| /* |
| * Xen mmu operations |
| * |
| * This file contains the various mmu fetch and update operations. |
| * The most important job they must perform is the mapping between the |
| * domain's pfn and the overall machine mfns. |
| * |
| * Xen allows guests to directly update the pagetable, in a controlled |
| * fashion. In other words, the guest modifies the same pagetable |
| * that the CPU actually uses, which eliminates the overhead of having |
| * a separate shadow pagetable. |
| * |
| * In order to allow this, it falls on the guest domain to map its |
| * notion of a "physical" pfn - which is just a domain-local linear |
| * address - into a real "machine address" which the CPU's MMU can |
| * use. |
| * |
| * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be |
| * inserted directly into the pagetable. When creating a new |
| * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely, |
| * when reading the content back with __(pgd|pmd|pte)_val, it converts |
| * the mfn back into a pfn. |
| * |
| * The other constraint is that all pages which make up a pagetable |
| * must be mapped read-only in the guest. This prevents uncontrolled |
| * guest updates to the pagetable. Xen strictly enforces this, and |
| * will disallow any pagetable update which will end up mapping a |
| * pagetable page RW, and will disallow using any writable page as a |
| * pagetable. |
| * |
| * Naively, when loading %cr3 with the base of a new pagetable, Xen |
| * would need to validate the whole pagetable before going on. |
| * Naturally, this is quite slow. The solution is to "pin" a |
| * pagetable, which enforces all the constraints on the pagetable even |
| * when it is not actively in use. This menas that Xen can be assured |
| * that it is still valid when you do load it into %cr3, and doesn't |
| * need to revalidate it. |
| * |
| * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 |
| */ |
| #include <linux/sched.h> |
| #include <linux/highmem.h> |
| #include <linux/debugfs.h> |
| #include <linux/bug.h> |
| #include <linux/vmalloc.h> |
| #include <linux/module.h> |
| #include <linux/gfp.h> |
| #include <linux/memblock.h> |
| #include <linux/seq_file.h> |
| |
| #include <trace/events/xen.h> |
| |
| #include <asm/pgtable.h> |
| #include <asm/tlbflush.h> |
| #include <asm/fixmap.h> |
| #include <asm/mmu_context.h> |
| #include <asm/setup.h> |
| #include <asm/paravirt.h> |
| #include <asm/e820.h> |
| #include <asm/linkage.h> |
| #include <asm/page.h> |
| #include <asm/init.h> |
| #include <asm/pat.h> |
| #include <asm/smp.h> |
| |
| #include <asm/xen/hypercall.h> |
| #include <asm/xen/hypervisor.h> |
| |
| #include <xen/xen.h> |
| #include <xen/page.h> |
| #include <xen/interface/xen.h> |
| #include <xen/interface/hvm/hvm_op.h> |
| #include <xen/interface/version.h> |
| #include <xen/interface/memory.h> |
| #include <xen/hvc-console.h> |
| |
| #include "multicalls.h" |
| #include "mmu.h" |
| #include "debugfs.h" |
| |
| /* |
| * Protects atomic reservation decrease/increase against concurrent increases. |
| * Also protects non-atomic updates of current_pages and balloon lists. |
| */ |
| DEFINE_SPINLOCK(xen_reservation_lock); |
| |
| #ifdef CONFIG_X86_32 |
| /* |
| * Identity map, in addition to plain kernel map. This needs to be |
| * large enough to allocate page table pages to allocate the rest. |
| * Each page can map 2MB. |
| */ |
| #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4) |
| static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES); |
| #endif |
| #ifdef CONFIG_X86_64 |
| /* l3 pud for userspace vsyscall mapping */ |
| static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss; |
| #endif /* CONFIG_X86_64 */ |
| |
| /* |
| * Note about cr3 (pagetable base) values: |
| * |
| * xen_cr3 contains the current logical cr3 value; it contains the |
| * last set cr3. This may not be the current effective cr3, because |
| * its update may be being lazily deferred. However, a vcpu looking |
| * at its own cr3 can use this value knowing that it everything will |
| * be self-consistent. |
| * |
| * xen_current_cr3 contains the actual vcpu cr3; it is set once the |
| * hypercall to set the vcpu cr3 is complete (so it may be a little |
| * out of date, but it will never be set early). If one vcpu is |
| * looking at another vcpu's cr3 value, it should use this variable. |
| */ |
| DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */ |
| DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */ |
| |
| |
| /* |
| * Just beyond the highest usermode address. STACK_TOP_MAX has a |
| * redzone above it, so round it up to a PGD boundary. |
| */ |
| #define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK) |
| |
| unsigned long arbitrary_virt_to_mfn(void *vaddr) |
| { |
| xmaddr_t maddr = arbitrary_virt_to_machine(vaddr); |
| |
| return PFN_DOWN(maddr.maddr); |
| } |
| |
| xmaddr_t arbitrary_virt_to_machine(void *vaddr) |
| { |
| unsigned long address = (unsigned long)vaddr; |
| unsigned int level; |
| pte_t *pte; |
| unsigned offset; |
| |
| /* |
| * if the PFN is in the linear mapped vaddr range, we can just use |
| * the (quick) virt_to_machine() p2m lookup |
| */ |
| if (virt_addr_valid(vaddr)) |
| return virt_to_machine(vaddr); |
| |
| /* otherwise we have to do a (slower) full page-table walk */ |
| |
| pte = lookup_address(address, &level); |
| BUG_ON(pte == NULL); |
| offset = address & ~PAGE_MASK; |
| return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset); |
| } |
| EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine); |
| |
| void make_lowmem_page_readonly(void *vaddr) |
| { |
| pte_t *pte, ptev; |
| unsigned long address = (unsigned long)vaddr; |
| unsigned int level; |
| |
| pte = lookup_address(address, &level); |
| if (pte == NULL) |
| return; /* vaddr missing */ |
| |
| ptev = pte_wrprotect(*pte); |
| |
| if (HYPERVISOR_update_va_mapping(address, ptev, 0)) |
| BUG(); |
| } |
| |
| void make_lowmem_page_readwrite(void *vaddr) |
| { |
| pte_t *pte, ptev; |
| unsigned long address = (unsigned long)vaddr; |
| unsigned int level; |
| |
| pte = lookup_address(address, &level); |
| if (pte == NULL) |
| return; /* vaddr missing */ |
| |
| ptev = pte_mkwrite(*pte); |
| |
| if (HYPERVISOR_update_va_mapping(address, ptev, 0)) |
| BUG(); |
| } |
| |
| |
| static bool xen_page_pinned(void *ptr) |
| { |
| struct page *page = virt_to_page(ptr); |
| |
| return PagePinned(page); |
| } |
| |
| void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid) |
| { |
| struct multicall_space mcs; |
| struct mmu_update *u; |
| |
| trace_xen_mmu_set_domain_pte(ptep, pteval, domid); |
| |
| mcs = xen_mc_entry(sizeof(*u)); |
| u = mcs.args; |
| |
| /* ptep might be kmapped when using 32-bit HIGHPTE */ |
| u->ptr = virt_to_machine(ptep).maddr; |
| u->val = pte_val_ma(pteval); |
| |
| MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } |
| EXPORT_SYMBOL_GPL(xen_set_domain_pte); |
| |
| static void xen_extend_mmu_update(const struct mmu_update *update) |
| { |
| struct multicall_space mcs; |
| struct mmu_update *u; |
| |
| mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u)); |
| |
| if (mcs.mc != NULL) { |
| mcs.mc->args[1]++; |
| } else { |
| mcs = __xen_mc_entry(sizeof(*u)); |
| MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); |
| } |
| |
| u = mcs.args; |
| *u = *update; |
| } |
| |
| static void xen_extend_mmuext_op(const struct mmuext_op *op) |
| { |
| struct multicall_space mcs; |
| struct mmuext_op *u; |
| |
| mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u)); |
| |
| if (mcs.mc != NULL) { |
| mcs.mc->args[1]++; |
| } else { |
| mcs = __xen_mc_entry(sizeof(*u)); |
| MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); |
| } |
| |
| u = mcs.args; |
| *u = *op; |
| } |
| |
| static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val) |
| { |
| struct mmu_update u; |
| |
| preempt_disable(); |
| |
| xen_mc_batch(); |
| |
| /* ptr may be ioremapped for 64-bit pagetable setup */ |
| u.ptr = arbitrary_virt_to_machine(ptr).maddr; |
| u.val = pmd_val_ma(val); |
| xen_extend_mmu_update(&u); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| preempt_enable(); |
| } |
| |
| static void xen_set_pmd(pmd_t *ptr, pmd_t val) |
| { |
| trace_xen_mmu_set_pmd(ptr, val); |
| |
| /* If page is not pinned, we can just update the entry |
| directly */ |
| if (!xen_page_pinned(ptr)) { |
| *ptr = val; |
| return; |
| } |
| |
| xen_set_pmd_hyper(ptr, val); |
| } |
| |
| /* |
| * Associate a virtual page frame with a given physical page frame |
| * and protection flags for that frame. |
| */ |
| void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) |
| { |
| set_pte_vaddr(vaddr, mfn_pte(mfn, flags)); |
| } |
| |
