |
| |
| static void start_virtqueues(struct device *d) |
| { |
| struct virtqueue *vq; |
| |
| for (vq = d->vq; vq; vq = vq->next) { |
| if (vq->pci_config.queue_enable) |
| start_virtqueue(vq); |
| } |
| } |
| |
| static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask) |
| { |
| struct virtqueue *vq; |
| |
| switch (off) { |
| case offsetof(struct virtio_pci_mmio, cfg.device_feature_select): |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST present the feature bits it is offering in |
| * device_feature, starting at bit device_feature_select ∗ 32 |
| * for any device_feature_select written by the driver |
| */ |
| if (val == 0) |
| d->mmio->cfg.device_feature = d->features; |
| else if (val == 1) |
| d->mmio->cfg.device_feature = (d->features >> 32); |
| else |
| d->mmio->cfg.device_feature = 0; |
| goto feature_write_through32; |
| case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select): |
| if (val > 1) |
| bad_driver(d, "Unexpected driver select %u", val); |
| goto feature_write_through32; |
| case offsetof(struct virtio_pci_mmio, cfg.guest_feature): |
| if (d->mmio->cfg.guest_feature_select == 0) { |
| d->features_accepted &= ~((u64)0xFFFFFFFF); |
| d->features_accepted |= val; |
| } else { |
| assert(d->mmio->cfg.guest_feature_select == 1); |
| d->features_accepted &= 0xFFFFFFFF; |
| d->features_accepted |= ((u64)val) << 32; |
| } |
| /* |
| * 2.2.1: |
| * |
| * The driver MUST NOT accept a feature which the device did |
| * not offer |
| */ |
| if (d->features_accepted & ~d->features) |
| bad_driver(d, "over-accepted features %#llx of %#llx", |
| d->features_accepted, d->features); |
| goto feature_write_through32; |
| case offsetof(struct virtio_pci_mmio, cfg.device_status): { |
| u8 prev; |
| |
| verbose("%s: device status -> %#x\n", d->name, val); |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST reset when 0 is written to device_status, |
| * and present a 0 in device_status once that is done. |
| */ |
| if (val == 0) { |
| reset_device(d); |
| goto write_through8; |
| } |
| |
| /* 2.1.1: The driver MUST NOT clear a device status bit. */ |
| if (d->mmio->cfg.device_status & ~val) |
| bad_driver(d, "unset of device status bit %#x -> %#x", |
| d->mmio->cfg.device_status, val); |
| |
| /* |
| * 2.1.2: |
| * |
| * The device MUST NOT consume buffers or notify the driver |
| * before DRIVER_OK. |
| */ |
| if (val & VIRTIO_CONFIG_S_DRIVER_OK |
| && !(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK)) |
| start_virtqueues(d); |
| |
| /* |
| * 3.1.1: |
| * |
| * The driver MUST follow this sequence to initialize a device: |
| * - Reset the device. |
| * - Set the ACKNOWLEDGE status bit: the guest OS has |
| * notice the device. |
| * - Set the DRIVER status bit: the guest OS knows how |
| * to drive the device. |
| * - Read device feature bits, and write the subset |
| * of feature bits understood by the OS and driver |
| * to the device. During this step the driver MAY |
| * read (but MUST NOT write) the device-specific |
| * configuration fields to check that it can |
| * support the device before accepting it. |
| * - Set the FEATURES_OK status bit. The driver |
| * MUST not accept new feature bits after this |
| * step. |
| * - Re-read device status to ensure the FEATURES_OK |
| * bit is still set: otherwise, the device does |
| * not support our subset of features and the |
| * device is unusable. |
| * - Perform device-specific setup, including |
| * discovery of virtqueues for the device, |
| * optional per-bus setup, reading and possibly |
| * writing the device’s virtio configuration |
| * space, and population of virtqueues. |
| * - Set the DRIVER_OK status bit. At this point the |
| * device is “live”. |
| */ |
| prev = 0; |
| switch (val & ~d->mmio->cfg.device_status) { |
| case VIRTIO_CONFIG_S_DRIVER_OK: |
| prev |= VIRTIO_CONFIG_S_FEATURES_OK; /* fall thru */ |
| case VIRTIO_CONFIG_S_FEATURES_OK: |
| prev |= VIRTIO_CONFIG_S_DRIVER; /* fall thru */ |
| case VIRTIO_CONFIG_S_DRIVER: |
| prev |= VIRTIO_CONFIG_S_ACKNOWLEDGE; /* fall thru */ |
| case VIRTIO_CONFIG_S_ACKNOWLEDGE: |
| break; |
| default: |
| bad_driver(d, "unknown device status bit %#x -> %#x", |
| d->mmio->cfg.device_status, val); |
| } |
| if (d->mmio->cfg.device_status != prev) |
| bad_driver(d, "unexpected status transition %#x -> %#x", |
| d->mmio->cfg.device_status, val); |
| |
| /* If they just wrote FEATURES_OK, we make sure they read */ |
| switch (val & ~d->mmio->cfg.device_status) { |
| case VIRTIO_CONFIG_S_FEATURES_OK: |
| d->wrote_features_ok = true; |
| break; |
| case VIRTIO_CONFIG_S_DRIVER_OK: |
| if (d->wrote_features_ok) |
| bad_driver(d, "did not re-read FEATURES_OK"); |
| break; |
| } |
| goto write_through8; |
| } |
| case offsetof(struct virtio_pci_mmio, cfg.queue_select): |
| vq = vq_by_num(d, val); |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST present a 0 in queue_size if the virtqueue |
| * corresponding to the current queue_select is unavailable. |
| */ |
| if (!vq) { |
| d->mmio->cfg.queue_size = 0; |
| goto write_through16; |
| } |
| /* Save registers for old vq, if it was a valid vq */ |
| if (d->mmio->cfg.queue_size) |
