| /****************************************************************************** |
| * grant_table.c |
| * |
| * Granting foreign access to our memory reservation. |
| * |
| * Copyright (c) 2005-2006, Christopher Clark |
| * Copyright (c) 2004-2005, K A Fraser |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License version 2 |
| * as published by the Free Software Foundation; or, when distributed |
| * separately from the Linux kernel or incorporated into other |
| * software packages, subject to the following license: |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this source file (the "Software"), to deal in the Software without |
| * restriction, including without limitation the rights to use, copy, modify, |
| * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, subject to |
| * the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| #include <linux/uaccess.h> |
| #include <linux/io.h> |
| #include <linux/hardirq.h> |
| |
| #include <xen/xen.h> |
| #include <xen/interface/xen.h> |
| #include <xen/page.h> |
| #include <xen/grant_table.h> |
| #include <xen/interface/memory.h> |
| #include <xen/hvc-console.h> |
| #include <asm/xen/hypercall.h> |
| |
| #include <asm/pgtable.h> |
| #include <asm/sync_bitops.h> |
| |
| /* External tools reserve first few grant table entries. */ |
| #define NR_RESERVED_ENTRIES 8 |
| #define GNTTAB_LIST_END 0xffffffff |
| #define GREFS_PER_GRANT_FRAME \ |
| (grant_table_version == 1 ? \ |
| (PAGE_SIZE / sizeof(struct grant_entry_v1)) : \ |
| (PAGE_SIZE / sizeof(union grant_entry_v2))) |
| |
| static grant_ref_t **gnttab_list; |
| static unsigned int nr_grant_frames; |
| static unsigned int boot_max_nr_grant_frames; |
| static int gnttab_free_count; |
| static grant_ref_t gnttab_free_head; |
| static DEFINE_SPINLOCK(gnttab_list_lock); |
| unsigned long xen_hvm_resume_frames; |
| EXPORT_SYMBOL_GPL(xen_hvm_resume_frames); |
| |
| static union { |
| struct grant_entry_v1 *v1; |
| union grant_entry_v2 *v2; |
| void *addr; |
| } gnttab_shared; |
| |
| /*This is a structure of function pointers for grant table*/ |
| struct gnttab_ops { |
| /* |
| * Mapping a list of frames for storing grant entries. Frames parameter |
| * is used to store grant table address when grant table being setup, |
| * nr_gframes is the number of frames to map grant table. Returning |
| * GNTST_okay means success and negative value means failure. |
| */ |
| int (*map_frames)(unsigned long *frames, unsigned int nr_gframes); |
| /* |
| * Release a list of frames which are mapped in map_frames for grant |
| * entry status. |
| */ |
| void (*unmap_frames)(void); |
| /* |
| * Introducing a valid entry into the grant table, granting the frame of |
| * this grant entry to domain for accessing or transfering. Ref |
| * parameter is reference of this introduced grant entry, domid is id of |
| * granted domain, frame is the page frame to be granted, and flags is |
| * status of the grant entry to be updated. |
| */ |
| void (*update_entry)(grant_ref_t ref, domid_t domid, |
| unsigned long frame, unsigned flags); |
| /* |
| * Stop granting a grant entry to domain for accessing. Ref parameter is |
| * reference of a grant entry whose grant access will be stopped, |
| * readonly is not in use in this function. If the grant entry is |
| * currently mapped for reading or writing, just return failure(==0) |
| * directly and don't tear down the grant access. Otherwise, stop grant |
| * access for this entry and return success(==1). |
| */ |
| int (*end_foreign_access_ref)(grant_ref_t ref, int readonly); |
| /* |
| * Stop granting a grant entry to domain for transfer. Ref parameter is |
| * reference of a grant entry whose grant transfer will be stopped. If |
| * tranfer has not started, just reclaim the grant entry and return |
| * failure(==0). Otherwise, wait for the transfer to complete and then |
| * return the frame. |
| */ |
| unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref); |
| /* |
| * Query the status of a grant entry. Ref parameter is reference of |
| * queried grant entry, return value is the status of queried entry. |
| * Detailed status(writing/reading) can be gotten from the return value |
| * by bit operations. |
| */ |