| static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval) |
| { |
| struct mmu_update u; |
| |
| if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU) |
| return false; |
| |
| xen_mc_batch(); |
| |
| u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE; |
| u.val = pte_val_ma(pteval); |
| xen_extend_mmu_update(&u); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| return true; |
| } |
| |
| static inline void __xen_set_pte(pte_t *ptep, pte_t pteval) |
| { |
| if (!xen_batched_set_pte(ptep, pteval)) |
| native_set_pte(ptep, pteval); |
| } |
| |
| static void xen_set_pte(pte_t *ptep, pte_t pteval) |
| { |
| trace_xen_mmu_set_pte(ptep, pteval); |
| __xen_set_pte(ptep, pteval); |
| } |
| |
| static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, |
| pte_t *ptep, pte_t pteval) |
| { |
| trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval); |
| __xen_set_pte(ptep, pteval); |
| } |
| |
| pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, |
| unsigned long addr, pte_t *ptep) |
| { |
| /* Just return the pte as-is. We preserve the bits on commit */ |
| trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep); |
| return *ptep; |
| } |
| |
| void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr, |
| pte_t *ptep, pte_t pte) |
| { |
| struct mmu_update u; |
| |
| trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte); |
| xen_mc_batch(); |
| |
| u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD; |
| u.val = pte_val_ma(pte); |
| xen_extend_mmu_update(&u); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } |
| |
| /* Assume pteval_t is equivalent to all the other *val_t types. */ |
| static pteval_t pte_mfn_to_pfn(pteval_t val) |
| { |
| if (val & _PAGE_PRESENT) { |
| unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; |
| unsigned long pfn = mfn_to_pfn(mfn); |
| |
| pteval_t flags = val & PTE_FLAGS_MASK; |
| if (unlikely(pfn == ~0)) |
| val = flags & ~_PAGE_PRESENT; |
| else |
| val = ((pteval_t)pfn << PAGE_SHIFT) | flags; |
| } |
| |
| return val; |
| } |
| |
| static pteval_t pte_pfn_to_mfn(pteval_t val) |
| { |
| if (val & _PAGE_PRESENT) { |
| unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; |
| pteval_t flags = val & PTE_FLAGS_MASK; |
| unsigned long mfn; |
| |
| if (!xen_feature(XENFEAT_auto_translated_physmap)) |
| mfn = get_phys_to_machine(pfn); |
| else |
| mfn = pfn; |
| /* |
| * If there's no mfn for the pfn, then just create an |
| * empty non-present pte. Unfortunately this loses |
| * information about the original pfn, so |
| * pte_mfn_to_pfn is asymmetric. |
| */ |
| if (unlikely(mfn == INVALID_P2M_ENTRY)) { |
| mfn = 0; |
| flags = 0; |
| } else { |
| /* |
| * Paramount to do this test _after_ the |
| * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY & |
| * IDENTITY_FRAME_BIT resolves to true. |
| */ |
| mfn &= ~FOREIGN_FRAME_BIT; |
| if (mfn & IDENTITY_FRAME_BIT) { |
| mfn &= ~IDENTITY_FRAME_BIT; |
| flags |= _PAGE_IOMAP; |
| } |
| } |
| val = ((pteval_t)mfn << PAGE_SHIFT) | flags; |
| } |
| |
| return val; |
| } |
| |
| static pteval_t iomap_pte(pteval_t val) |
| { |
| if (val & _PAGE_PRESENT) { |
| unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; |
| pteval_t flags = val & PTE_FLAGS_MASK; |
| |
| /* We assume the pte frame number is a MFN, so |
| just use it as-is. */ |
| val = ((pteval_t)pfn << PAGE_SHIFT) | flags; |
| } |
| |
| return val; |
| } |
| |
| static pteval_t xen_pte_val(pte_t pte) |
| { |
| pteval_t pteval = pte.pte; |
| #if 0 |
| /* If this is a WC pte, convert back from Xen WC to Linux WC */ |
| if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) { |
| WARN_ON(!pat_enabled); |
| pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT; |
| } |
| #endif |
| if (xen_initial_domain() && (pteval & _PAGE_IOMAP)) |
| return pteval; |
| |
| return pte_mfn_to_pfn(pteval); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val); |
| |
| static pgdval_t xen_pgd_val(pgd_t pgd) |
| { |
| return pte_mfn_to_pfn(pgd.pgd); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); |
| |
| /* |
| * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7 |
| * are reserved for now, to correspond to the Intel-reserved PAT |
| * types. |
| * |
| * We expect Linux's PAT set as follows: |
| * |
| * Idx PTE flags Linux Xen Default |
| * 0 WB WB WB |
| * 1 PWT WC WT WT |
| * 2 PCD UC- UC- UC- |
| * 3 PCD PWT UC UC UC |
| * 4 PAT WB WC WB |
| * 5 PAT PWT WC WP WT |
| * 6 PAT PCD UC- UC UC- |
| * 7 PAT PCD PWT UC UC UC |
| */ |
| |
| void xen_set_pat(u64 pat) |
| { |
| /* We expect Linux to use a PAT setting of |
| * UC UC- WC WB (ignoring the PAT flag) */ |
| WARN_ON(pat != 0x0007010600070106ull); |
| } |
| |
| static pte_t xen_make_pte(pteval_t pte) |
| { |
| phys_addr_t addr = (pte & PTE_PFN_MASK); |
| #if 0 |
| /* If Linux is trying to set a WC pte, then map to the Xen WC. |
| * If _PAGE_PAT is set, then it probably means it is really |
| * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope |
| * things work out OK... |
| * |
| * (We should never see kernel mappings with _PAGE_PSE set, |
| * but we could see hugetlbfs mappings, I think.). |
| */ |
| if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) { |
| if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT) |
| pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT; |
| } |
| #endif |
| /* |
| * Unprivileged domains are allowed to do IOMAPpings for |
| * PCI passthrough, but not map ISA space. The ISA |
| * mappings are just dummy local mappings to keep other |
| * parts of the kernel happy. |
| */ |
| if (unlikely(pte & _PAGE_IOMAP) && |
| (xen_initial_domain() || addr >= ISA_END_ADDRESS)) { |
| pte = iomap_pte(pte); |
| } else { |
| pte &= ~_PAGE_IOMAP; |
| pte = pte_pfn_to_mfn(pte); |
| } |
| |
| return native_make_pte(pte); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte); |
| |
| static pgd_t xen_make_pgd(pgdval_t pgd) |
| { |
| pgd = pte_pfn_to_mfn(pgd); |
| return native_make_pgd(pgd); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd); |
| |
| static pmdval_t xen_pmd_val(pmd_t pmd) |
| { |
| return pte_mfn_to_pfn(pmd.pmd); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val); |
| |
| static void xen_set_pud_hyper(pud_t *ptr, pud_t val) |
| { |
| struct mmu_update u; |
| |
| preempt_disable(); |
| |
| xen_mc_batch(); |
| |
| /* ptr may be ioremapped for 64-bit pagetable setup */ |
| u.ptr = arbitrary_virt_to_machine(ptr).maddr; |
| u.val = pud_val_ma(val); |
| xen_extend_mmu_update(&u); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| preempt_enable(); |
| } |
| |
| static void xen_set_pud(pud_t *ptr, pud_t val) |
| { |
| trace_xen_mmu_set_pud(ptr, val); |
| |
| /* If page is not pinned, we can just update the entry |
| directly */ |
| if (!xen_page_pinned(ptr)) { |
| *ptr = val; |
| return; |
| } |
| |
| xen_set_pud_hyper(ptr, val); |
| } |
| |
| #ifdef CONFIG_X86_PAE |
| static void xen_set_pte_atomic(pte_t *ptep, pte_t pte) |
| { |
| trace_xen_mmu_set_pte_atomic(ptep, pte); |
| set_64bit((u64 *)ptep, native_pte_val(pte)); |
| } |
| |
| static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) |
| { |
| trace_xen_mmu_pte_clear(mm, addr, ptep); |
| if (!xen_batched_set_pte(ptep, native_make_pte(0))) |
| native_pte_clear(mm, addr, ptep); |
| } |
| |
| static void xen_pmd_clear(pmd_t *pmdp) |
| { |
| trace_xen_mmu_pmd_clear(pmdp); |
| set_pmd(pmdp, __pmd(0)); |
| } |
| #endif /* CONFIG_X86_PAE */ |
| |
| static pmd_t xen_make_pmd(pmdval_t pmd) |
| { |
| pmd = pte_pfn_to_mfn(pmd); |
| return native_make_pmd(pmd); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd); |
| |
| #if PAGETABLE_LEVELS == 4 |
| static pudval_t xen_pud_val(pud_t pud) |
| { |
| return pte_mfn_to_pfn(pud.pud); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val); |
| |
| static pud_t xen_make_pud(pudval_t pud) |
| { |
| pud = pte_pfn_to_mfn(pud); |
| |
| return native_make_pud(pud); |
| } |
| PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud); |
| |
| static pgd_t *xen_get_user_pgd(pgd_t *pgd) |
| { |
| pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK); |
| unsigned offset = pgd - pgd_page; |
| pgd_t *user_ptr = NULL; |
| |
| if (offset < pgd_index(USER_LIMIT)) { |
| struct page *page = virt_to_page(pgd_page); |
| user_ptr = (pgd_t *)page->private; |
| if (user_ptr) |
| user_ptr += offset; |
| } |
| |
| return user_ptr; |
| } |
| |
| static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val) |
| { |
| struct mmu_update u; |
| |
| u.ptr = virt_to_machine(ptr).maddr; |
| u.val = pgd_val_ma(val); |
| xen_extend_mmu_update(&u); |
| } |
| |
| /* |
| * Raw hypercall-based set_pgd, intended for in early boot before |
| * there's a page structure. This implies: |
| * 1. The only existing pagetable is the kernel's |