| save_vq_config(&d->mmio->cfg, |
| vq_by_num(d, d->mmio->cfg.queue_select)); |
| /* Restore the registers for the queue they asked for */ |
| restore_vq_config(&d->mmio->cfg, vq); |
| goto write_through16; |
| case offsetof(struct virtio_pci_mmio, cfg.queue_size): |
| /* |
| * 4.1.4.3.2: |
| * |
| * The driver MUST NOT write a value which is not a power of 2 |
| * to queue_size. |
| */ |
| if (val & (val-1)) |
| bad_driver(d, "invalid queue size %u", val); |
| if (d->mmio->cfg.queue_enable) |
| bad_driver(d, "changing queue size on live device"); |
| goto write_through16; |
| case offsetof(struct virtio_pci_mmio, cfg.queue_msix_vector): |
| bad_driver(d, "attempt to set MSIX vector to %u", val); |
| case offsetof(struct virtio_pci_mmio, cfg.queue_enable): { |
| struct virtqueue *vq = vq_by_num(d, d->mmio->cfg.queue_select); |
| |
| /* |
| * 4.1.4.3.2: |
| * |
| * The driver MUST NOT write a 0 to queue_enable. |
| */ |
| if (val != 1) |
| bad_driver(d, "setting queue_enable to %u", val); |
| |
| /* |
| * 3.1.1: |
| * |
| * 7. Perform device-specific setup, including discovery of |
| * virtqueues for the device, optional per-bus setup, |
| * reading and possibly writing the device’s virtio |
| * configuration space, and population of virtqueues. |
| * 8. Set the DRIVER_OK status bit. |
| * |
| * All our devices require all virtqueues to be enabled, so |
| * they should have done that before setting DRIVER_OK. |
| */ |
| if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK) |
| bad_driver(d, "enabling vq after DRIVER_OK"); |
| |
| d->mmio->cfg.queue_enable = val; |
| save_vq_config(&d->mmio->cfg, vq); |
| check_virtqueue(d, vq); |
| goto write_through16; |
| } |
| case offsetof(struct virtio_pci_mmio, cfg.queue_notify_off): |
| bad_driver(d, "attempt to write to queue_notify_off"); |
| case offsetof(struct virtio_pci_mmio, cfg.queue_desc_lo): |
| case offsetof(struct virtio_pci_mmio, cfg.queue_desc_hi): |
| case offsetof(struct virtio_pci_mmio, cfg.queue_avail_lo): |
| case offsetof(struct virtio_pci_mmio, cfg.queue_avail_hi): |
| case offsetof(struct virtio_pci_mmio, cfg.queue_used_lo): |
| case offsetof(struct virtio_pci_mmio, cfg.queue_used_hi): |
| /* |
| * 4.1.4.3.2: |
| * |
| * The driver MUST configure the other virtqueue fields before |
| * enabling the virtqueue with queue_enable. |
| */ |
| if (d->mmio->cfg.queue_enable) |
| bad_driver(d, "changing queue on live device"); |
| |
| /* |
| * 3.1.1: |
| * |
| * The driver MUST follow this sequence to initialize a device: |
| *... |
| * 5. Set the FEATURES_OK status bit. The driver MUST not |
| * accept new feature bits after this step. |
| */ |
| if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK)) |
| bad_driver(d, "setting up vq before FEATURES_OK"); |
| |
| /* |
| * 6. Re-read device status to ensure the FEATURES_OK bit is |
| * still set... |
| */ |
| if (d->wrote_features_ok) |
| bad_driver(d, "didn't re-read FEATURES_OK before setup"); |
| |
| goto write_through32; |
| case offsetof(struct virtio_pci_mmio, notify): |
| vq = vq_by_num(d, val); |
| if (!vq) |
| bad_driver(d, "Invalid vq notification on %u", val); |
| /* Notify the process handling this vq by adding 1 to eventfd */ |
| write(vq->eventfd, "\1\0\0\0\0\0\0\0", 8); |
| goto write_through16; |
| case offsetof(struct virtio_pci_mmio, isr): |
| bad_driver(d, "Unexpected write to isr"); |
| /* Weird corner case: write to emerg_wr of console */ |
| case sizeof(struct virtio_pci_mmio) |
| + offsetof(struct virtio_console_config, emerg_wr): |
| if (strcmp(d->name, "console") == 0) { |
| char c = val; |
| write(STDOUT_FILENO, &c, 1); |
| goto write_through32; |
| } |
| /* Fall through... */ |
| default: |
| /* |
| * 4.1.4.3.2: |
| * |
| * The driver MUST NOT write to device_feature, num_queues, |
| * config_generation or queue_notify_off. |
| */ |
| bad_driver(d, "Unexpected write to offset %u", off); |
| } |
| |
| feature_write_through32: |
| /* |
| * 3.1.1: |
| * |
| * The driver MUST follow this sequence to initialize a device: |
| *... |
| * - Set the DRIVER status bit: the guest OS knows how |
| * to drive the device. |
| * - Read device feature bits, and write the subset |
| * of feature bits understood by the OS and driver |
| * to the device. |
| *... |
| * - Set the FEATURES_OK status bit. The driver MUST not |
| * accept new feature bits after this step. |
| */ |
| if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER)) |
| bad_driver(d, "feature write before VIRTIO_CONFIG_S_DRIVER"); |
| if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK) |
| bad_driver(d, "feature write after VIRTIO_CONFIG_S_FEATURES_OK"); |
| |
| /* |
| * 4.1.3.1: |
| * |
| * The driver MUST access each field using the “natural” access |
| * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for |
| * 16-bit fields and 8-bit accesses for 8-bit fields. |
| */ |
| write_through32: |
| if (mask != 0xFFFFFFFF) { |
| bad_driver(d, "non-32-bit write to offset %u (%#x)", |
| off, getreg(eip)); |
| return; |
| } |
| memcpy((char *)d->mmio + off, &val, 4); |
| return; |
| |
| write_through16: |
| if (mask != 0xFFFF) |
| bad_driver(d, "non-16-bit write to offset %u (%#x)", |