| int (*query_foreign_access)(grant_ref_t ref); |
| /* |
| * Grant a domain to access a range of bytes within the page referred by |
| * an available grant entry. Ref parameter is reference of a grant entry |
| * which will be sub-page accessed, domid is id of grantee domain, frame |
| * is frame address of subpage grant, flags is grant type and flag |
| * information, page_off is offset of the range of bytes, and length is |
| * length of bytes to be accessed. |
| */ |
| void (*update_subpage_entry)(grant_ref_t ref, domid_t domid, |
| unsigned long frame, int flags, |
| unsigned page_off, unsigned length); |
| /* |
| * Redirect an available grant entry on domain A to another grant |
| * reference of domain B, then allow domain C to use grant reference |
| * of domain B transitively. Ref parameter is an available grant entry |
| * reference on domain A, domid is id of domain C which accesses grant |
| * entry transitively, flags is grant type and flag information, |
| * trans_domid is id of domain B whose grant entry is finally accessed |
| * transitively, trans_gref is grant entry transitive reference of |
| * domain B. |
| */ |
| void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags, |
| domid_t trans_domid, grant_ref_t trans_gref); |
| }; |
| |
| static struct gnttab_ops *gnttab_interface; |
| |
| /*This reflects status of grant entries, so act as a global value*/ |
| static grant_status_t *grstatus; |
| |
| static int grant_table_version; |
| |
| static struct gnttab_free_callback *gnttab_free_callback_list; |
| |
| static int gnttab_expand(unsigned int req_entries); |
| |
| #define RPP (PAGE_SIZE / sizeof(grant_ref_t)) |
| #define SPP (PAGE_SIZE / sizeof(grant_status_t)) |
| |
| static inline grant_ref_t *__gnttab_entry(grant_ref_t entry) |
| { |
| return &gnttab_list[(entry) / RPP][(entry) % RPP]; |
| } |
| /* This can be used as an l-value */ |
| #define gnttab_entry(entry) (*__gnttab_entry(entry)) |
| |
| static int get_free_entries(unsigned count) |
| { |
| unsigned long flags; |
| int ref, rc = 0; |
| grant_ref_t head; |
| |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| |
| if ((gnttab_free_count < count) && |
| ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) { |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| return rc; |
| } |
| |
| ref = head = gnttab_free_head; |
| gnttab_free_count -= count; |
| while (count-- > 1) |
| head = gnttab_entry(head); |
| gnttab_free_head = gnttab_entry(head); |
| gnttab_entry(head) = GNTTAB_LIST_END; |
| |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| |
| return ref; |
| } |
| |
| static void do_free_callbacks(void) |
| { |
| struct gnttab_free_callback *callback, *next; |
| |
| callback = gnttab_free_callback_list; |
| gnttab_free_callback_list = NULL; |
| |
| while (callback != NULL) { |
| next = callback->next; |
| if (gnttab_free_count >= callback->count) { |
| callback->next = NULL; |
| callback->fn(callback->arg); |
| } else { |
| callback->next = gnttab_free_callback_list; |
| gnttab_free_callback_list = callback; |
| } |
| callback = next; |
| } |
| } |
| |
| static inline void check_free_callbacks(void) |
| { |
| if (unlikely(gnttab_free_callback_list)) |
| do_free_callbacks(); |
| } |
| |
| static void put_free_entry(grant_ref_t ref) |
| { |
| unsigned long flags; |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| gnttab_entry(ref) = gnttab_free_head; |
| gnttab_free_head = ref; |
| gnttab_free_count++; |
| check_free_callbacks(); |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| } |
| |
| /* |
| * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2. |
| * Introducing a valid entry into the grant table: |
| * 1. Write ent->domid. |
| * 2. Write ent->frame: |
| * GTF_permit_access: Frame to which access is permitted. |
| * GTF_accept_transfer: Pseudo-phys frame slot being filled by new |
| * frame, or zero if none. |
| * 3. Write memory barrier (WMB). |
| * 4. Write ent->flags, inc. valid type. |
| */ |
| static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid, |
| unsigned long frame, unsigned flags) |
| { |
| gnttab_shared.v1[ref].domid = domid; |
| gnttab_shared.v1[ref].frame = frame; |
| wmb(); |
| gnttab_shared.v1[ref].flags = flags; |
