/release/src-rt/linux/linux-2.6/drivers/kvm/paging_tmpl.h
C Header | 484 lines | 350 code | 58 blank | 76 comment | 75 complexity | efda0adf32ae98457ca8b767f55b40a4 MD5 | raw file
- /*
- * Kernel-based Virtual Machine driver for Linux
- *
- * This module enables machines with Intel VT-x extensions to run virtual
- * machines without emulation or binary translation.
- *
- * MMU support
- *
- * Copyright (C) 2006 Qumranet, Inc.
- *
- * Authors:
- * Yaniv Kamay <yaniv@qumranet.com>
- * Avi Kivity <avi@qumranet.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2. See
- * the COPYING file in the top-level directory.
- *
- */
- /*
- * We need the mmu code to access both 32-bit and 64-bit guest ptes,
- * so the code in this file is compiled twice, once per pte size.
- */
- #if PTTYPE == 64
- #define pt_element_t u64
- #define guest_walker guest_walker64
- #define FNAME(name) paging##64_##name
- #define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
- #define PT_DIR_BASE_ADDR_MASK PT64_DIR_BASE_ADDR_MASK
- #define PT_INDEX(addr, level) PT64_INDEX(addr, level)
- #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
- #define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)
- #define PT_PTE_COPY_MASK PT64_PTE_COPY_MASK
- #ifdef CONFIG_X86_64
- #define PT_MAX_FULL_LEVELS 4
- #else
- #define PT_MAX_FULL_LEVELS 2
- #endif
- #elif PTTYPE == 32
- #define pt_element_t u32
- #define guest_walker guest_walker32
- #define FNAME(name) paging##32_##name
- #define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
- #define PT_DIR_BASE_ADDR_MASK PT32_DIR_BASE_ADDR_MASK
- #define PT_INDEX(addr, level) PT32_INDEX(addr, level)
- #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
- #define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
- #define PT_PTE_COPY_MASK PT32_PTE_COPY_MASK
- #define PT_MAX_FULL_LEVELS 2
- #else
- #error Invalid PTTYPE value
- #endif
- /*
- * The guest_walker structure emulates the behavior of the hardware page
- * table walker.
- */
- struct guest_walker {
- int level;
- gfn_t table_gfn[PT_MAX_FULL_LEVELS];
- pt_element_t *table;
- pt_element_t *ptep;
- pt_element_t inherited_ar;
- gfn_t gfn;
- u32 error_code;
- };
- /*
- * Fetch a guest pte for a guest virtual address
- */
- static int FNAME(walk_addr)(struct guest_walker *walker,
- struct kvm_vcpu *vcpu, gva_t addr,
- int write_fault, int user_fault, int fetch_fault)
- {
- hpa_t hpa;
- struct kvm_memory_slot *slot;
- pt_element_t *ptep;
- pt_element_t root;
- gfn_t table_gfn;
- pgprintk("%s: addr %lx\n", __FUNCTION__, addr);
- walker->level = vcpu->mmu.root_level;
- walker->table = NULL;
- root = vcpu->cr3;
- #if PTTYPE == 64
- if (!is_long_mode(vcpu)) {
- walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3];
- root = *walker->ptep;
- if (!(root & PT_PRESENT_MASK))
- goto not_present;
- --walker->level;
- }
- #endif
- table_gfn = (root & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
- walker->table_gfn[walker->level - 1] = table_gfn;
- pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,
- walker->level - 1, table_gfn);
- slot = gfn_to_memslot(vcpu->kvm, table_gfn);
- hpa = safe_gpa_to_hpa(vcpu, root & PT64_BASE_ADDR_MASK);
- walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0);
- ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
- (vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) == 0);
- walker->inherited_ar = PT_USER_MASK | PT_WRITABLE_MASK;
- for (;;) {
- int index = PT_INDEX(addr, walker->level);
- hpa_t paddr;
- ptep = &walker->table[index];
- ASSERT(((unsigned long)walker->table & PAGE_MASK) ==
- ((unsigned long)ptep & PAGE_MASK));
- if (!is_present_pte(*ptep))
- goto not_present;
- if (write_fault && !is_writeble_pte(*ptep))
- if (user_fault || is_write_protection(vcpu))
- goto access_error;
- if (user_fault && !(*ptep & PT_USER_MASK))
- goto access_error;
- #if PTTYPE == 64
- if (fetch_fault && is_nx(vcpu) && (*ptep & PT64_NX_MASK))
- goto access_error;
- #endif
- if (!(*ptep & PT_ACCESSED_MASK)) {
- mark_page_dirty(vcpu->kvm, table_gfn);
- *ptep |= PT_ACCESSED_MASK;
- }
- if (walker->level == PT_PAGE_TABLE_LEVEL) {
- walker->gfn = (*ptep & PT_BASE_ADDR_MASK)
- >> PAGE_SHIFT;
- break;
- }
- if (walker->level == PT_DIRECTORY_LEVEL
- && (*ptep & PT_PAGE_SIZE_MASK)
- && (PTTYPE == 64 || is_pse(vcpu))) {
- walker->gfn = (*ptep & PT_DIR_BASE_ADDR_MASK)
- >> PAGE_SHIFT;
- walker->gfn += PT_INDEX(addr, PT_PAGE_TABLE_LEVEL);
- break;
- }
- walker->inherited_ar &= walker->table[index];
- table_gfn = (*ptep & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;
- paddr = safe_gpa_to_hpa(vcpu, *ptep & PT_BASE_ADDR_MASK);
- kunmap_atomic(walker->table, KM_USER0);
- walker->table = kmap_atomic(pfn_to_page(paddr >> PAGE_SHIFT),
- KM_USER0);
- --walker->level;
- walker->table_gfn[walker->level - 1 ] = table_gfn;
- pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,
- walker->level - 1, table_gfn);
- }
- walker->ptep = ptep;
- pgprintk("%s: pte %llx\n", __FUNCTION__, (u64)*ptep);
- return 1;
- not_present:
- walker->error_code = 0;
- goto err;
- access_error:
- walker->error_code = PFERR_PRESENT_MASK;
- err:
- if (write_fault)
- walker->error_code |= PFERR_WRITE_MASK;
- if (user_fault)
- walker->error_code |= PFERR_USER_MASK;
- if (fetch_fault)
- walker->error_code |= PFERR_FETCH_MASK;
- return 0;
- }
- static void FNAME(release_walker)(struct guest_walker *walker)
- {
- if (walker->table)
- kunmap_atomic(walker->table, KM_USER0);
- }
- static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
- struct guest_walker *walker)
- {
- mark_page_dirty(kvm, walker->table_gfn[walker->level - 1]);
- }
- static void FNAME(set_pte)(struct kvm_vcpu *vcpu, u64 guest_pte,
- u64 *shadow_pte, u64 access_bits, gfn_t gfn)
- {
- ASSERT(*shadow_pte == 0);
- access_bits &= guest_pte;
- *shadow_pte = (guest_pte & PT_PTE_COPY_MASK);
- set_pte_common(vcpu, shadow_pte, guest_pte & PT_BASE_ADDR_MASK,
- guest_pte & PT_DIRTY_MASK, access_bits, gfn);
- }
- static void FNAME(set_pde)(struct kvm_vcpu *vcpu, u64 guest_pde,
- u64 *shadow_pte, u64 access_bits, gfn_t gfn)
- {
- gpa_t gaddr;
- ASSERT(*shadow_pte == 0);
- access_bits &= guest_pde;
- gaddr = (gpa_t)gfn << PAGE_SHIFT;
- if (PTTYPE == 32 && is_cpuid_PSE36())
- gaddr |= (guest_pde & PT32_DIR_PSE36_MASK) <<
- (32 - PT32_DIR_PSE36_SHIFT);
- *shadow_pte = guest_pde & PT_PTE_COPY_MASK;
- set_pte_common(vcpu, shadow_pte, gaddr,
- guest_pde & PT_DIRTY_MASK, access_bits, gfn);
- }
- /*
- * Fetch a shadow pte for a specific level in the paging hierarchy.
