KVM: MMU: Make flooding detection work when guest page faults are bypassed
[safe/jmp/linux-2.6] / drivers / kvm / paging_tmpl.h
index a7c5cb0..be0f852 100644 (file)
@@ -31,6 +31,7 @@
        #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_LEVEL_BITS PT64_LEVEL_BITS
        #ifdef CONFIG_X86_64
        #define PT_MAX_FULL_LEVELS 4
        #else
@@ -45,6 +46,7 @@
        #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_LEVEL_BITS PT32_LEVEL_BITS
        #define PT_MAX_FULL_LEVELS 2
 #else
        #error Invalid PTTYPE value
@@ -58,7 +60,10 @@ struct guest_walker {
        int level;
        gfn_t table_gfn[PT_MAX_FULL_LEVELS];
        pt_element_t *table;
+       pt_element_t pte;
        pt_element_t *ptep;
+       struct page *page;
+       int index;
        pt_element_t inherited_ar;
        gfn_t gfn;
        u32 error_code;
@@ -80,11 +85,14 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
        pgprintk("%s: addr %lx\n", __FUNCTION__, addr);
        walker->level = vcpu->mmu.root_level;
        walker->table = NULL;
+       walker->page = NULL;
+       walker->ptep = NULL;
        root = vcpu->cr3;
 #if PTTYPE == 64
        if (!is_long_mode(vcpu)) {
                walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3];
                root = *walker->ptep;
+               walker->pte = root;
                if (!(root & PT_PRESENT_MASK))
                        goto not_present;
                --walker->level;
@@ -96,10 +104,11 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
                 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);
+       walker->page = pfn_to_page(hpa >> PAGE_SHIFT);
+       walker->table = kmap_atomic(walker->page, KM_USER0);
 
        ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
-              (vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) == 0);
+              (vcpu->cr3 & CR3_NONPAE_RESERVED_BITS) == 0);
 
        walker->inherited_ar = PT_USER_MASK | PT_WRITABLE_MASK;
 
@@ -108,6 +117,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
                hpa_t paddr;
 
                ptep = &walker->table[index];
+               walker->index = index;
                ASSERT(((unsigned long)walker->table & PAGE_MASK) ==
                       ((unsigned long)ptep & PAGE_MASK));
 
@@ -148,16 +158,20 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
 
                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);
+               paddr = safe_gpa_to_hpa(vcpu, table_gfn << PAGE_SHIFT);
+               walker->page = pfn_to_page(paddr >> PAGE_SHIFT);
+               walker->table = kmap_atomic(walker->page, 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;
+       walker->pte = *ptep;
+       if (walker->page)
+               walker->ptep = NULL;
+       if (walker->table)
+               kunmap_atomic(walker->table, KM_USER0);
        pgprintk("%s: pte %llx\n", __FUNCTION__, (u64)*ptep);
        return 1;
 
@@ -175,13 +189,9 @@ err:
                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);
+       return 0;
 }
 
 static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
@@ -193,7 +203,7 @@ static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
 static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
                                  u64 *shadow_pte,
                                  gpa_t gaddr,
-                                 pt_element_t *gpte,
+                                 pt_element_t gpte,
                                  u64 access_bits,
                                  int user_fault,
                                  int write_fault,
@@ -202,23 +212,39 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
                                  gfn_t gfn)
 {
        hpa_t paddr;
-       int dirty = *gpte & PT_DIRTY_MASK;
-       u64 spte = *shadow_pte;
-       int was_rmapped = is_rmap_pte(spte);
+       int dirty = gpte & PT_DIRTY_MASK;
+       u64 spte;
+       int was_rmapped = is_rmap_pte(*shadow_pte);
 
        pgprintk("%s: spte %llx gpte %llx access %llx write_fault %d"
                 " user_fault %d gfn %lx\n",
-                __FUNCTION__, spte, (u64)*gpte, access_bits,
+                __FUNCTION__, *shadow_pte, (u64)gpte, access_bits,
                 write_fault, user_fault, gfn);
 
        if (write_fault && !dirty) {
-               *gpte |= PT_DIRTY_MASK;
+               pt_element_t *guest_ent, *tmp = NULL;
+
+               if (walker->ptep)
+                       guest_ent = walker->ptep;
+               else {
+                       tmp = kmap_atomic(walker->page, KM_USER0);
+                       guest_ent = &tmp[walker->index];
+               }
+
+               *guest_ent |= PT_DIRTY_MASK;
+               if (!walker->ptep)
+                       kunmap_atomic(tmp, KM_USER0);
                dirty = 1;
                FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
        }
 