| } |
| |
| static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid, |
| unsigned long frame, unsigned flags) |
| { |
| gnttab_shared.v2[ref].hdr.domid = domid; |
| gnttab_shared.v2[ref].full_page.frame = frame; |
| wmb(); |
| gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags; |
| } |
| |
| /* |
| * Public grant-issuing interface functions |
| */ |
| void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid, |
| unsigned long frame, int readonly) |
| { |
| gnttab_interface->update_entry(ref, domid, frame, |
| GTF_permit_access | (readonly ? GTF_readonly : 0)); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref); |
| |
| int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, |
| int readonly) |
| { |
| int ref; |
| |
| ref = get_free_entries(1); |
| if (unlikely(ref < 0)) |
| return -ENOSPC; |
| |
| gnttab_grant_foreign_access_ref(ref, domid, frame, readonly); |
| |
| return ref; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access); |
| |
| void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid, |
| unsigned long frame, int flags, |
| unsigned page_off, |
| unsigned length) |
| { |
| gnttab_shared.v2[ref].sub_page.frame = frame; |
| gnttab_shared.v2[ref].sub_page.page_off = page_off; |
| gnttab_shared.v2[ref].sub_page.length = length; |
| gnttab_shared.v2[ref].hdr.domid = domid; |
| wmb(); |
| gnttab_shared.v2[ref].hdr.flags = |
| GTF_permit_access | GTF_sub_page | flags; |
| } |
| |
| int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid, |
| unsigned long frame, int flags, |
| unsigned page_off, |
| unsigned length) |
| { |
| if (flags & (GTF_accept_transfer | GTF_reading | |
| GTF_writing | GTF_transitive)) |
| return -EPERM; |
| |
| if (gnttab_interface->update_subpage_entry == NULL) |
| return -ENOSYS; |
| |
| gnttab_interface->update_subpage_entry(ref, domid, frame, flags, |
| page_off, length); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref); |
| |
| int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame, |
| int flags, unsigned page_off, |
| unsigned length) |
| { |
| int ref, rc; |
| |
| ref = get_free_entries(1); |
| if (unlikely(ref < 0)) |
| return -ENOSPC; |
| |
| rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags, |
| page_off, length); |
| if (rc < 0) { |
| put_free_entry(ref); |
| return rc; |
| } |
| |
| return ref; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage); |
| |
| bool gnttab_subpage_grants_available(void) |
| { |
| return gnttab_interface->update_subpage_entry != NULL; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available); |
| |
| void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid, |
| int flags, domid_t trans_domid, |
| grant_ref_t trans_gref) |
| { |
| gnttab_shared.v2[ref].transitive.trans_domid = trans_domid; |
| gnttab_shared.v2[ref].transitive.gref = trans_gref; |
| gnttab_shared.v2[ref].hdr.domid = domid; |
| wmb(); |
| gnttab_shared.v2[ref].hdr.flags = |
| GTF_permit_access | GTF_transitive | flags; |
| } |
| |
| int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid, |
| int flags, domid_t trans_domid, |
| grant_ref_t trans_gref) |
| { |
| if (flags & (GTF_accept_transfer | GTF_reading | |
| GTF_writing | GTF_sub_page)) |
| return -EPERM; |
| |
| if (gnttab_interface->update_trans_entry == NULL) |
| return -ENOSYS; |
| |
| gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid, |
| trans_gref); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref); |
| |
| int gnttab_grant_foreign_access_trans(domid_t domid, int flags, |
| domid_t trans_domid, |
| grant_ref_t trans_gref) |
| { |
| int ref, rc; |
| |
| ref = get_free_entries(1); |
| if (unlikely(ref < 0)) |
| return -ENOSPC; |
| |
| rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags, |
| trans_domid, trans_gref); |
| if (rc < 0) { |
| put_free_entry(ref); |
| return rc; |
| } |
| |
| return ref; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans); |
| |
| bool gnttab_trans_grants_available(void) |
| { |
| return gnttab_interface->update_trans_entry != NULL; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_trans_grants_available); |
| |
| static int gnttab_query_foreign_access_v1(grant_ref_t ref) |
| { |
| return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing); |