- */
- static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
- struct guest_walker *walker)
- {
- hpa_t shadow_addr;
- int level;
- u64 *prev_shadow_ent = NULL;
- pt_element_t *guest_ent = walker->ptep;
- if (!is_present_pte(*guest_ent))
- return NULL;
- shadow_addr = vcpu->mmu.root_hpa;
- level = vcpu->mmu.shadow_root_level;
- if (level == PT32E_ROOT_LEVEL) {
- shadow_addr = vcpu->mmu.pae_root[(addr >> 30) & 3];
- shadow_addr &= PT64_BASE_ADDR_MASK;
- --level;
- }
- for (; ; level--) {
- u32 index = SHADOW_PT_INDEX(addr, level);
- u64 *shadow_ent = ((u64 *)__va(shadow_addr)) + index;
- struct kvm_mmu_page *shadow_page;
- u64 shadow_pte;
- int metaphysical;
- gfn_t table_gfn;
- unsigned hugepage_access = 0;
- if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {
- if (level == PT_PAGE_TABLE_LEVEL)
- return shadow_ent;
- shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
- prev_shadow_ent = shadow_ent;
- continue;
- }
- if (level == PT_PAGE_TABLE_LEVEL) {
- if (walker->level == PT_DIRECTORY_LEVEL) {
- if (prev_shadow_ent)
- *prev_shadow_ent |= PT_SHADOW_PS_MARK;
- FNAME(set_pde)(vcpu, *guest_ent, shadow_ent,
- walker->inherited_ar,
- walker->gfn);
- } else {
- ASSERT(walker->level == PT_PAGE_TABLE_LEVEL);
- FNAME(set_pte)(vcpu, *guest_ent, shadow_ent,
- walker->inherited_ar,
- walker->gfn);
- }
- return shadow_ent;
- }
- if (level - 1 == PT_PAGE_TABLE_LEVEL
- && walker->level == PT_DIRECTORY_LEVEL) {
- metaphysical = 1;
- hugepage_access = *guest_ent;
- hugepage_access &= PT_USER_MASK | PT_WRITABLE_MASK;
- hugepage_access >>= PT_WRITABLE_SHIFT;
- table_gfn = (*guest_ent & PT_BASE_ADDR_MASK)
- >> PAGE_SHIFT;
- } else {
- metaphysical = 0;
- table_gfn = walker->table_gfn[level - 2];
- }
- shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
- metaphysical, hugepage_access,
- shadow_ent);
- shadow_addr = shadow_page->page_hpa;
- shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK
- | PT_WRITABLE_MASK | PT_USER_MASK;
- *shadow_ent = shadow_pte;
- prev_shadow_ent = shadow_ent;
- }
- }
- /*
- * The guest faulted for write. We need to
- *
- * - check write permissions
- * - update the guest pte dirty bit
- * - update our own dirty page tracking structures
- */
- static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu,
- u64 *shadow_ent,
- struct guest_walker *walker,
- gva_t addr,
- int user,
- int *write_pt)
- {
- pt_element_t *guest_ent;
- int writable_shadow;
- gfn_t gfn;
- struct kvm_mmu_page *page;
- if (is_writeble_pte(*shadow_ent))
- return !user || (*shadow_ent & PT_USER_MASK);
- writable_shadow = *shadow_ent & PT_SHADOW_WRITABLE_MASK;
- if (user) {
- /*
- * User mode access. Fail if it's a kernel page or a read-only
- * page.
- */
- if (!(*shadow_ent & PT_SHADOW_USER_MASK) || !writable_shadow)
- return 0;
- ASSERT(*shadow_ent & PT_USER_MASK);
- } else
- /*
- * Kernel mode access. Fail if it's a read-only page and
- * supervisor write protection is enabled.
- */
- if (!writable_shadow) {
- if (is_write_protection(vcpu))
- return 0;
- *shadow_ent &= ~PT_USER_MASK;
- }
- guest_ent = walker->ptep;
- if (!is_present_pte(*guest_ent)) {
- *shadow_ent = 0;
- return 0;
- }
- gfn = walker->gfn;
- if (user) {
- /*
- * Usermode page faults won't be for page table updates.