| off, getreg(eip)); |
| memcpy((char *)d->mmio + off, &val, 2); |
| return; |
| |
| write_through8: |
| if (mask != 0xFF) |
| bad_driver(d, "non-8-bit write to offset %u (%#x)", |
| off, getreg(eip)); |
| memcpy((char *)d->mmio + off, &val, 1); |
| return; |
| } |
| |
| static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask) |
| { |
| u8 isr; |
| u32 val = 0; |
| |
| switch (off) { |
| case offsetof(struct virtio_pci_mmio, cfg.device_feature_select): |
| case offsetof(struct virtio_pci_mmio, cfg.device_feature): |
| case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select): |
| case offsetof(struct virtio_pci_mmio, cfg.guest_feature): |
| /* |
| * 3.1.1: |
| * |
| * The driver MUST follow this sequence to initialize a device: |
| *... |
| * - Set the DRIVER status bit: the guest OS knows how |
| * to drive the device. |
| * - Read device feature bits, and write the subset |
| * of feature bits understood by the OS and driver |
| * to the device. |
| */ |
| if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER)) |
| bad_driver(d, |
| "feature read before VIRTIO_CONFIG_S_DRIVER"); |
| goto read_through32; |
| case offsetof(struct virtio_pci_mmio, cfg.msix_config): |
| bad_driver(d, "read of msix_config"); |
| case offsetof(struct virtio_pci_mmio, cfg.num_queues): |
| goto read_through16; |
| case offsetof(struct virtio_pci_mmio, cfg.device_status): |
| /* As they did read, any write of FEATURES_OK is now fine. */ |
| d->wrote_features_ok = false; |
| goto read_through8; |
| case offsetof(struct virtio_pci_mmio, cfg.config_generation): |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST present a changed config_generation after |
| * the driver has read a device-specific configuration value |
| * which has changed since any part of the device-specific |
| * configuration was last read. |
| * |
| * This is simple: none of our devices change config, so this |
| * is always 0. |
| */ |
| goto read_through8; |
| case offsetof(struct virtio_pci_mmio, notify): |
| /* |
| * 3.1.1: |
| * |
| * The driver MUST NOT notify the device before setting |
| * DRIVER_OK. |
| */ |
| if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK)) |
| bad_driver(d, "notify before VIRTIO_CONFIG_S_DRIVER_OK"); |
| goto read_through16; |
| case offsetof(struct virtio_pci_mmio, isr): |
| if (mask != 0xFF) |
| bad_driver(d, "non-8-bit read from offset %u (%#x)", |
| off, getreg(eip)); |
| isr = d->mmio->isr; |
| /* |
| * 4.1.4.5.1: |
| * |
| * The device MUST reset ISR status to 0 on driver read. |
| */ |
| d->mmio->isr = 0; |
| return isr; |
| case offsetof(struct virtio_pci_mmio, padding): |
| bad_driver(d, "read from padding (%#x)", getreg(eip)); |
| default: |
| /* Read from device config space, beware unaligned overflow */ |
| if (off > d->mmio_size - 4) |
| bad_driver(d, "read past end (%#x)", getreg(eip)); |
| |
| /* |
| * 3.1.1: |
| * The driver MUST follow this sequence to initialize a device: |
| *... |
| * 3. Set the DRIVER status bit: the guest OS knows how to |
| * drive the device. |
| * 4. Read device feature bits, and write the subset of |
| * feature bits understood by the OS and driver to the |
| * device. During this step the driver MAY read (but MUST NOT |
| * write) the device-specific configuration fields to check |
| * that it can support the device before accepting it. |
| */ |
| if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER)) |
| bad_driver(d, |
| "config read before VIRTIO_CONFIG_S_DRIVER"); |
| |
| if (mask == 0xFFFFFFFF) |
| goto read_through32; |
| else if (mask == 0xFFFF) |
| goto read_through16; |
| else |
| goto read_through8; |
| } |
| |
| /* |
| * 4.1.3.1: |
| * |
| * The driver MUST access each field using the “natural” access |
| * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for |
| * 16-bit fields and 8-bit accesses for 8-bit fields. |
| */ |
| read_through32: |
| if (mask != 0xFFFFFFFF) |
| bad_driver(d, "non-32-bit read to offset %u (%#x)", |
| off, getreg(eip)); |
| memcpy(&val, (char *)d->mmio + off, 4); |
| return val; |
| |
| read_through16: |
| if (mask != 0xFFFF) |
| bad_driver(d, "non-16-bit read to offset %u (%#x)", |
| off, getreg(eip)); |
| memcpy(&val, (char *)d->mmio + off, 2); |
| return val; |
| |
| read_through8: |
| if (mask != 0xFF) |
| bad_driver(d, "non-8-bit read to offset %u (%#x)", |
| off, getreg(eip)); |
| memcpy(&val, (char *)d->mmio + off, 1); |
| return val; |
| } |
| |
| static void emulate_mmio(unsigned long paddr, const u8 *insn) |
| { |
| u32 val, off, mask = 0xFFFFFFFF, insnlen = 0; |
| struct device *d = find_mmio_region(paddr, &off); |
| unsigned long args[] = { LHREQ_TRAP, 14 }; |
| |
| if (!d) { |
| warnx("MMIO touching %#08lx (not a device)", paddr); |
| goto reinject; |
| } |
| |
| /* Prefix makes it a 16 bit op */ |
| if (insn[0] == 0x66) { |
| mask = 0xFFFF; |
| insnlen++; |
| } |
| |
| /* iowrite */ |
| if (insn[insnlen] == 0x89) { |
| /* Next byte is r/m byte: bits 3-5 are register. */ |
| val = getreg_num((insn[insnlen+1] >> 3) & 0x7, mask); |
| emulate_mmio_write(d, off, val, mask); |
| insnlen += 2 + insn_displacement_len(insn[insnlen+1]); |
| } else if (insn[insnlen] == 0x8b) { /* ioread */ |