| } |
| |
| static int gnttab_query_foreign_access_v2(grant_ref_t ref) |
| { |
| return grstatus[ref] & (GTF_reading|GTF_writing); |
| } |
| |
| int gnttab_query_foreign_access(grant_ref_t ref) |
| { |
| return gnttab_interface->query_foreign_access(ref); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_query_foreign_access); |
| |
| static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly) |
| { |
| u16 flags, nflags; |
| u16 *pflags; |
| |
| pflags = &gnttab_shared.v1[ref].flags; |
| nflags = *pflags; |
| do { |
| flags = nflags; |
| if (flags & (GTF_reading|GTF_writing)) |
| return 0; |
| } while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags); |
| |
| return 1; |
| } |
| |
| static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly) |
| { |
| gnttab_shared.v2[ref].hdr.flags = 0; |
| mb(); |
| if (grstatus[ref] & (GTF_reading|GTF_writing)) { |
| return 0; |
| } else { |
| /* The read of grstatus needs to have acquire |
| semantics. On x86, reads already have |
| that, and we just need to protect against |
| compiler reorderings. On other |
| architectures we may need a full |
| barrier. */ |
| #ifdef CONFIG_X86 |
| barrier(); |
| #else |
| mb(); |
| #endif |
| } |
| |
| return 1; |
| } |
| |
| static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly) |
| { |
| return gnttab_interface->end_foreign_access_ref(ref, readonly); |
| } |
| |
| int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly) |
| { |
| if (_gnttab_end_foreign_access_ref(ref, readonly)) |
| return 1; |
| pr_warn("WARNING: g.e. %#x still in use!\n", ref); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref); |
| |
| struct deferred_entry { |
| struct list_head list; |
| grant_ref_t ref; |
| bool ro; |
| uint16_t warn_delay; |
| struct page *page; |
| }; |
| static LIST_HEAD(deferred_list); |
| static void gnttab_handle_deferred(unsigned long); |
| static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0); |
| |
| static void gnttab_handle_deferred(unsigned long unused) |
| { |
| unsigned int nr = 10; |
| struct deferred_entry *first = NULL; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| while (nr--) { |
| struct deferred_entry *entry |
| = list_first_entry(&deferred_list, |
| struct deferred_entry, list); |
| |
| if (entry == first) |
| break; |
| list_del(&entry->list); |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) { |
| put_free_entry(entry->ref); |
| if (entry->page) { |
| pr_debug("freeing g.e. %#x (pfn %#lx)\n", |
| entry->ref, page_to_pfn(entry->page)); |
| __free_page(entry->page); |
| } else |
| pr_info("freeing g.e. %#x\n", entry->ref); |
| kfree(entry); |
| entry = NULL; |
| } else { |
| if (!--entry->warn_delay) |
| pr_info("g.e. %#x still pending\n", |
| entry->ref); |
| if (!first) |
| first = entry; |
| } |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| if (entry) |
| list_add_tail(&entry->list, &deferred_list); |
| else if (list_empty(&deferred_list)) |
| break; |
| } |
| if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) { |
| deferred_timer.expires = jiffies + HZ; |
| add_timer(&deferred_timer); |
| } |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| } |
| |
| static void gnttab_add_deferred(grant_ref_t ref, bool readonly, |
| struct page *page) |
| { |
| struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC); |
| const char *what = KERN_WARNING "leaking"; |
| |
| if (entry) { |
| unsigned long flags; |
| |
| entry->ref = ref; |
| entry->ro = readonly; |
| entry->page = page; |
| entry->warn_delay = 60; |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| list_add_tail(&entry->list, &deferred_list); |
| if (!timer_pending(&deferred_timer)) { |
| deferred_timer.expires = jiffies + HZ; |
| add_timer(&deferred_timer); |
| } |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| what = KERN_DEBUG "deferring"; |
| } |
| printk("%s g.e. %#x (pfn %#lx)\n", |
| what, ref, page ? page_to_pfn(page) : -1); |
| } |
| |
| void gnttab_end_foreign_access(grant_ref_t ref, int readonly, |
| unsigned long page) |
| { |
| if (gnttab_end_foreign_access_ref(ref, readonly)) { |
| put_free_entry(ref); |
| if (page != 0) |
| free_page(page); |
| } else |
| gnttab_add_deferred(ref, readonly, |