| * 2. It is always pinned |
| * 3. It has no user pagetable attached to it |
| */ |
| static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val) |
| { |
| preempt_disable(); |
| |
| xen_mc_batch(); |
| |
| __xen_set_pgd_hyper(ptr, val); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| preempt_enable(); |
| } |
| |
| static void xen_set_pgd(pgd_t *ptr, pgd_t val) |
| { |
| pgd_t *user_ptr = xen_get_user_pgd(ptr); |
| |
| trace_xen_mmu_set_pgd(ptr, user_ptr, val); |
| |
| /* If page is not pinned, we can just update the entry |
| directly */ |
| if (!xen_page_pinned(ptr)) { |
| *ptr = val; |
| if (user_ptr) { |
| WARN_ON(xen_page_pinned(user_ptr)); |
| *user_ptr = val; |
| } |
| return; |
| } |
| |
| /* If it's pinned, then we can at least batch the kernel and |
| user updates together. */ |
| xen_mc_batch(); |
| |
| __xen_set_pgd_hyper(ptr, val); |
| if (user_ptr) |
| __xen_set_pgd_hyper(user_ptr, val); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } |
| #endif /* PAGETABLE_LEVELS == 4 */ |
| |
| /* |
| * (Yet another) pagetable walker. This one is intended for pinning a |
| * pagetable. This means that it walks a pagetable and calls the |
| * callback function on each page it finds making up the page table, |
| * at every level. It walks the entire pagetable, but it only bothers |
| * pinning pte pages which are below limit. In the normal case this |
| * will be STACK_TOP_MAX, but at boot we need to pin up to |
| * FIXADDR_TOP. |
| * |
| * For 32-bit the important bit is that we don't pin beyond there, |
| * because then we start getting into Xen's ptes. |
| * |
| * For 64-bit, we must skip the Xen hole in the middle of the address |
| * space, just after the big x86-64 virtual hole. |
| */ |
| static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd, |
| int (*func)(struct mm_struct *mm, struct page *, |
| enum pt_level), |
| unsigned long limit) |
| { |
| int flush = 0; |
| unsigned hole_low, hole_high; |
| unsigned pgdidx_limit, pudidx_limit, pmdidx_limit; |
| unsigned pgdidx, pudidx, pmdidx; |
| |
| /* The limit is the last byte to be touched */ |
| limit--; |
| BUG_ON(limit >= FIXADDR_TOP); |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return 0; |
| |
| /* |
| * 64-bit has a great big hole in the middle of the address |
| * space, which contains the Xen mappings. On 32-bit these |
| * will end up making a zero-sized hole and so is a no-op. |
| */ |
| hole_low = pgd_index(USER_LIMIT); |
| hole_high = pgd_index(PAGE_OFFSET); |
| |
| pgdidx_limit = pgd_index(limit); |
| #if PTRS_PER_PUD > 1 |
| pudidx_limit = pud_index(limit); |
| #else |
| pudidx_limit = 0; |
| #endif |
| #if PTRS_PER_PMD > 1 |
| pmdidx_limit = pmd_index(limit); |
| #else |
| pmdidx_limit = 0; |
| #endif |
| |
| for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) { |
| pud_t *pud; |
| |
| if (pgdidx >= hole_low && pgdidx < hole_high) |
| continue; |
| |
| if (!pgd_val(pgd[pgdidx])) |
| continue; |
| |
| pud = pud_offset(&pgd[pgdidx], 0); |
| |
| if (PTRS_PER_PUD > 1) /* not folded */ |
| flush |= (*func)(mm, virt_to_page(pud), PT_PUD); |
| |
| for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) { |
| pmd_t *pmd; |
| |
| if (pgdidx == pgdidx_limit && |
| pudidx > pudidx_limit) |
| goto out; |
| |
| if (pud_none(pud[pudidx])) |
| continue; |
| |
| pmd = pmd_offset(&pud[pudidx], 0); |
| |
| if (PTRS_PER_PMD > 1) /* not folded */ |
| flush |= (*func)(mm, virt_to_page(pmd), PT_PMD); |
| |
| for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) { |
| struct page *pte; |
| |
| if (pgdidx == pgdidx_limit && |
| pudidx == pudidx_limit && |
| pmdidx > pmdidx_limit) |
| goto out; |
| |
| if (pmd_none(pmd[pmdidx])) |
| continue; |
| |
| pte = pmd_page(pmd[pmdidx]); |
| flush |= (*func)(mm, pte, PT_PTE); |
| } |
| } |
| } |
| |
| out: |
| /* Do the top level last, so that the callbacks can use it as |
| a cue to do final things like tlb flushes. */ |
| flush |= (*func)(mm, virt_to_page(pgd), PT_PGD); |
| |
| return flush; |
| } |
| |
| static int xen_pgd_walk(struct mm_struct *mm, |
| int (*func)(struct mm_struct *mm, struct page *, |
| enum pt_level), |
| unsigned long limit) |
| { |
| return __xen_pgd_walk(mm, mm->pgd, func, limit); |
| } |
| |
| /* If we're using split pte locks, then take the page's lock and |
| return a pointer to it. Otherwise return NULL. */ |
| static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm) |
| { |
| spinlock_t *ptl = NULL; |
| |
| #if USE_SPLIT_PTLOCKS |
| ptl = __pte_lockptr(page); |
| spin_lock_nest_lock(ptl, &mm->page_table_lock); |
| #endif |
| |
| return ptl; |
| } |
| |
| static void xen_pte_unlock(void *v) |
| { |
| spinlock_t *ptl = v; |
| spin_unlock(ptl); |
| } |
| |
| static void xen_do_pin(unsigned level, unsigned long pfn) |
| { |
| struct mmuext_op op; |
| |
| op.cmd = level; |
| op.arg1.mfn = pfn_to_mfn(pfn); |
| |
| xen_extend_mmuext_op(&op); |
| } |
| |
| static int xen_pin_page(struct mm_struct *mm, struct page *page, |
| enum pt_level level) |
| { |
| unsigned pgfl = TestSetPagePinned(page); |
| int flush; |
| |
| if (pgfl) |
| flush = 0; /* already pinned */ |
| else if (PageHighMem(page)) |
| /* kmaps need flushing if we found an unpinned |
| highpage */ |
| flush = 1; |
| else { |
| void *pt = lowmem_page_address(page); |
| unsigned long pfn = page_to_pfn(page); |
| struct multicall_space mcs = __xen_mc_entry(0); |
| spinlock_t *ptl; |
| |
| flush = 0; |
| |
| /* |
| * We need to hold the pagetable lock between the time |
| * we make the pagetable RO and when we actually pin |
| * it. If we don't, then other users may come in and |
| * attempt to update the pagetable by writing it, |
| * which will fail because the memory is RO but not |
| * pinned, so Xen won't do the trap'n'emulate. |
| * |
| * If we're using split pte locks, we can't hold the |
| * entire pagetable's worth of locks during the |
| * traverse, because we may wrap the preempt count (8 |
| * bits). The solution is to mark RO and pin each PTE |
| * page while holding the lock. This means the number |
| * of locks we end up holding is never more than a |
| * batch size (~32 entries, at present). |
| * |
| * If we're not using split pte locks, we needn't pin |
| * the PTE pages independently, because we're |
| * protected by the overall pagetable lock. |
| */ |
| ptl = NULL; |
| if (level == PT_PTE) |
| ptl = xen_pte_lock(page, mm); |
| |
| MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, |
| pfn_pte(pfn, PAGE_KERNEL_RO), |
| level == PT_PGD ? UVMF_TLB_FLUSH : 0); |
| |
| if (ptl) { |
| xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn); |
| |
| /* Queue a deferred unlock for when this batch |
| is completed. */ |
| xen_mc_callback(xen_pte_unlock, ptl); |
| } |
| } |
| |
| return flush; |
| } |
| |
| /* This is called just after a mm has been created, but it has not |
| been used yet. We need to make sure that its pagetable is all |
| read-only, and can be pinned. */ |
| static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd) |
| { |
| trace_xen_mmu_pgd_pin(mm, pgd); |
| |
| xen_mc_batch(); |
| |
| if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) { |
| /* re-enable interrupts for flushing */ |
| xen_mc_issue(0); |
| |
| kmap_flush_unused(); |
| |
| xen_mc_batch(); |
| } |
| |
| #ifdef CONFIG_X86_64 |
| { |
| pgd_t *user_pgd = xen_get_user_pgd(pgd); |
| |
| xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd))); |
| |
| if (user_pgd) { |
| xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD); |
| xen_do_pin(MMUEXT_PIN_L4_TABLE, |
| PFN_DOWN(__pa(user_pgd))); |
| } |
| } |
| #else /* CONFIG_X86_32 */ |
| #ifdef CONFIG_X86_PAE |
| /* Need to make sure unshared kernel PMD is pinnable */ |
| xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]), |
| PT_PMD); |
| #endif |
| xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd))); |
| #endif /* CONFIG_X86_64 */ |
| xen_mc_issue(0); |
| } |
| |
| static void xen_pgd_pin(struct mm_struct *mm) |
| { |
| __xen_pgd_pin(mm, mm->pgd); |
| } |
| |
| /* |
| * On save, we need to pin all pagetables to make sure they get their |
| * mfns turned into pfns. Search the list for any unpinned pgds and pin |
| * them (unpinned pgds are not currently in use, probably because the |
| * process is under construction or destruction). |
| * |
| * Expected to be called in stop_machine() ("equivalent to taking |
| * every spinlock in the system"), so the locking doesn't really |
| * matter all that much. |
| */ |
| void xen_mm_pin_all(void) |
| { |
| struct page *page; |
| |
| spin_lock(&pgd_lock); |
| |
| list_for_each_entry(page, &pgd_list, lru) { |
| if (!PagePinned(page)) { |
| __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page)); |
| SetPageSavePinned(page); |
| } |