| /* Next byte is r/m byte: bits 3-5 are register. */ |
| val = emulate_mmio_read(d, off, mask); |
| setreg_num((insn[insnlen+1] >> 3) & 0x7, val, mask); |
| insnlen += 2 + insn_displacement_len(insn[insnlen+1]); |
| } else if (insn[0] == 0x88) { /* 8-bit iowrite */ |
| mask = 0xff; |
| /* Next byte is r/m byte: bits 3-5 are register. */ |
| val = getreg_num((insn[1] >> 3) & 0x7, mask); |
| emulate_mmio_write(d, off, val, mask); |
| insnlen = 2 + insn_displacement_len(insn[1]); |
| } else if (insn[0] == 0x8a) { /* 8-bit ioread */ |
| mask = 0xff; |
| val = emulate_mmio_read(d, off, mask); |
| setreg_num((insn[1] >> 3) & 0x7, val, mask); |
| insnlen = 2 + insn_displacement_len(insn[1]); |
| } else { |
| warnx("Unknown MMIO instruction touching %#08lx:" |
| " %02x %02x %02x %02x at %u", |
| paddr, insn[0], insn[1], insn[2], insn[3], getreg(eip)); |
| reinject: |
| /* Inject trap into Guest. */ |
| if (write(lguest_fd, args, sizeof(args)) < 0) |
| err(1, "Reinjecting trap 14 for fault at %#x", |
| getreg(eip)); |
| return; |
| } |
| |
| /* Finally, we've "done" the instruction, so move past it. */ |
| setreg(eip, getreg(eip) + insnlen); |
| } |
| |
| /*L:190 |
| * Device Setup |
| * |
| * All devices need a descriptor so the Guest knows it exists, and a "struct |
| * device" so the Launcher can keep track of it. We have common helper |
| * routines to allocate and manage them. |
| */ |
| static void add_pci_virtqueue(struct device *dev, |
| void (*service)(struct virtqueue *), |
| const char *name) |
| { |
| struct virtqueue **i, *vq = malloc(sizeof(*vq)); |
| |
| /* Initialize the virtqueue */ |
| vq->next = NULL; |
| vq->last_avail_idx = 0; |
| vq->dev = dev; |
| vq->name = name; |
| |
| /* |
| * This is the routine the service thread will run, and its Process ID |
| * once it's running. |
| */ |
| vq->service = service; |
| vq->thread = (pid_t)-1; |
| |
| /* Initialize the configuration. */ |
| reset_vq_pci_config(vq); |
| vq->pci_config.queue_notify_off = 0; |
| |
| /* Add one to the number of queues */ |
| vq->dev->mmio->cfg.num_queues++; |
| |
| /* |
| * Add to tail of list, so dev->vq is first vq, dev->vq->next is |
| * second. |
| */ |
| for (i = &dev->vq; *i; i = &(*i)->next); |
| *i = vq; |
| } |
| |
| /* The Guest accesses the feature bits via the PCI common config MMIO region */ |
| static void add_pci_feature(struct device *dev, unsigned bit) |
| { |
| dev->features |= (1ULL << bit); |
| } |
| |
| /* For devices with no config. */ |
| static void no_device_config(struct device *dev) |
| { |
| dev->mmio_addr = get_mmio_region(dev->mmio_size); |
| |
| dev->config.bar[0] = dev->mmio_addr; |
| /* Bottom 4 bits must be zero */ |
| assert(~(dev->config.bar[0] & 0xF)); |
| } |
| |
| /* This puts the device config into BAR0 */ |
| static void set_device_config(struct device *dev, const void *conf, size_t len) |
| { |
| /* Set up BAR 0 */ |
| dev->mmio_size += len; |
| dev->mmio = realloc(dev->mmio, dev->mmio_size); |
| memcpy(dev->mmio + 1, conf, len); |
| |
| /* |
| * 4.1.4.6: |
| * |
| * The device MUST present at least one VIRTIO_PCI_CAP_DEVICE_CFG |
| * capability for any device type which has a device-specific |
| * configuration. |
| */ |
| /* Hook up device cfg */ |
| dev->config.cfg_access.cap.cap_next |
| = offsetof(struct pci_config, device); |
| |
| /* |
| * 4.1.4.6.1: |
| * |
| * The offset for the device-specific configuration MUST be 4-byte |
| * aligned. |
| */ |
| assert(dev->config.cfg_access.cap.cap_next % 4 == 0); |
| |
| /* Fix up device cfg field length. */ |
| dev->config.device.length = len; |
| |
| /* The rest is the same as the no-config case */ |
| no_device_config(dev); |
| } |
| |
| static void init_cap(struct virtio_pci_cap *cap, size_t caplen, int type, |
| size_t bar_offset, size_t bar_bytes, u8 next) |
| { |
| cap->cap_vndr = PCI_CAP_ID_VNDR; |
| cap->cap_next = next; |
| cap->cap_len = caplen; |
| cap->cfg_type = type; |
| cap->bar = 0; |
| memset(cap->padding, 0, sizeof(cap->padding)); |
| cap->offset = bar_offset; |
| cap->length = bar_bytes; |
| } |
| |
| /* |
| * This sets up the pci_config structure, as defined in the virtio 1.0 |
| * standard (and PCI standard). |
| */ |
| static void init_pci_config(struct pci_config *pci, u16 type, |
| u8 class, u8 subclass) |
| { |
| size_t bar_offset, bar_len; |
| |
| /* |
| * 4.1.4.4.1: |
| * |
| * The device MUST either present notify_off_multiplier as an even |
| * power of 2, or present notify_off_multiplier as 0. |
| * |
| * 2.1.2: |
| * |
| * The device MUST initialize device status to 0 upon reset. |
| */ |
| memset(pci, 0, sizeof(*pci)); |
| |
| /* 4.1.2.1: Devices MUST have the PCI Vendor ID 0x1AF4 */ |
| pci->vendor_id = 0x1AF4; |
| /* 4.1.2.1: ... PCI Device ID calculated by adding 0x1040 ... */ |
| pci->device_id = 0x1040 + type; |
| |
| /* |
| * PCI have specific codes for different types of devices. |
| * Linux doesn't care, but it's a good clue for people looking |
| * at the device. |
| */ |
| pci->class = class; |
| pci->subclass = subclass; |
| |
| /* |
| * 4.1.2.1: |
| * |
| * Non-transitional devices SHOULD have a PCI Revision ID of 1 or |
| * higher |
| */ |
| pci->revid = 1; |