| page ? virt_to_page(page) : NULL); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_end_foreign_access); |
| |
| int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn) |
| { |
| int ref; |
| |
| ref = get_free_entries(1); |
| if (unlikely(ref < 0)) |
| return -ENOSPC; |
| gnttab_grant_foreign_transfer_ref(ref, domid, pfn); |
| |
| return ref; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer); |
| |
| void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid, |
| unsigned long pfn) |
| { |
| gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref); |
| |
| static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref) |
| { |
| unsigned long frame; |
| u16 flags; |
| u16 *pflags; |
| |
| pflags = &gnttab_shared.v1[ref].flags; |
| |
| /* |
| * If a transfer is not even yet started, try to reclaim the grant |
| * reference and return failure (== 0). |
| */ |
| while (!((flags = *pflags) & GTF_transfer_committed)) { |
| if (sync_cmpxchg(pflags, flags, 0) == flags) |
| return 0; |
| cpu_relax(); |
| } |
| |
| /* If a transfer is in progress then wait until it is completed. */ |
| while (!(flags & GTF_transfer_completed)) { |
| flags = *pflags; |
| cpu_relax(); |
| } |
| |
| rmb(); /* Read the frame number /after/ reading completion status. */ |
| frame = gnttab_shared.v1[ref].frame; |
| BUG_ON(frame == 0); |
| |
| return frame; |
| } |
| |
| static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref) |
| { |
| unsigned long frame; |
| u16 flags; |
| u16 *pflags; |
| |
| pflags = &gnttab_shared.v2[ref].hdr.flags; |
| |
| /* |
| * If a transfer is not even yet started, try to reclaim the grant |
| * reference and return failure (== 0). |
| */ |
| while (!((flags = *pflags) & GTF_transfer_committed)) { |
| if (sync_cmpxchg(pflags, flags, 0) == flags) |
| return 0; |
| cpu_relax(); |
| } |
| |
| /* If a transfer is in progress then wait until it is completed. */ |
| while (!(flags & GTF_transfer_completed)) { |
| flags = *pflags; |
| cpu_relax(); |
| } |
| |
| rmb(); /* Read the frame number /after/ reading completion status. */ |
| frame = gnttab_shared.v2[ref].full_page.frame; |
| BUG_ON(frame == 0); |
| |
| return frame; |
| } |
| |
| unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref) |
| { |
| return gnttab_interface->end_foreign_transfer_ref(ref); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref); |
| |
| unsigned long gnttab_end_foreign_transfer(grant_ref_t ref) |
| { |
| unsigned long frame = gnttab_end_foreign_transfer_ref(ref); |
| put_free_entry(ref); |
| return frame; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer); |
| |
| void gnttab_free_grant_reference(grant_ref_t ref) |
| { |
| put_free_entry(ref); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_free_grant_reference); |
| |
| void gnttab_free_grant_references(grant_ref_t head) |
| { |
| grant_ref_t ref; |
| unsigned long flags; |
| int count = 1; |
| if (head == GNTTAB_LIST_END) |
| return; |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| ref = head; |
| while (gnttab_entry(ref) != GNTTAB_LIST_END) { |
| ref = gnttab_entry(ref); |
| count++; |
| } |
| gnttab_entry(ref) = gnttab_free_head; |
| gnttab_free_head = head; |
| gnttab_free_count += count; |
| check_free_callbacks(); |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_free_grant_references); |
| |
| int gnttab_alloc_grant_references(u16 count, grant_ref_t *head) |
| { |
| int h = get_free_entries(count); |
| |
| if (h < 0) |
| return -ENOSPC; |
| |
| *head = h; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references); |
| |
| int gnttab_empty_grant_references(const grant_ref_t *private_head) |
| { |
| return (*private_head == GNTTAB_LIST_END); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_empty_grant_references); |
| |
| int gnttab_claim_grant_reference(grant_ref_t *private_head) |
| { |
| grant_ref_t g = *private_head; |
| if (unlikely(g == GNTTAB_LIST_END)) |
| return -ENOSPC; |
| *private_head = gnttab_entry(g); |
| return g; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference); |
| |
| void gnttab_release_grant_reference(grant_ref_t *private_head, |
| grant_ref_t release) |
| { |
| gnttab_entry(release) = *private_head; |