-       spte |= PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK;
-       spte |= *gpte & PT64_NX_MASK;
+       /*
+        * We don't set the accessed bit, since we sometimes want to see
+        * whether the guest actually used the pte (in order to detect
+        * demand paging).
+        */
+       spte = PT_PRESENT_MASK | PT_DIRTY_MASK;
+       spte |= gpte & PT64_NX_MASK;
        if (!dirty)
                access_bits &= ~PT_WRITABLE_MASK;
 
@@ -229,10 +255,8 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
                spte |= PT_USER_MASK;
 
        if (is_error_hpa(paddr)) {
-               spte |= gaddr;
-               spte |= PT_SHADOW_IO_MARK;
-               spte &= ~PT_PRESENT_MASK;
-               set_shadow_pte(shadow_pte, spte);
+               set_shadow_pte(shadow_pte,
+                              shadow_trap_nonpresent_pte | PT_SHADOW_IO_MARK);
                return;
        }
 
@@ -255,7 +279,7 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
                        access_bits &= ~PT_WRITABLE_MASK;
                        if (is_writeble_pte(spte)) {
                                spte &= ~PT_WRITABLE_MASK;
-                               kvm_arch_ops->tlb_flush(vcpu);
+                               kvm_x86_ops->tlb_flush(vcpu);
                        }
                        if (write_fault)
                                *ptwrite = 1;
@@ -267,50 +291,57 @@ unshadowed:
        if (access_bits & PT_WRITABLE_MASK)
                mark_page_dirty(vcpu->kvm, gaddr >> PAGE_SHIFT);
 
+       pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte);
        set_shadow_pte(shadow_pte, spte);
        page_header_update_slot(vcpu->kvm, shadow_pte, gaddr);
        if (!was_rmapped)
                rmap_add(vcpu, shadow_pte);
+       if (!ptwrite || !*ptwrite)
+               vcpu->last_pte_updated = shadow_pte;
 }
 
-static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t *gpte,
+static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t gpte,
                           u64 *shadow_pte, u64 access_bits,
                           int user_fault, int write_fault, int *ptwrite,
                           struct guest_walker *walker, gfn_t gfn)
 {
-       access_bits &= *gpte;
-       FNAME(set_pte_common)(vcpu, shadow_pte, *gpte & PT_BASE_ADDR_MASK,
+       access_bits &= gpte;
+       FNAME(set_pte_common)(vcpu, shadow_pte, gpte & PT_BASE_ADDR_MASK,
                              gpte, access_bits, user_fault, write_fault,
                              ptwrite, walker, gfn);
 }
 
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
-                             u64 *spte, const void *pte, int bytes)
+                             u64 *spte, const void *pte, int bytes,
+                             int offset_in_pte)
 {
        pt_element_t gpte;
 
-       if (bytes < sizeof(pt_element_t))
-               return;
        gpte = *(const pt_element_t *)pte;
-       if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK))
+       if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
+               if (!offset_in_pte && !is_present_pte(gpte))
+                       set_shadow_pte(spte, shadow_notrap_nonpresent_pte);
+               return;
+       }
+       if (bytes < sizeof(pt_element_t))
                return;
        pgprintk("%s: gpte %llx spte %p\n", __FUNCTION__, (u64)gpte, spte);
-       FNAME(set_pte)(vcpu, &gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK, 0,
+       FNAME(set_pte)(vcpu, gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK, 0,
                       0, NULL, NULL,
                       (gpte & PT_BASE_ADDR_MASK) >> PAGE_SHIFT);
 }
 
-static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t *gpde,
+static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t gpde,
                           u64 *shadow_pte, u64 access_bits,
                           int user_fault, int write_fault, int *ptwrite,
                           struct guest_walker *walker, gfn_t gfn)
 {
        gpa_t gaddr;
 