| |
| /* |
| * 4.1.2.1: |
| * |
| * Non-transitional devices SHOULD have a PCI Subsystem Device ID of |
| * 0x40 or higher. |
| */ |
| pci->subsystem_device_id = 0x40; |
| |
| /* We use our dummy interrupt controller, and irq_line is the irq */ |
| pci->irq_line = devices.next_irq++; |
| pci->irq_pin = 0; |
| |
| /* Support for extended capabilities. */ |
| pci->status = (1 << 4); |
| |
| /* Link them in. */ |
| /* |
| * 4.1.4.3.1: |
| * |
| * The device MUST present at least one common configuration |
| * capability. |
| */ |
| pci->capabilities = offsetof(struct pci_config, common); |
| |
| /* 4.1.4.3.1 ... offset MUST be 4-byte aligned. */ |
| assert(pci->capabilities % 4 == 0); |
| |
| bar_offset = offsetof(struct virtio_pci_mmio, cfg); |
| bar_len = sizeof(((struct virtio_pci_mmio *)0)->cfg); |
| init_cap(&pci->common, sizeof(pci->common), VIRTIO_PCI_CAP_COMMON_CFG, |
| bar_offset, bar_len, |
| offsetof(struct pci_config, notify)); |
| |
| /* |
| * 4.1.4.4.1: |
| * |
| * The device MUST present at least one notification capability. |
| */ |
| bar_offset += bar_len; |
| bar_len = sizeof(((struct virtio_pci_mmio *)0)->notify); |
| |
| /* |
| * 4.1.4.4.1: |
| * |
| * The cap.offset MUST be 2-byte aligned. |
| */ |
| assert(pci->common.cap_next % 2 == 0); |
| |
| /* FIXME: Use a non-zero notify_off, for per-queue notification? */ |
| /* |
| * 4.1.4.4.1: |
| * |
| * The value cap.length presented by the device MUST be at least 2 and |
| * MUST be large enough to support queue notification offsets for all |
| * supported queues in all possible configurations. |
| */ |
| assert(bar_len >= 2); |
| |
| init_cap(&pci->notify.cap, sizeof(pci->notify), |
| VIRTIO_PCI_CAP_NOTIFY_CFG, |
| bar_offset, bar_len, |
| offsetof(struct pci_config, isr)); |
| |
| bar_offset += bar_len; |
| bar_len = sizeof(((struct virtio_pci_mmio *)0)->isr); |
| /* |
| * 4.1.4.5.1: |
| * |
| * The device MUST present at least one VIRTIO_PCI_CAP_ISR_CFG |
| * capability. |
| */ |
| init_cap(&pci->isr, sizeof(pci->isr), |
| VIRTIO_PCI_CAP_ISR_CFG, |
| bar_offset, bar_len, |
| offsetof(struct pci_config, cfg_access)); |
| |
| /* |
| * 4.1.4.7.1: |
| * |
| * The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG |
| * capability. |
| */ |
| /* This doesn't have any presence in the BAR */ |
| init_cap(&pci->cfg_access.cap, sizeof(pci->cfg_access), |
| VIRTIO_PCI_CAP_PCI_CFG, |
| 0, 0, 0); |
| |
| bar_offset += bar_len + sizeof(((struct virtio_pci_mmio *)0)->padding); |
| assert(bar_offset == sizeof(struct virtio_pci_mmio)); |
| |
| /* |
| * This gets sewn in and length set in set_device_config(). |
| * Some devices don't have a device configuration interface, so |
| * we never expose this if we don't call set_device_config(). |
| */ |
| init_cap(&pci->device, sizeof(pci->device), VIRTIO_PCI_CAP_DEVICE_CFG, |
| bar_offset, 0, 0); |
| } |
| |
| /* |
| * This routine does all the creation and setup of a new device, but we don't |
| * actually place the MMIO region until we know the size (if any) of the |
| * device-specific config. And we don't actually start the service threads |
| * until later. |
| * |
| * See what I mean about userspace being boring? |
| */ |
| static struct device *new_pci_device(const char *name, u16 type, |
| u8 class, u8 subclass) |
| { |
| struct device *dev = malloc(sizeof(*dev)); |
| |
| /* Now we populate the fields one at a time. */ |
| dev->name = name; |
| dev->vq = NULL; |
| dev->running = false; |
| dev->wrote_features_ok = false; |
| dev->mmio_size = sizeof(struct virtio_pci_mmio); |
| dev->mmio = calloc(1, dev->mmio_size); |
| dev->features = (u64)1 << VIRTIO_F_VERSION_1; |
| dev->features_accepted = 0; |
| |
| if (devices.device_num + 1 >= MAX_PCI_DEVICES) |
| errx(1, "Can only handle 31 PCI devices"); |
| |
| init_pci_config(&dev->config, type, class, subclass); |
| assert(!devices.pci[devices.device_num+1]); |
| devices.pci[++devices.device_num] = dev; |
| |
| return dev; |
| } |
| |
| /* |
| * Our first setup routine is the console. It's a fairly simple device, but |
| * UNIX tty handling makes it uglier than it could be. |
| */ |
| static void setup_console(void) |
| { |
| struct device *dev; |
| struct virtio_console_config conf; |
| |
| /* If we can save the initial standard input settings... */ |
| if (tcgetattr(STDIN_FILENO, &orig_term) == 0) { |
| struct termios term = orig_term; |
| /* |
| * Then we turn off echo, line buffering and ^C etc: We want a |
| * raw input stream to the Guest. |
| */ |
| term.c_lflag &= ~(ISIG|ICANON|ECHO); |
| tcsetattr(STDIN_FILENO, TCSANOW, &term); |
| } |
| |
| dev = new_pci_device("console", VIRTIO_ID_CONSOLE, 0x07, 0x00); |
| |
| /* We store the console state in dev->priv, and initialize it. */ |
| dev->priv = malloc(sizeof(struct console_abort)); |
| ((struct console_abort *)dev->priv)->count = 0; |
| |
| /* |
| * The console needs two virtqueues: the input then the output. When |
| * they put something the input queue, we make sure we're listening to |
| * stdin. When they put something in the output queue, we write it to |
| * stdout. |
| */ |
| add_pci_virtqueue(dev, console_input, "input"); |
| add_pci_virtqueue(dev, console_output, "output"); |