| *private_head = release; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_release_grant_reference); |
| |
| void gnttab_request_free_callback(struct gnttab_free_callback *callback, |
| void (*fn)(void *), void *arg, u16 count) |
| { |
| unsigned long flags; |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| if (callback->next) |
| goto out; |
| callback->fn = fn; |
| callback->arg = arg; |
| callback->count = count; |
| callback->next = gnttab_free_callback_list; |
| gnttab_free_callback_list = callback; |
| check_free_callbacks(); |
| out: |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_request_free_callback); |
| |
| void gnttab_cancel_free_callback(struct gnttab_free_callback *callback) |
| { |
| struct gnttab_free_callback **pcb; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&gnttab_list_lock, flags); |
| for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) { |
| if (*pcb == callback) { |
| *pcb = callback->next; |
| break; |
| } |
| } |
| spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback); |
| |
| static int grow_gnttab_list(unsigned int more_frames) |
| { |
| unsigned int new_nr_grant_frames, extra_entries, i; |
| unsigned int nr_glist_frames, new_nr_glist_frames; |
| |
| new_nr_grant_frames = nr_grant_frames + more_frames; |
| extra_entries = more_frames * GREFS_PER_GRANT_FRAME; |
| |
| nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| new_nr_glist_frames = |
| (new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| for (i = nr_glist_frames; i < new_nr_glist_frames; i++) { |
| gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC); |
| if (!gnttab_list[i]) |
| goto grow_nomem; |
| } |
| |
| |
| for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames; |
| i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++) |
| gnttab_entry(i) = i + 1; |
| |
| gnttab_entry(i) = gnttab_free_head; |
| gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames; |
| gnttab_free_count += extra_entries; |
| |
| nr_grant_frames = new_nr_grant_frames; |
| |
| check_free_callbacks(); |
| |
| return 0; |
| |
| grow_nomem: |
| for ( ; i >= nr_glist_frames; i--) |
| free_page((unsigned long) gnttab_list[i]); |
| return -ENOMEM; |
| } |
| |
| static unsigned int __max_nr_grant_frames(void) |
| { |
| struct gnttab_query_size query; |
| int rc; |
| |
| query.dom = DOMID_SELF; |
| |
| rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1); |
| if ((rc < 0) || (query.status != GNTST_okay)) |
| return 4; /* Legacy max supported number of frames */ |
| |
| return query.max_nr_frames; |
| } |
| |
| unsigned int gnttab_max_grant_frames(void) |
| { |
| unsigned int xen_max = __max_nr_grant_frames(); |
| |
| if (xen_max > boot_max_nr_grant_frames) |
| return boot_max_nr_grant_frames; |
| return xen_max; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_max_grant_frames); |
| |
| int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, |
| struct gnttab_map_grant_ref *kmap_ops, |
| struct page **pages, unsigned int count) |
| { |
| int i, ret; |
| bool lazy = false; |
| pte_t *pte; |
| unsigned long mfn; |
| |
| ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count); |
| if (ret) |
| return ret; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return ret; |
| |
| if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { |
| arch_enter_lazy_mmu_mode(); |
| lazy = true; |
| } |
| |
| for (i = 0; i < count; i++) { |
| /* Do not add to override if the map failed. */ |
| if (map_ops[i].status) |
| continue; |
| |
| if (map_ops[i].flags & GNTMAP_contains_pte) { |
| pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + |
| (map_ops[i].host_addr & ~PAGE_MASK)); |
| mfn = pte_mfn(*pte); |
| } else { |
| mfn = PFN_DOWN(map_ops[i].dev_bus_addr); |
| } |
| ret = m2p_add_override(mfn, pages[i], kmap_ops ? |
| &kmap_ops[i] : NULL); |
| if (ret) |
| return ret; |
| } |
| |
| if (lazy) |
| arch_leave_lazy_mmu_mode(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_map_refs); |
| |
| int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, |
| struct gnttab_map_grant_ref *kmap_ops, |
| struct page **pages, unsigned int count) |
| { |
| int i, ret; |
| bool lazy = false; |
| |
| ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count); |