| } |
| |
| spin_unlock(&pgd_lock); |
| } |
| |
| /* |
| * The init_mm pagetable is really pinned as soon as its created, but |
| * that's before we have page structures to store the bits. So do all |
| * the book-keeping now. |
| */ |
| static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page, |
| enum pt_level level) |
| { |
| SetPagePinned(page); |
| return 0; |
| } |
| |
| static void __init xen_mark_init_mm_pinned(void) |
| { |
| xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP); |
| } |
| |
| static int xen_unpin_page(struct mm_struct *mm, struct page *page, |
| enum pt_level level) |
| { |
| unsigned pgfl = TestClearPagePinned(page); |
| |
| if (pgfl && !PageHighMem(page)) { |
| void *pt = lowmem_page_address(page); |
| unsigned long pfn = page_to_pfn(page); |
| spinlock_t *ptl = NULL; |
| struct multicall_space mcs; |
| |
| /* |
| * Do the converse to pin_page. If we're using split |
| * pte locks, we must be holding the lock for while |
| * the pte page is unpinned but still RO to prevent |
| * concurrent updates from seeing it in this |
| * partially-pinned state. |
| */ |
| if (level == PT_PTE) { |
| ptl = xen_pte_lock(page, mm); |
| |
| if (ptl) |
| xen_do_pin(MMUEXT_UNPIN_TABLE, pfn); |
| } |
| |
| mcs = __xen_mc_entry(0); |
| |
| MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, |
| pfn_pte(pfn, PAGE_KERNEL), |
| level == PT_PGD ? UVMF_TLB_FLUSH : 0); |
| |
| if (ptl) { |
| /* unlock when batch completed */ |
| xen_mc_callback(xen_pte_unlock, ptl); |
| } |
| } |
| |
| return 0; /* never need to flush on unpin */ |
| } |
| |
| /* Release a pagetables pages back as normal RW */ |
| static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd) |
| { |
| trace_xen_mmu_pgd_unpin(mm, pgd); |
| |
| xen_mc_batch(); |
| |
| xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); |
| |
| #ifdef CONFIG_X86_64 |
| { |
| pgd_t *user_pgd = xen_get_user_pgd(pgd); |
| |
| if (user_pgd) { |
| xen_do_pin(MMUEXT_UNPIN_TABLE, |
| PFN_DOWN(__pa(user_pgd))); |
| xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD); |
| } |
| } |
| #endif |
| |
| #ifdef CONFIG_X86_PAE |
| /* Need to make sure unshared kernel PMD is unpinned */ |
| xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]), |
| PT_PMD); |
| #endif |
| |
| __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT); |
| |
| xen_mc_issue(0); |
| } |
| |
| static void xen_pgd_unpin(struct mm_struct *mm) |
| { |
| __xen_pgd_unpin(mm, mm->pgd); |
| } |
| |
| /* |
| * On resume, undo any pinning done at save, so that the rest of the |
| * kernel doesn't see any unexpected pinned pagetables. |
| */ |
| void xen_mm_unpin_all(void) |
| { |
| struct page *page; |
| |
| spin_lock(&pgd_lock); |
| |
| list_for_each_entry(page, &pgd_list, lru) { |
| if (PageSavePinned(page)) { |
| BUG_ON(!PagePinned(page)); |
| __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page)); |
| ClearPageSavePinned(page); |
| } |
| } |
| |
| spin_unlock(&pgd_lock); |
| } |
| |
| static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) |
| { |
| spin_lock(&next->page_table_lock); |
| xen_pgd_pin(next); |
| spin_unlock(&next->page_table_lock); |
| } |
| |
| static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) |
| { |
| spin_lock(&mm->page_table_lock); |
| xen_pgd_pin(mm); |
| spin_unlock(&mm->page_table_lock); |
| } |
| |
| |
| #ifdef CONFIG_SMP |
| /* Another cpu may still have their %cr3 pointing at the pagetable, so |
| we need to repoint it somewhere else before we can unpin it. */ |
| static void drop_other_mm_ref(void *info) |
| { |
| struct mm_struct *mm = info; |
| struct mm_struct *active_mm; |
| |
| active_mm = this_cpu_read(cpu_tlbstate.active_mm); |
| |
| if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK) |
| leave_mm(smp_processor_id()); |
| |
| /* If this cpu still has a stale cr3 reference, then make sure |
| it has been flushed. */ |
| if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd)) |
| load_cr3(swapper_pg_dir); |
| } |
| |
| static void xen_drop_mm_ref(struct mm_struct *mm) |
| { |
| cpumask_var_t mask; |
| unsigned cpu; |
| |
| if (current->active_mm == mm) { |
| if (current->mm == mm) |
| load_cr3(swapper_pg_dir); |
| else |
| leave_mm(smp_processor_id()); |
| } |
| |
| /* Get the "official" set of cpus referring to our pagetable. */ |
| if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) { |
| for_each_online_cpu(cpu) { |
| if (!cpumask_test_cpu(cpu, mm_cpumask(mm)) |
| && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd)) |
| continue; |
| smp_call_function_single(cpu, drop_other_mm_ref, mm, 1); |
| } |
| return; |
| } |
| cpumask_copy(mask, mm_cpumask(mm)); |
| |
| /* It's possible that a vcpu may have a stale reference to our |
| cr3, because its in lazy mode, and it hasn't yet flushed |
| its set of pending hypercalls yet. In this case, we can |
| look at its actual current cr3 value, and force it to flush |
| if needed. */ |
| for_each_online_cpu(cpu) { |
| if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd)) |
| cpumask_set_cpu(cpu, mask); |
| } |
| |
| if (!cpumask_empty(mask)) |
| smp_call_function_many(mask, drop_other_mm_ref, mm, 1); |
| free_cpumask_var(mask); |
| } |
| #else |
| static void xen_drop_mm_ref(struct mm_struct *mm) |
| { |
| if (current->active_mm == mm) |
| load_cr3(swapper_pg_dir); |
| } |
| #endif |
| |
| /* |
| * While a process runs, Xen pins its pagetables, which means that the |
| * hypervisor forces it to be read-only, and it controls all updates |
| * to it. This means that all pagetable updates have to go via the |
| * hypervisor, which is moderately expensive. |
| * |
| * Since we're pulling the pagetable down, we switch to use init_mm, |
| * unpin old process pagetable and mark it all read-write, which |
| * allows further operations on it to be simple memory accesses. |
| * |
| * The only subtle point is that another CPU may be still using the |
| * pagetable because of lazy tlb flushing. This means we need need to |
| * switch all CPUs off this pagetable before we can unpin it. |
| */ |
| static void xen_exit_mmap(struct mm_struct *mm) |
| { |
| get_cpu(); /* make sure we don't move around */ |
| xen_drop_mm_ref(mm); |
| put_cpu(); |
| |
| spin_lock(&mm->page_table_lock); |
| |
| /* pgd may not be pinned in the error exit path of execve */ |
| if (xen_page_pinned(mm->pgd)) |
| xen_pgd_unpin(mm); |
| |
| spin_unlock(&mm->page_table_lock); |
| } |
| |
| static void __init xen_pagetable_setup_start(pgd_t *base) |
| { |
| } |
| |
| static __init void xen_mapping_pagetable_reserve(u64 start, u64 end) |
| { |
| /* reserve the range used */ |
| native_pagetable_reserve(start, end); |
| |
| /* set as RW the rest */ |
| printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end, |
| PFN_PHYS(pgt_buf_top)); |
| while (end < PFN_PHYS(pgt_buf_top)) { |
| make_lowmem_page_readwrite(__va(end)); |
| end += PAGE_SIZE; |
| } |
| } |
| |
| static void xen_post_allocator_init(void); |
| |
| #ifdef CONFIG_X86_64 |
| static void __init xen_cleanhighmap(unsigned long vaddr, |
| unsigned long vaddr_end) |
| { |
| unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1; |
| pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr); |
| |
| /* NOTE: The loop is more greedy than the cleanup_highmap variant. |
| * We include the PMD passed in on _both_ boundaries. */ |
| for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE)); |
| pmd++, vaddr += PMD_SIZE) { |
| if (pmd_none(*pmd)) |
| continue; |
| if (vaddr < (unsigned long) _text || vaddr > kernel_end) |
| set_pmd(pmd, __pmd(0)); |
| } |
| /* In case we did something silly, we should crash in this function |
| * instead of somewhere later and be confusing. */ |
| xen_mc_flush(); |
| } |
| #endif |
| static void __init xen_pagetable_setup_done(pgd_t *base) |
| { |
| #ifdef CONFIG_X86_64 |
| unsigned long size; |
| unsigned long addr; |
| #endif |
| |
| xen_setup_shared_info(); |
| #ifdef CONFIG_X86_64 |
| if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
| unsigned long new_mfn_list; |
| |
| size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); |
| |
| /* On 32-bit, we get zero so this never gets executed. */ |
| new_mfn_list = xen_revector_p2m_tree(); |
| if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) { |
| /* using __ka address and sticking INVALID_P2M_ENTRY! */ |
| memset((void *)xen_start_info->mfn_list, 0xff, size); |
| |
| /* We should be in __ka space. */ |
| BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map); |
| addr = xen_start_info->mfn_list; |
| /* We roundup to the PMD, which means that if anybody at this stage is |
| * using the __ka address of xen_start_info or xen_start_info->shared_info |
| * they are in going to crash. Fortunatly we have already revectored |
| * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */ |
| size = roundup(size, PMD_SIZE); |
| xen_cleanhighmap(addr, addr + size); |
| |
| size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); |
| memblock_free(__pa(xen_start_info->mfn_list), size); |
| /* And revector! Bye bye old array */ |
| xen_start_info->mfn_list = new_mfn_list; |
| } else |
| goto skip; |
| } |
| /* At this stage, cleanup_highmap has already cleaned __ka space |
| * from _brk_limit way up to the max_pfn_mapped (which is the end of |
| * the ramdisk). We continue on, erasing PMD entries that point to page |
| * tables - do note that they are accessible at this stage via __va. |
| * For good measure we also round up to the PMD - which means that if |
| * anybody is using __ka address to the initial boot-stack - and try |
| * to use it - they are going to crash. The xen_start_info has been |
| * taken care of already in xen_setup_kernel_pagetable. */ |
| addr = xen_start_info->pt_base; |
| size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE); |
| |
| xen_cleanhighmap(addr, addr + size); |
| xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base)); |
| #ifdef DEBUG |
| /* This is superflous and is not neccessary, but you know what |
| * lets do it. The MODULES_VADDR -> MODULES_END should be clear of |
| * anything at this stage. */ |
| xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1); |
| #endif |
| skip: |
| #endif |
| xen_post_allocator_init(); |
| } |
| |
| static void xen_write_cr2(unsigned long cr2) |
| { |
| this_cpu_read(xen_vcpu)->arch.cr2 = cr2; |
| } |
| |
| static unsigned long xen_read_cr2(void) |
| { |
| return this_cpu_read(xen_vcpu)->arch.cr2; |
| } |
| |
| unsigned long xen_read_cr2_direct(void) |
| { |
| return this_cpu_read(xen_vcpu_info.arch.cr2); |
| } |
| |
| static void xen_flush_tlb(void) |
| { |
| struct mmuext_op *op; |
| struct multicall_space mcs; |
| |
| trace_xen_mmu_flush_tlb(0); |
| |
| preempt_disable(); |
| |
| mcs = xen_mc_entry(sizeof(*op)); |
| |
| op = mcs.args; |
| op->cmd = MMUEXT_TLB_FLUSH_LOCAL; |
| MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| preempt_enable(); |
| } |
| |
| static void xen_flush_tlb_single(unsigned long addr) |
| { |
| struct mmuext_op *op; |
| struct multicall_space mcs; |
| |
| trace_xen_mmu_flush_tlb_single(addr); |
| |
| preempt_disable(); |
| |
| mcs = xen_mc_entry(sizeof(*op)); |
| op = mcs.args; |
| op->cmd = MMUEXT_INVLPG_LOCAL; |
| op->arg1.linear_addr = addr & PAGE_MASK; |
| MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| |
| preempt_enable(); |
| } |
| |
| static void xen_flush_tlb_others(const struct cpumask *cpus, |
| struct mm_struct *mm, unsigned long va) |
| { |
| struct { |
| struct mmuext_op op; |
| #ifdef CONFIG_SMP |
| DECLARE_BITMAP(mask, num_processors); |
| #else |
| DECLARE_BITMAP(mask, NR_CPUS); |
| #endif |
| } *args; |
| struct multicall_space mcs; |
| |
| trace_xen_mmu_flush_tlb_others(cpus, mm, va); |
| |
| if (cpumask_empty(cpus)) |
| return; /* nothing to do */ |
| |
| mcs = xen_mc_entry(sizeof(*args)); |
| args = mcs.args; |
| args->op.arg2.vcpumask = to_cpumask(args->mask); |
| |
| /* Remove us, and any offline CPUS. */ |
| cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask); |
| cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask)); |
| |
| if (va == TLB_FLUSH_ALL) { |
| args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; |
| } else { |
| args->op.cmd = MMUEXT_INVLPG_MULTI; |
| args->op.arg1.linear_addr = va; |
| } |
| |
| MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } |
| |
| static unsigned long xen_read_cr3(void) |
| { |
| return this_cpu_read(xen_cr3); |
| } |
| |
| static void set_current_cr3(void *v) |
| { |
| this_cpu_write(xen_current_cr3, (unsigned long)v); |
| } |
| |
| static void __xen_write_cr3(bool kernel, unsigned long cr3) |
| { |
| struct mmuext_op op; |
| unsigned long mfn; |
| |
| trace_xen_mmu_write_cr3(kernel, cr3); |
| |
| if (cr3) |
| mfn = pfn_to_mfn(PFN_DOWN(cr3)); |
| else |
| mfn = 0; |
| |
| WARN_ON(mfn == 0 && kernel); |
| |
| op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR; |
| op.arg1.mfn = mfn; |
| |
| xen_extend_mmuext_op(&op); |
| |
| if (kernel) { |
| this_cpu_write(xen_cr3, cr3); |
| |
| /* Update xen_current_cr3 once the batch has actually |
| been submitted. */ |
| xen_mc_callback(set_current_cr3, (void *)cr3); |
| } |
| } |
| |
| static void xen_write_cr3(unsigned long cr3) |
| { |
| BUG_ON(preemptible()); |
| |
| xen_mc_batch(); /* disables interrupts */ |
| |
| /* Update while interrupts are disabled, so its atomic with |
| respect to ipis */ |
| this_cpu_write(xen_cr3, cr3); |
| |
| __xen_write_cr3(true, cr3); |
| |
| #ifdef CONFIG_X86_64 |
| { |
| pgd_t *user_pgd = xen_get_user_pgd(__va(cr3)); |
| if (user_pgd) |
| __xen_write_cr3(false, __pa(user_pgd)); |
| else |
| __xen_write_cr3(false, 0); |
| } |
| #endif |
| |
| xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */ |
| } |
| |
| static int xen_pgd_alloc(struct mm_struct *mm) |
| { |
| pgd_t *pgd = mm->pgd; |
| int ret = 0; |
| |
| BUG_ON(PagePinned(virt_to_page(pgd))); |
| |
| #ifdef CONFIG_X86_64 |
| { |
| struct page *page = virt_to_page(pgd); |
| pgd_t *user_pgd; |
| |
| BUG_ON(page->private != 0); |
| |
| ret = -ENOMEM; |
| |
| user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); |
| page->private = (unsigned long)user_pgd; |
| |
| if (user_pgd != NULL) { |
| user_pgd[pgd_index(VSYSCALL_START)] = |
| __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE); |
| ret = 0; |
| } |
| |
| BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd)))); |
| } |
| #endif |
| |
| return ret; |
| } |
| |
| static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd) |
| { |
| #ifdef CONFIG_X86_64 |
| pgd_t *user_pgd = xen_get_user_pgd(pgd); |
| |
| if (user_pgd) |
| free_page((unsigned long)user_pgd); |
| #endif |
| } |
| |
| #ifdef CONFIG_X86_32 |
| static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte) |
| { |
| /* If there's an existing pte, then don't allow _PAGE_RW to be set */ |
| if (pte_val_ma(*ptep) & _PAGE_PRESENT) |
| pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & |
| pte_val_ma(pte)); |
| |
| return pte; |
| } |
| #else /* CONFIG_X86_64 */ |
| static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte) |
| { |
| unsigned long pfn = pte_pfn(pte); |
| |
| /* |
| * If the new pfn is within the range of the newly allocated |
| * kernel pagetable, and it isn't being mapped into an |
| * early_ioremap fixmap slot as a freshly allocated page, make sure |
| * it is RO. |
| */ |
| if (((!is_early_ioremap_ptep(ptep) && |
| pfn >= pgt_buf_start && pfn < pgt_buf_top)) || |
| (is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1))) |
| pte = pte_wrprotect(pte); |
| |
| return pte; |
| } |
| #endif /* CONFIG_X86_64 */ |
| |
| /* Init-time set_pte while constructing initial pagetables, which |
| doesn't allow RO pagetable pages to be remapped RW */ |
| static void __init xen_set_pte_init(pte_t *ptep, pte_t pte) |
| { |
| pte = mask_rw_pte(ptep, pte); |
| |
| xen_set_pte(ptep, pte); |
| } |
| |
| static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn) |
| { |
| struct mmuext_op op; |
| op.cmd = cmd; |
| op.arg1.mfn = pfn_to_mfn(pfn); |
| if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) |
| BUG(); |
| } |
| |
| /* Early in boot, while setting up the initial pagetable, assume |
| everything is pinned. */ |
| static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn) |
| { |
| #ifdef CONFIG_FLATMEM |
| BUG_ON(mem_map); /* should only be used early */ |
| #endif |
| make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); |
| pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); |
| } |
| |
| /* Used for pmd and pud */ |
| static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn) |
| { |
| #ifdef CONFIG_FLATMEM |
| BUG_ON(mem_map); /* should only be used early */ |
| #endif |
| make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); |
| } |
| |
| /* Early release_pte assumes that all pts are pinned, since there's |
| only init_mm and anything attached to that is pinned. */ |
| static void __init xen_release_pte_init(unsigned long pfn) |
| { |
| pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); |
| make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); |
| } |
| |
| static void __init xen_release_pmd_init(unsigned long pfn) |
| { |
| make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); |
| } |
| |
| static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn) |
| { |
| struct multicall_space mcs; |
| struct mmuext_op *op; |
| |
| mcs = __xen_mc_entry(sizeof(*op)); |
| op = mcs.args; |
| op->cmd = cmd; |
| op->arg1.mfn = pfn_to_mfn(pfn); |