| |
| /* We need a configuration area for the emerg_wr early writes. */ |
| add_pci_feature(dev, VIRTIO_CONSOLE_F_EMERG_WRITE); |
| set_device_config(dev, &conf, sizeof(conf)); |
| |
| verbose("device %u: console\n", devices.device_num); |
| } |
| /*:*/ |
| |
| /*M:010 |
| * Inter-guest networking is an interesting area. Simplest is to have a |
| * --sharenet=<name> option which opens or creates a named pipe. This can be |
| * used to send packets to another guest in a 1:1 manner. |
| * |
| * More sophisticated is to use one of the tools developed for project like UML |
| * to do networking. |
| * |
| * Faster is to do virtio bonding in kernel. Doing this 1:1 would be |
| * completely generic ("here's my vring, attach to your vring") and would work |
| * for any traffic. Of course, namespace and permissions issues need to be |
| * dealt with. A more sophisticated "multi-channel" virtio_net.c could hide |
| * multiple inter-guest channels behind one interface, although it would |
| * require some manner of hotplugging new virtio channels. |
| * |
| * Finally, we could use a virtio network switch in the kernel, ie. vhost. |
| :*/ |
| |
| static u32 str2ip(const char *ipaddr) |
| { |
| unsigned int b[4]; |
| |
| if (sscanf(ipaddr, "%u.%u.%u.%u", &b[0], &b[1], &b[2], &b[3]) != 4) |
| errx(1, "Failed to parse IP address '%s'", ipaddr); |
| return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3]; |
| } |
| |
| static void str2mac(const char *macaddr, unsigned char mac[6]) |
| { |
| unsigned int m[6]; |
| if (sscanf(macaddr, "%02x:%02x:%02x:%02x:%02x:%02x", |
| &m[0], &m[1], &m[2], &m[3], &m[4], &m[5]) != 6) |
| errx(1, "Failed to parse mac address '%s'", macaddr); |
| mac[0] = m[0]; |
| mac[1] = m[1]; |
| mac[2] = m[2]; |
| mac[3] = m[3]; |
| mac[4] = m[4]; |
| mac[5] = m[5]; |
| } |
| |
| /* |
| * This code is "adapted" from libbridge: it attaches the Host end of the |
| * network device to the bridge device specified by the command line. |
| * |
| * This is yet another James Morris contribution (I'm an IP-level guy, so I |
| * dislike bridging), and I just try not to break it. |
| */ |
| static void add_to_bridge(int fd, const char *if_name, const char *br_name) |
| { |
| int ifidx; |
| struct ifreq ifr; |
| |
| if (!*br_name) |
| errx(1, "must specify bridge name"); |
| |
| ifidx = if_nametoindex(if_name); |
| if (!ifidx) |
| errx(1, "interface %s does not exist!", if_name); |
| |
| strncpy(ifr.ifr_name, br_name, IFNAMSIZ); |
| ifr.ifr_name[IFNAMSIZ-1] = '\0'; |
| ifr.ifr_ifindex = ifidx; |
| if (ioctl(fd, SIOCBRADDIF, &ifr) < 0) |
| err(1, "can't add %s to bridge %s", if_name, br_name); |
| } |
| |
| /* |
| * This sets up the Host end of the network device with an IP address, brings |
| * it up so packets will flow, the copies the MAC address into the hwaddr |
| * pointer. |
| */ |
| static void configure_device(int fd, const char *tapif, u32 ipaddr) |
| { |
| struct ifreq ifr; |
| struct sockaddr_in sin; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strcpy(ifr.ifr_name, tapif); |
| |
| /* Don't read these incantations. Just cut & paste them like I did! */ |
| sin.sin_family = AF_INET; |
| sin.sin_addr.s_addr = htonl(ipaddr); |
| memcpy(&ifr.ifr_addr, &sin, sizeof(sin)); |
| if (ioctl(fd, SIOCSIFADDR, &ifr) != 0) |
| err(1, "Setting %s interface address", tapif); |
| ifr.ifr_flags = IFF_UP; |
| if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0) |
| err(1, "Bringing interface %s up", tapif); |
| } |
| |
| static int get_tun_device(char tapif[IFNAMSIZ]) |
| { |
| struct ifreq ifr; |
| int vnet_hdr_sz; |
| int netfd; |
| |
| /* Start with this zeroed. Messy but sure. */ |
| memset(&ifr, 0, sizeof(ifr)); |
| |
| /* |
| * We open the /dev/net/tun device and tell it we want a tap device. A |
| * tap device is like a tun device, only somehow different. To tell |
| * the truth, I completely blundered my way through this code, but it |
| * works now! |
| */ |
| netfd = open_or_die("/dev/net/tun", O_RDWR); |
| ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR; |
| strcpy(ifr.ifr_name, "tap%d"); |
| if (ioctl(netfd, TUNSETIFF, &ifr) != 0) |
| err(1, "configuring /dev/net/tun"); |
| |
| if (ioctl(netfd, TUNSETOFFLOAD, |
| TUN_F_CSUM|TUN_F_TSO4|TUN_F_TSO6|TUN_F_TSO_ECN) != 0) |
| err(1, "Could not set features for tun device"); |
| |
| /* |
| * We don't need checksums calculated for packets coming in this |
| * device: trust us! |
| */ |
| ioctl(netfd, TUNSETNOCSUM, 1); |
| |
| /* |
| * In virtio before 1.0 (aka legacy virtio), we added a 16-bit |
| * field at the end of the network header iff |
| * VIRTIO_NET_F_MRG_RXBUF was negotiated. For virtio 1.0, |
| * that became the norm, but we need to tell the tun device |
| * about our expanded header (which is called |
| * virtio_net_hdr_mrg_rxbuf in the legacy system). |
| */ |
| vnet_hdr_sz = sizeof(struct virtio_net_hdr_v1); |
| if (ioctl(netfd, TUNSETVNETHDRSZ, &vnet_hdr_sz) != 0) |
| err(1, "Setting tun header size to %u", vnet_hdr_sz); |
| |
| memcpy(tapif, ifr.ifr_name, IFNAMSIZ); |
| return netfd; |
| } |
| |
| /*L:195 |
| * Our network is a Host<->Guest network. This can either use bridging or |