| if (ret) |
| return ret; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return ret; |
| |
| if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { |
| arch_enter_lazy_mmu_mode(); |
| lazy = true; |
| } |
| |
| for (i = 0; i < count; i++) { |
| ret = m2p_remove_override(pages[i], kmap_ops ? |
| &kmap_ops[i] : NULL); |
| if (ret) |
| return ret; |
| } |
| |
| if (lazy) |
| arch_leave_lazy_mmu_mode(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_unmap_refs); |
| |
| static unsigned nr_status_frames(unsigned nr_grant_frames) |
| { |
| return (nr_grant_frames * GREFS_PER_GRANT_FRAME + SPP - 1) / SPP; |
| } |
| |
| static int gnttab_map_frames_v1(unsigned long *frames, unsigned int nr_gframes) |
| { |
| int rc; |
| |
| rc = arch_gnttab_map_shared(frames, nr_gframes, |
| gnttab_max_grant_frames(), |
| &gnttab_shared.addr); |
| BUG_ON(rc); |
| |
| return 0; |
| } |
| |
| static void gnttab_unmap_frames_v1(void) |
| { |
| arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames); |
| } |
| |
| static int gnttab_map_frames_v2(unsigned long *frames, unsigned int nr_gframes) |
| { |
| uint64_t *sframes; |
| unsigned int nr_sframes; |
| struct gnttab_get_status_frames getframes; |
| int rc; |
| |
| nr_sframes = nr_status_frames(nr_gframes); |
| |
| /* No need for kzalloc as it is initialized in following hypercall |
| * GNTTABOP_get_status_frames. |
| */ |
| sframes = kmalloc(nr_sframes * sizeof(uint64_t), GFP_ATOMIC); |
| if (!sframes) |
| return -ENOMEM; |
| |
| getframes.dom = DOMID_SELF; |
| getframes.nr_frames = nr_sframes; |
| set_xen_guest_handle(getframes.frame_list, sframes); |
| |
| rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames, |
| &getframes, 1); |
| if (rc == -ENOSYS) { |
| kfree(sframes); |
| return -ENOSYS; |
| } |
| |
| BUG_ON(rc || getframes.status); |
| |
| rc = arch_gnttab_map_status(sframes, nr_sframes, |
| nr_status_frames(gnttab_max_grant_frames()), |
| &grstatus); |
| BUG_ON(rc); |
| kfree(sframes); |
| |
| rc = arch_gnttab_map_shared(frames, nr_gframes, |
| gnttab_max_grant_frames(), |
| &gnttab_shared.addr); |
| BUG_ON(rc); |
| |
| return 0; |
| } |
| |
| static void gnttab_unmap_frames_v2(void) |
| { |
| arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames); |
| arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames)); |
| } |
| |
| static int gnttab_map(unsigned int start_idx, unsigned int end_idx) |
| { |
| struct gnttab_setup_table setup; |
| unsigned long *frames; |
| unsigned int nr_gframes = end_idx + 1; |
| int rc; |
| |
| if (xen_hvm_domain()) { |
| struct xen_add_to_physmap xatp; |
| unsigned int i = end_idx; |
| rc = 0; |
| /* |
| * Loop backwards, so that the first hypercall has the largest |
| * index, ensuring that the table will grow only once. |
| */ |
| do { |
| xatp.domid = DOMID_SELF; |
| xatp.idx = i; |
| xatp.space = XENMAPSPACE_grant_table; |
| xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i; |
| rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp); |
| if (rc != 0) { |
| printk(KERN_WARNING |
| "grant table add_to_physmap failed, err=%d\n", rc); |
| break; |
| } |
| } while (i-- > start_idx); |
| |
| return rc; |
| } |
| |
| /* No need for kzalloc as it is initialized in following hypercall |
| * GNTTABOP_setup_table. |
| */ |
| frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC); |
| if (!frames) |
| return -ENOMEM; |
| |
| setup.dom = DOMID_SELF; |
| setup.nr_frames = nr_gframes; |
| set_xen_guest_handle(setup.frame_list, frames); |
| |
| rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1); |
| if (rc == -ENOSYS) { |
| kfree(frames); |
| return -ENOSYS; |
| } |
| |
| BUG_ON(rc || setup.status); |
| |
| rc = gnttab_interface->map_frames(frames, nr_gframes); |
| |
| kfree(frames); |
| |
| return rc; |
| } |
| |
| static struct gnttab_ops gnttab_v1_ops = { |
| .map_frames = gnttab_map_frames_v1, |
| .unmap_frames = gnttab_unmap_frames_v1, |
| .update_entry = gnttab_update_entry_v1, |
| .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1, |
| .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1, |
| .query_foreign_access = gnttab_query_foreign_access_v1, |
| }; |
| |
| static struct gnttab_ops gnttab_v2_ops = { |