- */
- while ((page = kvm_mmu_lookup_page(vcpu, gfn)) != NULL) {
- pgprintk("%s: zap %lx %x\n",
- __FUNCTION__, gfn, page->role.word);
- kvm_mmu_zap_page(vcpu, page);
- }
- } else if (kvm_mmu_lookup_page(vcpu, gfn)) {
- pgprintk("%s: found shadow page for %lx, marking ro\n",
- __FUNCTION__, gfn);
- mark_page_dirty(vcpu->kvm, gfn);
- FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
- *guest_ent |= PT_DIRTY_MASK;
- *write_pt = 1;
- return 0;
- }
- mark_page_dirty(vcpu->kvm, gfn);
- *shadow_ent |= PT_WRITABLE_MASK;
- FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
- *guest_ent |= PT_DIRTY_MASK;
- rmap_add(vcpu, shadow_ent);
- return 1;
- }
- /*
- * Page fault handler. There are several causes for a page fault:
- * - there is no shadow pte for the guest pte
- * - write access through a shadow pte marked read only so that we can set
- * the dirty bit
- * - write access to a shadow pte marked read only so we can update the page
- * dirty bitmap, when userspace requests it
- * - mmio access; in this case we will never install a present shadow pte
- * - normal guest page fault due to the guest pte marked not present, not
- * writable, or not executable
- *
- * Returns: 1 if we need to emulate the instruction, 0 otherwise, or
- * a negative value on error.
- */
- static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
- u32 error_code)
- {
- int write_fault = error_code & PFERR_WRITE_MASK;
- int user_fault = error_code & PFERR_USER_MASK;
- int fetch_fault = error_code & PFERR_FETCH_MASK;
- struct guest_walker walker;
- u64 *shadow_pte;
- int fixed;
- int write_pt = 0;
- int r;
- pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code);
- kvm_mmu_audit(vcpu, "pre page fault");
- r = mmu_topup_memory_caches(vcpu);
- if (r)
- return r;
- /*
- * Look up the shadow pte for the faulting address.
- */
- r = FNAME(walk_addr)(&walker, vcpu, addr, write_fault, user_fault,
- fetch_fault);
- /*
- * The page is not mapped by the guest. Let the guest handle it.
- */
- if (!r) {
- pgprintk("%s: guest page fault\n", __FUNCTION__);
- inject_page_fault(vcpu, addr, walker.error_code);
- FNAME(release_walker)(&walker);
- return 0;
- }
- shadow_pte = FNAME(fetch)(vcpu, addr, &walker);
- pgprintk("%s: shadow pte %p %llx\n", __FUNCTION__,
- shadow_pte, *shadow_pte);
- /*
- * Update the shadow pte.
- */
- if (write_fault)
- fixed = FNAME(fix_write_pf)(vcpu, shadow_pte, &walker, addr,
- user_fault, &write_pt);
- else
- fixed = fix_read_pf(shadow_pte);
- pgprintk("%s: updated shadow pte %p %llx\n", __FUNCTION__,
- shadow_pte, *shadow_pte);
- FNAME(release_walker)(&walker);
- /*
- * mmio: emulate if accessible, otherwise its a guest fault.
- */
- if (is_io_pte(*shadow_pte))
- return 1;
- ++vcpu->stat.pf_fixed;
- kvm_mmu_audit(vcpu, "post page fault (fixed)");
- return write_pt;
- }
- static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
- {
- struct guest_walker walker;
- gpa_t gpa = UNMAPPED_GVA;
- int r;
- r = FNAME(walk_addr)(&walker, vcpu, vaddr, 0, 0, 0);
- if (r) {
- gpa = (gpa_t)walker.gfn << PAGE_SHIFT;
- gpa |= vaddr & ~PAGE_MASK;
- }
- FNAME(release_walker)(&walker);
- return gpa;
- }
- #undef pt_element_t
- #undef guest_walker
- #undef FNAME
- #undef PT_BASE_ADDR_MASK
- #undef PT_INDEX
- #undef SHADOW_PT_INDEX
- #undef PT_LEVEL_MASK
- #undef PT_PTE_COPY_MASK
- #undef PT_NON_PTE_COPY_MASK
- #undef PT_DIR_BASE_ADDR_MASK
- #undef PT_MAX_FULL_LEVELS