| * routing, but the principle is the same: it uses the "tun" device to inject |
| * packets into the Host as if they came in from a normal network card. We |
| * just shunt packets between the Guest and the tun device. |
| */ |
| static void setup_tun_net(char *arg) |
| { |
| struct device *dev; |
| struct net_info *net_info = malloc(sizeof(*net_info)); |
| int ipfd; |
| u32 ip = INADDR_ANY; |
| bool bridging = false; |
| char tapif[IFNAMSIZ], *p; |
| struct virtio_net_config conf; |
| |
| net_info->tunfd = get_tun_device(tapif); |
| |
| /* First we create a new network device. */ |
| dev = new_pci_device("net", VIRTIO_ID_NET, 0x02, 0x00); |
| dev->priv = net_info; |
| |
| /* Network devices need a recv and a send queue, just like console. */ |
| add_pci_virtqueue(dev, net_input, "rx"); |
| add_pci_virtqueue(dev, net_output, "tx"); |
| |
| /* |
| * We need a socket to perform the magic network ioctls to bring up the |
| * tap interface, connect to the bridge etc. Any socket will do! |
| */ |
| ipfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP); |
| if (ipfd < 0) |
| err(1, "opening IP socket"); |
| |
| /* If the command line was --tunnet=bridge:<name> do bridging. */ |
| if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) { |
| arg += strlen(BRIDGE_PFX); |
| bridging = true; |
| } |
| |
| /* A mac address may follow the bridge name or IP address */ |
| p = strchr(arg, ':'); |
| if (p) { |
| str2mac(p+1, conf.mac); |
| add_pci_feature(dev, VIRTIO_NET_F_MAC); |
| *p = '\0'; |
| } |
| |
| /* arg is now either an IP address or a bridge name */ |
| if (bridging) |
| add_to_bridge(ipfd, tapif, arg); |
| else |
| ip = str2ip(arg); |
| |
| /* Set up the tun device. */ |
| configure_device(ipfd, tapif, ip); |
| |
| /* Expect Guest to handle everything except UFO */ |
| add_pci_feature(dev, VIRTIO_NET_F_CSUM); |
| add_pci_feature(dev, VIRTIO_NET_F_GUEST_CSUM); |
| add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO4); |
| add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO6); |
| add_pci_feature(dev, VIRTIO_NET_F_GUEST_ECN); |
| add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO4); |
| add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO6); |
| add_pci_feature(dev, VIRTIO_NET_F_HOST_ECN); |
| /* We handle indirect ring entries */ |
| add_pci_feature(dev, VIRTIO_RING_F_INDIRECT_DESC); |
| set_device_config(dev, &conf, sizeof(conf)); |
| |
| /* We don't need the socket any more; setup is done. */ |
| close(ipfd); |
| |
| if (bridging) |
| verbose("device %u: tun %s attached to bridge: %s\n", |
| devices.device_num, tapif, arg); |
| else |
| verbose("device %u: tun %s: %s\n", |
| devices.device_num, tapif, arg); |
| } |
| /*:*/ |
| |
| /* This hangs off device->priv. */ |
| struct vblk_info { |
| /* The size of the file. */ |
| off64_t len; |
| |
| /* The file descriptor for the file. */ |
| int fd; |
| |
| }; |
| |
| /*L:210 |
| * The Disk |
| * |
| * The disk only has one virtqueue, so it only has one thread. It is really |
| * simple: the Guest asks for a block number and we read or write that position |
| * in the file. |
| * |
| * Before we serviced each virtqueue in a separate thread, that was unacceptably |
| * slow: the Guest waits until the read is finished before running anything |
| * else, even if it could have been doing useful work. |
| * |
| * We could have used async I/O, except it's reputed to suck so hard that |
| * characters actually go missing from your code when you try to use it. |
| */ |
| static void blk_request(struct virtqueue *vq) |
| { |
| struct vblk_info *vblk = vq->dev->priv; |
| unsigned int head, out_num, in_num, wlen; |
| int ret, i; |
| u8 *in; |
| struct virtio_blk_outhdr out; |
| struct iovec iov[vq->vring.num]; |
| off64_t off; |
| |
| /* |
| * Get the next request, where we normally wait. It triggers the |
| * interrupt to acknowledge previously serviced requests (if any). |
| */ |
| head = wait_for_vq_desc(vq, iov, &out_num, &in_num); |
| |
| /* Copy the output header from the front of the iov (adjusts iov) */ |
| iov_consume(vq->dev, iov, out_num, &out, sizeof(out)); |
| |
| /* Find and trim end of iov input array, for our status byte. */ |
| in = NULL; |
| for (i = out_num + in_num - 1; i >= out_num; i--) { |
| if (iov[i].iov_len > 0) { |
| in = iov[i].iov_base + iov[i].iov_len - 1; |
| iov[i].iov_len--; |
| break; |
| } |
| } |
| if (!in) |
| bad_driver_vq(vq, "Bad virtblk cmd with no room for status"); |
| |
| /* |
| * For historical reasons, block operations are expressed in 512 byte |
| * "sectors". |
| */ |
| off = out.sector * 512; |
| |
| if (out.type & VIRTIO_BLK_T_OUT) { |
| /* |
| * Write |
| * |
| * Move to the right location in the block file. This can fail |
| * if they try to write past end. |
| */ |
| if (lseek64(vblk->fd, off, SEEK_SET) != off) |
| err(1, "Bad seek to sector %llu", out.sector); |
| |
| ret = writev(vblk->fd, iov, out_num); |
| verbose("WRITE to sector %llu: %i\n", out.sector, ret); |
| |
| /* |
| * Grr... Now we know how long the descriptor they sent was, we |
| * make sure they didn't try to write over the end of the block |
| * file (possibly extending it). |
| */ |