-       access_bits &= *gpde;
+       access_bits &= gpde;
        gaddr = (gpa_t)gfn << PAGE_SHIFT;
        if (PTTYPE == 32 && is_cpuid_PSE36())
-               gaddr |= (*gpde & PT32_DIR_PSE36_MASK) <<
+               gaddr |= (gpde & PT32_DIR_PSE36_MASK) <<
                        (32 - PT32_DIR_PSE36_SHIFT);
        FNAME(set_pte_common)(vcpu, shadow_pte, gaddr,
                              gpde, access_bits, user_fault, write_fault,
@@ -328,9 +359,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
        int level;
        u64 *shadow_ent;
        u64 *prev_shadow_ent = NULL;
-       pt_element_t *guest_ent = walker->ptep;
 
-       if (!is_present_pte(*guest_ent))
+       if (!is_present_pte(walker->pte))
                return NULL;
 
        shadow_addr = vcpu->mmu.root_hpa;
@@ -350,7 +380,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
                unsigned hugepage_access = 0;
 
                shadow_ent = ((u64 *)__va(shadow_addr)) + index;
-               if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {
+               if (is_shadow_present_pte(*shadow_ent)) {
                        if (level == PT_PAGE_TABLE_LEVEL)
                                break;
                        shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
@@ -364,10 +394,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
                if (level - 1 == PT_PAGE_TABLE_LEVEL
                    && walker->level == PT_DIRECTORY_LEVEL) {
                        metaphysical = 1;
-                       hugepage_access = *guest_ent;
+                       hugepage_access = walker->pte;
                        hugepage_access &= PT_USER_MASK | PT_WRITABLE_MASK;
+                       if (walker->pte & PT64_NX_MASK)
+                               hugepage_access |= (1 << 2);
                        hugepage_access >>= PT_WRITABLE_SHIFT;
-                       table_gfn = (*guest_ent & PT_BASE_ADDR_MASK)
+                       table_gfn = (walker->pte & PT_BASE_ADDR_MASK)
                                >> PAGE_SHIFT;
                } else {
                        metaphysical = 0;
@@ -384,12 +416,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
        }
 
        if (walker->level == PT_DIRECTORY_LEVEL) {
-               FNAME(set_pde)(vcpu, guest_ent, shadow_ent,
+               FNAME(set_pde)(vcpu, walker->pte, shadow_ent,
                               walker->inherited_ar, user_fault, write_fault,
                               ptwrite, walker, walker->gfn);
        } else {
                ASSERT(walker->level == PT_PAGE_TABLE_LEVEL);
-               FNAME(set_pte)(vcpu, guest_ent, shadow_ent,
+               FNAME(set_pte)(vcpu, walker->pte, shadow_ent,
                               walker->inherited_ar, user_fault, write_fault,
                               ptwrite, walker, walker->gfn);
        }
@@ -440,7 +472,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
        if (!r) {
                pgprintk("%s: guest page fault\n", __FUNCTION__);
                inject_page_fault(vcpu, addr, walker.error_code);
-               FNAME(release_walker)(&walker);
                vcpu->last_pt_write_count = 0; /* reset fork detector */
                return 0;
        }
@@ -450,8 +481,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
        pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
                 shadow_pte, *shadow_pte, write_pt);
 
-       FNAME(release_walker)(&walker);
-
        if (!write_pt)
                vcpu->last_pt_write_count = 0; /* reset fork detector */
 
@@ -480,10 +509,29 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
                gpa |= vaddr & ~PAGE_MASK;
        }
 
-       FNAME(release_walker)(&walker);
        return gpa;
 }
 
+static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
+                                struct kvm_mmu_page *sp)
+{
+       int i;
+       pt_element_t *gpt;
+
+       if (sp->role.metaphysical || PTTYPE == 32) {
+               nonpaging_prefetch_page(vcpu, sp);
+               return;
+       }
+
+       gpt = kmap_atomic(gfn_to_page(vcpu->kvm, sp->gfn), KM_USER0);
+       for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
+               if (is_present_pte(gpt[i]))
+                       sp->spt[i] = shadow_trap_nonpresent_pte;
+               else
+                       sp->spt[i] = shadow_notrap_nonpresent_pte;
+       kunmap_atomic(gpt, KM_USER0);
+}
+
 #undef pt_element_t
 #undef guest_walker
 #undef FNAME
@@ -492,4 +540,5 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
 #undef SHADOW_PT_INDEX
 #undef PT_LEVEL_MASK
 #undef PT_DIR_BASE_ADDR_MASK
+#undef PT_LEVEL_BITS
 #undef PT_MAX_FULL_LEVELS