| .map_frames = gnttab_map_frames_v2, |
| .unmap_frames = gnttab_unmap_frames_v2, |
| .update_entry = gnttab_update_entry_v2, |
| .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2, |
| .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2, |
| .query_foreign_access = gnttab_query_foreign_access_v2, |
| .update_subpage_entry = gnttab_update_subpage_entry_v2, |
| .update_trans_entry = gnttab_update_trans_entry_v2, |
| }; |
| |
| static void gnttab_request_version(void) |
| { |
| int rc; |
| struct gnttab_set_version gsv; |
| |
| if (xen_hvm_domain()) |
| gsv.version = 1; |
| else |
| gsv.version = 2; |
| rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1); |
| if (rc == 0 && gsv.version == 2) { |
| grant_table_version = 2; |
| gnttab_interface = &gnttab_v2_ops; |
| } else if (grant_table_version == 2) { |
| /* |
| * If we've already used version 2 features, |
| * but then suddenly discover that they're not |
| * available (e.g. migrating to an older |
| * version of Xen), almost unbounded badness |
| * can happen. |
| */ |
| panic("we need grant tables version 2, but only version 1 is available"); |
| } else { |
| grant_table_version = 1; |
| gnttab_interface = &gnttab_v1_ops; |
| } |
| printk(KERN_INFO "Grant tables using version %d layout.\n", |
| grant_table_version); |
| } |
| |
| int gnttab_resume(void) |
| { |
| unsigned int max_nr_gframes; |
| |
| gnttab_request_version(); |
| max_nr_gframes = gnttab_max_grant_frames(); |
| if (max_nr_gframes < nr_grant_frames) |
| return -ENOSYS; |
| |
| if (xen_pv_domain()) |
| return gnttab_map(0, nr_grant_frames - 1); |
| |
| if (gnttab_shared.addr == NULL) { |
| gnttab_shared.addr = ioremap(xen_hvm_resume_frames, |
| PAGE_SIZE * max_nr_gframes); |
| if (gnttab_shared.addr == NULL) { |
| printk(KERN_WARNING |
| "Failed to ioremap gnttab share frames!"); |
| return -ENOMEM; |
| } |
| } |
| |
| gnttab_map(0, nr_grant_frames - 1); |
| |
| return 0; |
| } |
| |
| int gnttab_suspend(void) |
| { |
| gnttab_interface->unmap_frames(); |
| return 0; |
| } |
| |
| static int gnttab_expand(unsigned int req_entries) |
| { |
| int rc; |
| unsigned int cur, extra; |
| |
| cur = nr_grant_frames; |
| extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) / |
| GREFS_PER_GRANT_FRAME); |
| if (cur + extra > gnttab_max_grant_frames()) |
| return -ENOSPC; |
| |
| rc = gnttab_map(cur, cur + extra - 1); |
| if (rc == 0) |
| rc = grow_gnttab_list(extra); |
| |
| return rc; |
| } |
| |
| int gnttab_init(void) |
| { |
| int i; |
| unsigned int max_nr_glist_frames, nr_glist_frames; |
| unsigned int nr_init_grefs; |
| int ret; |
| |
| nr_grant_frames = 1; |
| boot_max_nr_grant_frames = __max_nr_grant_frames(); |
| |
| /* Determine the maximum number of frames required for the |
| * grant reference free list on the current hypervisor. |
| */ |
| max_nr_glist_frames = (boot_max_nr_grant_frames * |
| GREFS_PER_GRANT_FRAME / RPP); |
| |
| gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *), |
| GFP_KERNEL); |
| if (gnttab_list == NULL) |
| return -ENOMEM; |
| |
| nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| for (i = 0; i < nr_glist_frames; i++) { |
| gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL); |
| if (gnttab_list[i] == NULL) { |
| ret = -ENOMEM; |
| goto ini_nomem; |
| } |
| } |
| |
| if (gnttab_resume() < 0) { |
| ret = -ENODEV; |
| goto ini_nomem; |
| } |
| |
| nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME; |
| |
| for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++) |
| gnttab_entry(i) = i + 1; |
| |
| gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END; |
| gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES; |
| gnttab_free_head = NR_RESERVED_ENTRIES; |
| |
| printk("Grant table initialized\n"); |
| return 0; |
| |
| ini_nomem: |
| for (i--; i >= 0; i--) |
| free_page((unsigned long)gnttab_list[i]); |
| kfree(gnttab_list); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(gnttab_init); |
| |
| static int __devinit __gnttab_init(void) |
| { |
| /* Delay grant-table initialization in the PV on HVM case */ |
| if (xen_hvm_domain()) |
| return 0; |
| |
| if (!xen_pv_domain()) |
| return -ENODEV; |
| |
| return gnttab_init(); |
| } |
| |
| core_initcall(__gnttab_init); |