| if (ret > 0 && off + ret > vblk->len) { |
| /* Trim it back to the correct length */ |
| ftruncate64(vblk->fd, vblk->len); |
| /* Die, bad Guest, die. */ |
| bad_driver_vq(vq, "Write past end %llu+%u", off, ret); |
| } |
| |
| wlen = sizeof(*in); |
| *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); |
| } else if (out.type & VIRTIO_BLK_T_FLUSH) { |
| /* Flush */ |
| ret = fdatasync(vblk->fd); |
| verbose("FLUSH fdatasync: %i\n", ret); |
| wlen = sizeof(*in); |
| *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); |
| } else { |
| /* |
| * Read |
| * |
| * Move to the right location in the block file. This can fail |
| * if they try to read past end. |
| */ |
| if (lseek64(vblk->fd, off, SEEK_SET) != off) |
| err(1, "Bad seek to sector %llu", out.sector); |
| |
| ret = readv(vblk->fd, iov + out_num, in_num); |
| if (ret >= 0) { |
| wlen = sizeof(*in) + ret; |
| *in = VIRTIO_BLK_S_OK; |
| } else { |
| wlen = sizeof(*in); |
| *in = VIRTIO_BLK_S_IOERR; |
| } |
| } |
| |
| /* Finished that request. */ |
| add_used(vq, head, wlen); |
| } |
| |
| /*L:198 This actually sets up a virtual block device. */ |
| static void setup_block_file(const char *filename) |
| { |
| struct device *dev; |
| struct vblk_info *vblk; |
| struct virtio_blk_config conf; |
| |
| /* Create the device. */ |
| dev = new_pci_device("block", VIRTIO_ID_BLOCK, 0x01, 0x80); |
| |
| /* The device has one virtqueue, where the Guest places requests. */ |
| add_pci_virtqueue(dev, blk_request, "request"); |
| |
| /* Allocate the room for our own bookkeeping */ |
| vblk = dev->priv = malloc(sizeof(*vblk)); |
| |
| /* First we open the file and store the length. */ |
| vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); |
| vblk->len = lseek64(vblk->fd, 0, SEEK_END); |
| |
| /* Tell Guest how many sectors this device has. */ |
| conf.capacity = cpu_to_le64(vblk->len / 512); |
| |
| /* |
| * Tell Guest not to put in too many descriptors at once: two are used |
| * for the in and out elements. |
| */ |
| add_pci_feature(dev, VIRTIO_BLK_F_SEG_MAX); |
| conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2); |
| |
| set_device_config(dev, &conf, sizeof(struct virtio_blk_config)); |
| |
| verbose("device %u: virtblock %llu sectors\n", |
| devices.device_num, le64_to_cpu(conf.capacity)); |
| } |
| |
| /*L:211 |
| * Our random number generator device reads from /dev/urandom into the Guest's |
| * input buffers. The usual case is that the Guest doesn't want random numbers |
| * and so has no buffers although /dev/urandom is still readable, whereas |
| * console is the reverse. |
| * |
| * The same logic applies, however. |
| */ |
| struct rng_info { |
| int rfd; |
| }; |
| |
| static void rng_input(struct virtqueue *vq) |
| { |
| int len; |
| unsigned int head, in_num, out_num, totlen = 0; |
| struct rng_info *rng_info = vq->dev->priv; |
| struct iovec iov[vq->vring.num]; |
| |
| /* First we need a buffer from the Guests's virtqueue. */ |
| head = wait_for_vq_desc(vq, iov, &out_num, &in_num); |
| if (out_num) |
| bad_driver_vq(vq, "Output buffers in rng?"); |
| |
| /* |
| * Just like the console write, we loop to cover the whole iovec. |
| * In this case, short reads actually happen quite a bit. |
| */ |
| while (!iov_empty(iov, in_num)) { |
| len = readv(rng_info->rfd, iov, in_num); |
| if (len <= 0) |
| err(1, "Read from /dev/urandom gave %i", len); |
| iov_consume(vq->dev, iov, in_num, NULL, len); |
| totlen += len; |
| } |
| |
| /* Tell the Guest about the new input. */ |
| add_used(vq, head, totlen); |
| } |
| |
| /*L:199 |
| * This creates a "hardware" random number device for the Guest. |
| */ |
| static void setup_rng(void) |
| { |
| struct device *dev; |
| struct rng_info *rng_info = malloc(sizeof(*rng_info)); |
| |
| /* Our device's private info simply contains the /dev/urandom fd. */ |
| rng_info->rfd = open_or_die("/dev/urandom", O_RDONLY); |
| |
| /* Create the new device. */ |
| dev = new_pci_device("rng", VIRTIO_ID_RNG, 0xff, 0); |
| dev->priv = rng_info; |
| |
| /* The device has one virtqueue, where the Guest places inbufs. */ |
| add_pci_virtqueue(dev, rng_input, "input"); |
| |
| /* We don't have any configuration space */ |
| no_device_config(dev); |
| |
| verbose("device %u: rng\n", devices.device_num); |
| } |
| /* That's the end of device setup. */ |
| |
| /*L:230 Reboot is pretty easy: clean up and exec() the Launcher afresh. */ |
| static void __attribute__((noreturn)) restart_guest(void) |
| { |
| unsigned int i; |
| |
| /* |
| * Since we don't track all open fds, we simply close everything beyond |
| * stderr. |
| */ |
| for (i = 3; i < FD_SETSIZE; i++) |
| close(i); |
| |
| /* Reset all the devices (kills all threads). */ |
| cleanup_devices(); |
| |
| execv(main_args[0], main_args); |
| err(1, "Could not exec %s", main_args[0]); |
| } |
| |
| /*L:220 |
| * Finally we reach the core of the Launcher which runs the Guest, serves |
| * its input and output, and finally, lays it to rest. |
| */ |
| static void __attribute__((noreturn)) run_guest(void) |
| { |
| for (;;) { |
| struct lguest_pending notify; |
| int readval; |
| |
| /* We read from the /dev/lguest device to run the Guest. */ |
|