| |
| MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); |
| } |
| |
| static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot) |
| { |
| struct multicall_space mcs; |
| unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT); |
| |
| mcs = __xen_mc_entry(0); |
| MULTI_update_va_mapping(mcs.mc, (unsigned long)addr, |
| pfn_pte(pfn, prot), 0); |
| } |
| |
| /* This needs to make sure the new pte page is pinned iff its being |
| attached to a pinned pagetable. */ |
| static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, |
| unsigned level) |
| { |
| bool pinned = PagePinned(virt_to_page(mm->pgd)); |
| |
| trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned); |
| |
| if (pinned) { |
| struct page *page = pfn_to_page(pfn); |
| |
| SetPagePinned(page); |
| |
| if (!PageHighMem(page)) { |
| xen_mc_batch(); |
| |
| __set_pfn_prot(pfn, PAGE_KERNEL_RO); |
| |
| if (level == PT_PTE && USE_SPLIT_PTLOCKS) |
| __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } else { |
| /* make sure there are no stray mappings of |
| this page */ |
| kmap_flush_unused(); |
| } |
| } |
| } |
| |
| static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn) |
| { |
| xen_alloc_ptpage(mm, pfn, PT_PTE); |
| } |
| |
| static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn) |
| { |
| xen_alloc_ptpage(mm, pfn, PT_PMD); |
| } |
| |
| /* This should never happen until we're OK to use struct page */ |
| static inline void xen_release_ptpage(unsigned long pfn, unsigned level) |
| { |
| struct page *page = pfn_to_page(pfn); |
| bool pinned = PagePinned(page); |
| |
| trace_xen_mmu_release_ptpage(pfn, level, pinned); |
| |
| if (pinned) { |
| if (!PageHighMem(page)) { |
| xen_mc_batch(); |
| |
| if (level == PT_PTE && USE_SPLIT_PTLOCKS) |
| __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); |
| |
| __set_pfn_prot(pfn, PAGE_KERNEL); |
| |
| xen_mc_issue(PARAVIRT_LAZY_MMU); |
| } |
| ClearPagePinned(page); |
| } |
| } |
| |
| static void xen_release_pte(unsigned long pfn) |
| { |
| xen_release_ptpage(pfn, PT_PTE); |
| } |
| |
| static void xen_release_pmd(unsigned long pfn) |
| { |
| xen_release_ptpage(pfn, PT_PMD); |
| } |
| |
| #if PAGETABLE_LEVELS == 4 |
| static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn) |
| { |
| xen_alloc_ptpage(mm, pfn, PT_PUD); |
| } |
| |
| static void xen_release_pud(unsigned long pfn) |
| { |
| xen_release_ptpage(pfn, PT_PUD); |
| } |
| #endif |
| |
| void __init xen_reserve_top(void) |
| { |
| #ifdef CONFIG_X86_32 |
| unsigned long top = HYPERVISOR_VIRT_START; |
| struct xen_platform_parameters pp; |
| |
| if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0) |
| top = pp.virt_start; |
| |
| reserve_top_address(-top); |
| #endif /* CONFIG_X86_32 */ |
| } |
| |
| /* |
| * Like __va(), but returns address in the kernel mapping (which is |
| * all we have until the physical memory mapping has been set up. |
| */ |
| static void *__ka(phys_addr_t paddr) |
| { |
| #ifdef CONFIG_X86_64 |
| return (void *)(paddr + __START_KERNEL_map); |
| #else |
| return __va(paddr); |
| #endif |
| } |
| |
| /* Convert a machine address to physical address */ |
| static unsigned long m2p(phys_addr_t maddr) |
| { |
| phys_addr_t paddr; |
| |
| maddr &= PTE_PFN_MASK; |
| paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT; |
| |
| return paddr; |
| } |
| |
| /* Convert a machine address to kernel virtual */ |
| static void *m2v(phys_addr_t maddr) |
| { |
| return __ka(m2p(maddr)); |
| } |
| |
| /* Set the page permissions on an identity-mapped pages */ |
| static void set_page_prot(void *addr, pgprot_t prot) |
| { |
| unsigned long pfn = __pa(addr) >> PAGE_SHIFT; |
| pte_t pte = pfn_pte(pfn, prot); |
| |
| if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0)) |
| BUG(); |
| } |
| #ifdef CONFIG_X86_32 |
| static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) |
| { |
| unsigned pmdidx, pteidx; |
| unsigned ident_pte; |
| unsigned long pfn; |
| |
| level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES, |
| PAGE_SIZE); |
| |
| ident_pte = 0; |
| pfn = 0; |
| for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) { |
| pte_t *pte_page; |
| |
| /* Reuse or allocate a page of ptes */ |
| if (pmd_present(pmd[pmdidx])) |
| pte_page = m2v(pmd[pmdidx].pmd); |
| else { |
| /* Check for free pte pages */ |
| if (ident_pte == LEVEL1_IDENT_ENTRIES) |
| break; |
| |
| pte_page = &level1_ident_pgt[ident_pte]; |
| ident_pte += PTRS_PER_PTE; |
| |
| pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE); |
| } |
| |
| /* Install mappings */ |
| for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) { |
| pte_t pte; |
| |
| #ifdef CONFIG_X86_32 |
| if (pfn > max_pfn_mapped) |
| max_pfn_mapped = pfn; |
| #endif |
| |
| if (!pte_none(pte_page[pteidx])) |
| continue; |
| |
| pte = pfn_pte(pfn, PAGE_KERNEL_EXEC); |
| pte_page[pteidx] = pte; |
| } |
| } |
| |
| for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE) |
| set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO); |
| |
| set_page_prot(pmd, PAGE_KERNEL_RO); |
| } |
| #endif |
| void __init xen_setup_machphys_mapping(void) |
| { |
| struct xen_machphys_mapping mapping; |
| |
| if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) { |
| machine_to_phys_mapping = (unsigned long *)mapping.v_start; |
| machine_to_phys_nr = mapping.max_mfn + 1; |
| } else { |
| machine_to_phys_nr = MACH2PHYS_NR_ENTRIES; |
| } |
| #ifdef CONFIG_X86_32 |
| WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1)) |
| < machine_to_phys_mapping); |
| #endif |
| } |
| |
| #ifdef CONFIG_X86_64 |
| static void convert_pfn_mfn(void *v) |
| { |
| pte_t *pte = v; |
| int i; |
| |
| /* All levels are converted the same way, so just treat them |
| as ptes. */ |
| for (i = 0; i < PTRS_PER_PTE; i++) |
| pte[i] = xen_make_pte(pte[i].pte); |
| } |
| static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end, |
| unsigned long addr) |
| { |
| if (*pt_base == PFN_DOWN(__pa(addr))) { |
| set_page_prot((void *)addr, PAGE_KERNEL); |
| clear_page((void *)addr); |
| (*pt_base)++; |
| } |
| if (*pt_end == PFN_DOWN(__pa(addr))) { |
| set_page_prot((void *)addr, PAGE_KERNEL); |
| clear_page((void *)addr); |
| (*pt_end)--; |
| } |
| } |
| /* |
| * Set up the initial kernel pagetable. |
| * |
| * We can construct this by grafting the Xen provided pagetable into |
| * head_64.S's preconstructed pagetables. We copy the Xen L2's into |
| * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt. This |
| * means that only the kernel has a physical mapping to start with - |
| * but that's enough to get __va working. We need to fill in the rest |
| * of the physical mapping once some sort of allocator has been set |
| * up. |
| */ |
| void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) |
| { |
| pud_t *l3; |
| pmd_t *l2; |
| unsigned long addr[3]; |
| unsigned long pt_base, pt_end; |
| unsigned i; |
| |
| /* max_pfn_mapped is the last pfn mapped in the initial memory |
| * mappings. Considering that on Xen after the kernel mappings we |
| * have the mappings of some pages that don't exist in pfn space, we |
| * set max_pfn_mapped to the last real pfn mapped. */ |
| max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list)); |
| |
| pt_base = PFN_DOWN(__pa(xen_start_info->pt_base)); |
| pt_end = pt_base + xen_start_info->nr_pt_frames; |
| |
| /* Zap identity mapping */ |
| init_level4_pgt[0] = __pgd(0); |
| |
| /* Pre-constructed entries are in pfn, so convert to mfn */ |
| /* L4[272] -> level3_ident_pgt |
| * L4[511] -> level3_kernel_pgt */ |
| convert_pfn_mfn(init_level4_pgt); |
| |
| /* L3_i[0] -> level2_ident_pgt */ |
| convert_pfn_mfn(level3_ident_pgt); |
| /* L3_k[510] -> level2_kernel_pgt |
| * L3_i[511] -> level2_fixmap_pgt */ |
| convert_pfn_mfn(level3_kernel_pgt); |
| |
| /* We get [511][511] and have Xen's version of level2_kernel_pgt */ |
| l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd); |
| l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud); |
| |
| addr[0] = (unsigned long)pgd; |
| addr[1] = (unsigned long)l3; |
| addr[2] = (unsigned long)l2; |
| /* Graft it onto L4[272][0]. Note that we creating an aliasing problem: |
| * Both L4[272][0] and L4[511][511] have entries that point to the same |
| * L2 (PMD) tables. Meaning that if you modify it in __va space |
| * it will be also modified in the __ka space! (But if you just |
| * modify the PMD table to point to other PTE's or none, then you |
| * are OK - which is what cleanup_highmap does) */ |
| copy_page(level2_ident_pgt, l2); |
| /* Graft it onto L4[511][511] */ |
| copy_page(level2_kernel_pgt, l2); |
| |
| /* Get [511][510] and graft that in level2_fixmap_pgt */ |
| l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd); |
| l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud); |
| copy_page(level2_fixmap_pgt, l2); |
| /* Note that we don't do anything with level1_fixmap_pgt which |
| * we don't need. */ |
| |
| /* Make pagetable pieces RO */ |
| set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); |
| set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); |
| set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); |
| set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO); |
| set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); |
| set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); |
| set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); |
| |
| /* Pin down new L4 */ |
| pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, |
| PFN_DOWN(__pa_symbol(init_level4_pgt))); |
| |
| /* Unpin Xen-provided one */ |
| pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); |
| |
| /* |
| * At this stage there can be no user pgd, and no page |
| * structure to attach it to, so make sure we just set kernel |
| * pgd. |
| */ |
| xen_mc_batch(); |
| __xen_write_cr3(true, __pa(init_level4_pgt)); |
| xen_mc_issue(PARAVIRT_LAZY_CPU); |
| |
| /* We can't that easily rip out L3 and L2, as the Xen pagetables are |
| * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for |
| * the initial domain. For guests using the toolstack, they are in: |
| * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only |
| * rip out the [L4] (pgd), but for guests we shave off three pages. |
| */ |
| for (i = 0; i < ARRAY_SIZE(addr); i++) |
| check_pt_base(&pt_base, &pt_end, addr[i]); |
| |
| /* Our (by three pages) smaller Xen pagetable that we are using */ |
| memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE); |
| /* Revector the xen_start_info */ |
| xen_start_info = (struct start_info *)__va(__pa(xen_start_info)); |
| } |
| #else /* !CONFIG_X86_64 */ |
| static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD); |
| static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD); |
| |
| static void __init xen_write_cr3_init(unsigned long cr3) |
| { |
| unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir)); |
| |
| BUG_ON(read_cr3() != __pa(initial_page_table)); |
| BUG_ON(cr3 != __pa(swapper_pg_dir)); |
| |
| /* |
| * We are switching to swapper_pg_dir for the first time (from |
| * initial_page_table) and therefore need to mark that page |
| * read-only and then pin it. |
| * |
| * Xen disallows sharing of kernel PMDs for PAE |
| * guests. Therefore we must copy the kernel PMD from |
| * initial_page_table into a new kernel PMD to be used in |
| * swapper_pg_dir. |
| */ |
| swapper_kernel_pmd = |
| extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); |
| copy_page(swapper_kernel_pmd, initial_kernel_pmd); |
| swapper_pg_dir[KERNEL_PGD_BOUNDARY] = |
| __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); |
| set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO); |
| |
| set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO); |
| xen_write_cr3(cr3); |
| pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn); |
| |
| pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, |
| PFN_DOWN(__pa(initial_page_table))); |
| set_page_prot(initial_page_table, PAGE_KERNEL); |
| set_page_prot(initial_kernel_pmd, PAGE_KERNEL); |
| |
| pv_mmu_ops.write_cr3 = &xen_write_cr3; |
| } |
| |
| void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) |
| { |
| pmd_t *kernel_pmd; |
| |
| initial_kernel_pmd = |
| extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); |
| |
| max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) + |
| xen_start_info->nr_pt_frames * PAGE_SIZE + |
| 512*1024); |
| |
| kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd); |
| copy_page(initial_kernel_pmd, kernel_pmd); |
| |
| xen_map_identity_early(initial_kernel_pmd, max_pfn); |
| |
| copy_page(initial_page_table, pgd); |
| initial_page_table[KERNEL_PGD_BOUNDARY] = |
| __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT); |
| |
| set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO); |
| set_page_prot(initial_page_table, PAGE_KERNEL_RO); |
| set_page_prot(empty_zero_page, PAGE_KERNEL_RO); |
| |
| pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); |
| |
| pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, |
| PFN_DOWN(__pa(initial_page_table))); |
| xen_write_cr3(__pa(initial_page_table)); |
| |
| memblock_reserve(__pa(xen_start_info->pt_base), |
| xen_start_info->nr_pt_frames * PAGE_SIZE); |
| } |
| #endif /* CONFIG_X86_64 */ |
| |
| static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss; |
| |
| static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) |
| { |
| pte_t pte; |
| |
| phys >>= PAGE_SHIFT; |
| |
| switch (idx) { |
| case FIX_BTMAP_END ... FIX_BTMAP_BEGIN: |
| #ifdef CONFIG_X86_F00F_BUG |
| case FIX_F00F_IDT: |
| #endif |
| #ifdef CONFIG_X86_32 |
| case FIX_WP_TEST: |
| case FIX_VDSO: |
| # ifdef CONFIG_HIGHMEM |
| case FIX_KMAP_BEGIN ... FIX_KMAP_END: |
| # endif |
| #else |
| case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE: |
| case VVAR_PAGE: |
| #endif |
| case FIX_TEXT_POKE0: |
| case FIX_TEXT_POKE1: |
| /* All local page mappings */ |
| pte = pfn_pte(phys, prot); |
| break; |
| |
| #ifdef CONFIG_X86_LOCAL_APIC |
| case FIX_APIC_BASE: /* maps dummy local APIC */ |
| pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL); |
| break; |
| #endif |
| |
| #ifdef CONFIG_X86_IO_APIC |
| case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END: |
| /* |
| * We just don't map the IO APIC - all access is via |
| * hypercalls. Keep the address in the pte for reference. |
| */ |
| pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL); |
| break; |
| #endif |
| |
| case FIX_PARAVIRT_BOOTMAP: |
| /* This is an MFN, but it isn't an IO mapping from the |
| IO domain */ |
| pte = mfn_pte(phys, prot); |
| break; |
| |
| default: |
| /* By default, set_fixmap is used for hardware mappings */ |
| pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP)); |
| break; |
| } |
| |
| __native_set_fixmap(idx, pte); |
| |
| #ifdef CONFIG_X86_64 |
| /* Replicate changes to map the vsyscall page into the user |
| pagetable vsyscall mapping. */ |
| if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) || |
| idx == VVAR_PAGE) { |
| unsigned long vaddr = __fix_to_virt(idx); |
| set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte); |
| } |
| #endif |
| } |
| |
| static void __init xen_post_allocator_init(void) |
| { |
| pv_mmu_ops.set_pte = xen_set_pte; |
| pv_mmu_ops.set_pmd = xen_set_pmd; |
| pv_mmu_ops.set_pud = xen_set_pud; |
| #if PAGETABLE_LEVELS == 4 |
| pv_mmu_ops.set_pgd = xen_set_pgd; |
| #endif |
| |
| /* This will work as long as patching hasn't happened yet |
| (which it hasn't) */ |
| pv_mmu_ops.alloc_pte = xen_alloc_pte; |
| pv_mmu_ops.alloc_pmd = xen_alloc_pmd; |
| pv_mmu_ops.release_pte = xen_release_pte; |
| pv_mmu_ops.release_pmd = xen_release_pmd; |
| #if PAGETABLE_LEVELS == 4 |
| pv_mmu_ops.alloc_pud = xen_alloc_pud; |
| pv_mmu_ops.release_pud = xen_release_pud; |
| #endif |
| |
| #ifdef CONFIG_X86_64 |
| SetPagePinned(virt_to_page(level3_user_vsyscall)); |
| #endif |
| xen_mark_init_mm_pinned(); |
| } |
| |
| static void xen_leave_lazy_mmu(void) |
| { |
| preempt_disable(); |
| xen_mc_flush(); |
| paravirt_leave_lazy_mmu(); |
| preempt_enable(); |
| } |
| |
| static const struct pv_mmu_ops xen_mmu_ops __initconst = { |
| .read_cr2 = xen_read_cr2, |
| .write_cr2 = xen_write_cr2, |
| |
| .read_cr3 = xen_read_cr3, |
| #ifdef CONFIG_X86_32 |
| .write_cr3 = xen_write_cr3_init, |
| #else |
| .write_cr3 = xen_write_cr3, |
| #endif |
| |
| .flush_tlb_user = xen_flush_tlb, |
| .flush_tlb_kernel = xen_flush_tlb, |
| .flush_tlb_single = xen_flush_tlb_single, |
| .flush_tlb_others = xen_flush_tlb_others, |
| |
| .pte_update = paravirt_nop, |
| .pte_update_defer = paravirt_nop, |
| |
| .pgd_alloc = xen_pgd_alloc, |
| .pgd_free = xen_pgd_free, |
| |
| .alloc_pte = xen_alloc_pte_init, |
| .release_pte = xen_release_pte_init, |
| .alloc_pmd = xen_alloc_pmd_init, |
| .release_pmd = xen_release_pmd_init, |
| |
| .set_pte = xen_set_pte_init, |
| .set_pte_at = xen_set_pte_at, |
| .set_pmd = xen_set_pmd_hyper, |
| |
| .ptep_modify_prot_start = __ptep_modify_prot_start, |
| .ptep_modify_prot_commit = __ptep_modify_prot_commit, |
| |
| .pte_val = PV_CALLEE_SAVE(xen_pte_val), |
| .pgd_val = PV_CALLEE_SAVE(xen_pgd_val), |
| |
| .make_pte = PV_CALLEE_SAVE(xen_make_pte), |
| .make_pgd = PV_CALLEE_SAVE(xen_make_pgd), |
| |
| #ifdef CONFIG_X86_PAE |
| .set_pte_atomic = xen_set_pte_atomic, |
| .pte_clear = xen_pte_clear, |
| .pmd_clear = xen_pmd_clear, |
| #endif /* CONFIG_X86_PAE */ |
| .set_pud = xen_set_pud_hyper, |
| |
| .make_pmd = PV_CALLEE_SAVE(xen_make_pmd), |
| .pmd_val = PV_CALLEE_SAVE(xen_pmd_val), |
| |
| #if PAGETABLE_LEVELS == 4 |
| .pud_val = PV_CALLEE_SAVE(xen_pud_val), |
| .make_pud = PV_CALLEE_SAVE(xen_make_pud), |
| .set_pgd = xen_set_pgd_hyper, |
| |
| .alloc_pud = xen_alloc_pmd_init, |
| .release_pud = xen_release_pmd_init, |
| #endif /* PAGETABLE_LEVELS == 4 */ |
| |
| .activate_mm = xen_activate_mm, |
| .dup_mmap = xen_dup_mmap, |
| .exit_mmap = xen_exit_mmap, |
| |
| .lazy_mode = { |
| .enter = paravirt_enter_lazy_mmu, |
| .leave = xen_leave_lazy_mmu, |
| }, |
| |
| .set_fixmap = xen_set_fixmap, |
| }; |
| |
| void __init xen_init_mmu_ops(void) |
| { |
| x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve; |
| x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start; |
| x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done; |
| pv_mmu_ops = xen_mmu_ops; |
| |
| memset(dummy_mapping, 0xff, PAGE_SIZE); |
| } |
| |
| /* Protected by xen_reservation_lock. */ |
| #define MAX_CONTIG_ORDER 9 /* 2MB */ |
| static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER]; |
| |
| #define VOID_PTE (mfn_pte(0, __pgprot(0))) |
| static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order, |
| unsigned long *in_frames, |
| unsigned long *out_frames) |
| { |
| int i; |
| struct multicall_space mcs; |
| |
| xen_mc_batch(); |
| for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) { |
| mcs = __xen_mc_entry(0); |
| |
| if (in_frames) |
| in_frames[i] = virt_to_mfn(vaddr); |
| |
| MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0); |
| __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY); |
| |
| if (out_frames) |
| out_frames[i] = virt_to_pfn(vaddr); |
| } |
| xen_mc_issue(0); |
| } |
| |
| /* |
| * Update the pfn-to-mfn mappings for a virtual address range, either to |
| * point to an array of mfns, or contiguously from a single starting |
| * mfn. |
| */ |
| static void xen_remap_exchanged_ptes(unsigned long vaddr, int order, |
| unsigned long *mfns, |
| unsigned long first_mfn) |
| { |
| unsigned i, limit; |
| unsigned long mfn; |
| |
| xen_mc_batch(); |
| |
| limit = 1u << order; |
| for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) { |
| struct multicall_space mcs; |
| unsigned flags; |
| |
| mcs = __xen_mc_entry(0); |
| if (mfns) |
| mfn = mfns[i]; |
| else |
| mfn = first_mfn + i; |
| |
| if (i < (limit - 1)) |
| flags = 0; |
| else { |
| if (order == 0) |
| flags = UVMF_INVLPG | UVMF_ALL; |
| else |
| flags = UVMF_TLB_FLUSH | UVMF_ALL; |
| } |
| |
| MULTI_update_va_mapping(mcs.mc, vaddr, |
| mfn_pte(mfn, PAGE_KERNEL), flags); |
| |
| set_phys_to_machine(virt_to_pfn(vaddr), mfn); |
| } |
| |
| xen_mc_issue(0); |
| } |
| |
| /* |
| * Perform the hypercall to exchange a region of our pfns to point to |
| * memory with the required contiguous alignment. Takes the pfns as |
| * input, and populates mfns as output. |
| * |
| * Returns a success code indicating whether the hypervisor was able to |
| * satisfy the request or not. |
| */ |
| static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in, |
| unsigned long *pfns_in, |
| unsigned long extents_out, |
| unsigned int order_out, |
| unsigned long *mfns_out, |
| unsigned int address_bits) |
| { |
| long rc; |
| int success; |
| |
| struct xen_memory_exchange exchange = { |
| .in = { |
| .nr_extents = extents_in, |
| .extent_order = order_in, |
| .extent_start = pfns_in, |
| .domid = DOMID_SELF |
| }, |
| .out = { |
| .nr_extents = extents_out, |
| .extent_order = order_out, |
| .extent_start = mfns_out, |
| .address_bits = address_bits, |
| .domid = DOMID_SELF |
| } |
| }; |
| |
| BUG_ON(extents_in << order_in != extents_out << order_out); |
| |
| rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange); |
| success = (exchange.nr_exchanged == extents_in); |
| |
| BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0))); |
| BUG_ON(success && (rc != 0)); |
| |
| return success; |
| } |
| |
| int xen_create_contiguous_region(unsigned long vstart, unsigned int order, |
| unsigned int address_bits) |
| { |
| unsigned long *in_frames = discontig_frames, out_frame; |
| unsigned long flags; |
| int success; |
| |
| /* |
| * Currently an auto-translated guest will not perform I/O, nor will |
| * it require PAE page directories below 4GB. Therefore any calls to |
| * this function are redundant and can be ignored. |
| */ |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return 0; |
| |
| if (unlikely(order > MAX_CONTIG_ORDER)) |
| return -ENOMEM; |
| |
| memset((void *) vstart, 0, PAGE_SIZE << order); |
| |
| spin_lock_irqsave(&xen_reservation_lock, flags); |
| |
| /* 1. Zap current PTEs, remembering MFNs. */ |
| xen_zap_pfn_range(vstart, order, in_frames, NULL); |
| |
| /* 2. Get a new contiguous memory extent. */ |
| out_frame = virt_to_pfn(vstart); |
| success = xen_exchange_memory(1UL << order, 0, in_frames, |
| 1, order, &out_frame, |
| address_bits); |
| |
| /* 3. Map the new extent in place of old pages. */ |
| if (success) |
| xen_remap_exchanged_ptes(vstart, order, NULL, out_frame); |
| else |
| xen_remap_exchanged_ptes(vstart, order, in_frames, 0); |
| |
| spin_unlock_irqrestore(&xen_reservation_lock, flags); |
| |
| return success ? 0 : -ENOMEM; |
| } |
| EXPORT_SYMBOL_GPL(xen_create_contiguous_region); |
| |
| void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) |
| { |
| unsigned long *out_frames = discontig_frames, in_frame; |
| unsigned long flags; |
| int success; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return; |
| |
| if (unlikely(order > MAX_CONTIG_ORDER)) |
| return; |
| |
| memset((void *) vstart, 0, PAGE_SIZE << order); |
| |
| spin_lock_irqsave(&xen_reservation_lock, flags); |
| |
| /* 1. Find start MFN of contiguous extent. */ |
| in_frame = virt_to_mfn(vstart); |
| |
| /* 2. Zap current PTEs. */ |
| xen_zap_pfn_range(vstart, order, NULL, out_frames); |
| |
| /* 3. Do the exchange for non-contiguous MFNs. */ |
| success = xen_exchange_memory(1, order, &in_frame, 1UL << order, |
| 0, out_frames, 0); |
| |
| /* 4. Map new pages in place of old pages. */ |
| if (success) |
| xen_remap_exchanged_ptes(vstart, order, out_frames, 0); |
| else |
| xen_remap_exchanged_ptes(vstart, order, NULL, in_frame); |
| |
| spin_unlock_irqrestore(&xen_reservation_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); |
| |
| #ifdef CONFIG_XEN_PVHVM |
| static void xen_hvm_exit_mmap(struct mm_struct *mm) |
| { |
| struct xen_hvm_pagetable_dying a; |
| int rc; |
| |
| a.domid = DOMID_SELF; |
| a.gpa = __pa(mm->pgd); |
| rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); |
| WARN_ON_ONCE(rc < 0); |
| } |
| |
| static int is_pagetable_dying_supported(void) |
| { |
| struct xen_hvm_pagetable_dying a; |
| int rc = 0; |
| |
| a.domid = DOMID_SELF; |
| a.gpa = 0x00; |
| rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); |
| if (rc < 0) { |
| printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n"); |
| return 0; |
| } |
| return 1; |
| } |
| |
| void __init xen_hvm_init_mmu_ops(void) |
| { |
| if (is_pagetable_dying_supported()) |
| pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap; |
| } |
| #endif |
| |
| #define REMAP_BATCH_SIZE 16 |
| |
| struct remap_data { |
| unsigned long mfn; |
| pgprot_t prot; |
| struct mmu_update *mmu_update; |
| }; |
| |
| static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token, |
| unsigned long addr, void *data) |
| { |
| struct remap_data *rmd = data; |
| pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot)); |
| |
| rmd->mmu_update->ptr = virt_to_machine(ptep).maddr; |
| rmd->mmu_update->val = pte_val_ma(pte); |
| rmd->mmu_update++; |
| |
| return 0; |
| } |
| |
| int xen_remap_domain_mfn_range(struct vm_area_struct *vma, |
| unsigned long addr, |
| unsigned long mfn, int nr, |
| pgprot_t prot, unsigned domid) |
| { |
| struct remap_data rmd; |
| struct mmu_update mmu_update[REMAP_BATCH_SIZE]; |
| int batch; |
| unsigned long range; |
| int err = 0; |
| |
| prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP); |
| |
| BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) == |
| (VM_PFNMAP | VM_RESERVED | VM_IO))); |
| |
| rmd.mfn = mfn; |
| rmd.prot = prot; |
| |
| while (nr) { |
| batch = min(REMAP_BATCH_SIZE, nr); |
| range = (unsigned long)batch << PAGE_SHIFT; |
| |
| rmd.mmu_update = mmu_update; |
| err = apply_to_page_range(vma->vm_mm, addr, range, |
| remap_area_mfn_pte_fn, &rmd); |
| if (err) |
| goto out; |
| |
| err = -EFAULT; |
| if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0) |
| goto out; |
| |
| nr -= batch; |
| addr += range; |
| } |
| |
| err = 0; |
| out: |
| |
| flush_tlb_all(); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range); |