diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/mmu.h | 231 |
1 files changed, 79 insertions, 152 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 9ae6168d381e..6bdaacb6faa0 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -6,10 +6,7 @@ #include "kvm_cache_regs.h" #include "cpuid.h" -#define PT64_PT_BITS 9 -#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS) -#define PT32_PT_BITS 10 -#define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS) +extern bool __read_mostly enable_mmio_caching; #define PT_WRITABLE_SHIFT 1 #define PT_USER_SHIFT 2 @@ -34,11 +31,6 @@ #define PT_DIR_PAT_SHIFT 12 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT) -#define PT32_DIR_PSE36_SIZE 4 -#define PT32_DIR_PSE36_SHIFT 13 -#define PT32_DIR_PSE36_MASK \ - (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT) - #define PT64_ROOT_5LEVEL 5 #define PT64_ROOT_4LEVEL 4 #define PT32_ROOT_LEVEL 2 @@ -48,6 +40,7 @@ X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE) #define KVM_MMU_CR0_ROLE_BITS (X86_CR0_PG | X86_CR0_WP) +#define KVM_MMU_EFER_ROLE_BITS (EFER_LME | EFER_NX) static __always_inline u64 rsvd_bits(int s, int e) { @@ -64,26 +57,72 @@ static __always_inline u64 rsvd_bits(int s, int e) return ((2ULL << (e - s)) - 1) << s; } +/* + * The number of non-reserved physical address bits irrespective of features + * that repurpose legal bits, e.g. MKTME. + */ +extern u8 __read_mostly shadow_phys_bits; + +static inline gfn_t kvm_mmu_max_gfn(void) +{ + /* + * Note that this uses the host MAXPHYADDR, not the guest's. + * EPT/NPT cannot support GPAs that would exceed host.MAXPHYADDR; + * assuming KVM is running on bare metal, guest accesses beyond + * host.MAXPHYADDR will hit a #PF(RSVD) and never cause a vmexit + * (either EPT Violation/Misconfig or #NPF), and so KVM will never + * install a SPTE for such addresses. If KVM is running as a VM + * itself, on the other hand, it might see a MAXPHYADDR that is less + * than hardware's real MAXPHYADDR. Using the host MAXPHYADDR + * disallows such SPTEs entirely and simplifies the TDP MMU. + */ + int max_gpa_bits = likely(tdp_enabled) ? shadow_phys_bits : 52; + + return (1ULL << (max_gpa_bits - PAGE_SHIFT)) - 1; +} + +static inline u8 kvm_get_shadow_phys_bits(void) +{ + /* + * boot_cpu_data.x86_phys_bits is reduced when MKTME or SME are detected + * in CPU detection code, but the processor treats those reduced bits as + * 'keyID' thus they are not reserved bits. Therefore KVM needs to look at + * the physical address bits reported by CPUID. + */ + if (likely(boot_cpu_data.extended_cpuid_level >= 0x80000008)) + return cpuid_eax(0x80000008) & 0xff; + + /* + * Quite weird to have VMX or SVM but not MAXPHYADDR; probably a VM with + * custom CPUID. Proceed with whatever the kernel found since these features + * aren't virtualizable (SME/SEV also require CPUIDs higher than 0x80000008). + */ + return boot_cpu_data.x86_phys_bits; +} + void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask); +void kvm_mmu_set_me_spte_mask(u64 me_value, u64 me_mask); void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only); void kvm_init_mmu(struct kvm_vcpu *vcpu); void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0, unsigned long cr4, u64 efer, gpa_t nested_cr3); void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, - bool accessed_dirty, gpa_t new_eptp); + int huge_page_level, bool accessed_dirty, + gpa_t new_eptp); bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu); int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, u64 fault_address, char *insn, int insn_len); int kvm_mmu_load(struct kvm_vcpu *vcpu); void kvm_mmu_unload(struct kvm_vcpu *vcpu); +void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu); void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu); void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu); static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu) { - if (likely(vcpu->arch.mmu->root_hpa != INVALID_PAGE)) + if (likely(vcpu->arch.mmu->root.hpa != INVALID_PAGE)) return 0; return kvm_mmu_load(vcpu); @@ -105,138 +144,13 @@ static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu) static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) { - u64 root_hpa = vcpu->arch.mmu->root_hpa; + u64 root_hpa = vcpu->arch.mmu->root.hpa; if (!VALID_PAGE(root_hpa)) return; static_call(kvm_x86_load_mmu_pgd)(vcpu, root_hpa, - vcpu->arch.mmu->shadow_root_level); -} - -struct kvm_page_fault { - /* arguments to kvm_mmu_do_page_fault. */ - const gpa_t addr; - const u32 error_code; - const bool prefetch; - - /* Derived from error_code. */ - const bool exec; - const bool write; - const bool present; - const bool rsvd; - const bool user; - - /* Derived from mmu and global state. */ - const bool is_tdp; - const bool nx_huge_page_workaround_enabled; - - /* - * Whether a >4KB mapping can be created or is forbidden due to NX - * hugepages. - */ - bool huge_page_disallowed; - - /* - * Maximum page size that can be created for this fault; input to - * FNAME(fetch), __direct_map and kvm_tdp_mmu_map. - */ - u8 max_level; - - /* - * Page size that can be created based on the max_level and the - * page size used by the host mapping. - */ - u8 req_level; - - /* - * Page size that will be created based on the req_level and - * huge_page_disallowed. - */ - u8 goal_level; - - /* Shifted addr, or result of guest page table walk if addr is a gva. */ - gfn_t gfn; - - /* The memslot containing gfn. May be NULL. */ - struct kvm_memory_slot *slot; - - /* Outputs of kvm_faultin_pfn. */ - kvm_pfn_t pfn; - hva_t hva; - bool map_writable; -}; - -int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); - -extern int nx_huge_pages; -static inline bool is_nx_huge_page_enabled(void) -{ - return READ_ONCE(nx_huge_pages); -} - -static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, - u32 err, bool prefetch) -{ - struct kvm_page_fault fault = { - .addr = cr2_or_gpa, - .error_code = err, - .exec = err & PFERR_FETCH_MASK, - .write = err & PFERR_WRITE_MASK, - .present = err & PFERR_PRESENT_MASK, - .rsvd = err & PFERR_RSVD_MASK, - .user = err & PFERR_USER_MASK, - .prefetch = prefetch, - .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault), - .nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(), - - .max_level = KVM_MAX_HUGEPAGE_LEVEL, - .req_level = PG_LEVEL_4K, - .goal_level = PG_LEVEL_4K, - }; -#ifdef CONFIG_RETPOLINE - if (fault.is_tdp) - return kvm_tdp_page_fault(vcpu, &fault); -#endif - return vcpu->arch.mmu->page_fault(vcpu, &fault); -} - -/* - * Currently, we have two sorts of write-protection, a) the first one - * write-protects guest page to sync the guest modification, b) another one is - * used to sync dirty bitmap when we do KVM_GET_DIRTY_LOG. The differences - * between these two sorts are: - * 1) the first case clears MMU-writable bit. - * 2) the first case requires flushing tlb immediately avoiding corrupting - * shadow page table between all vcpus so it should be in the protection of - * mmu-lock. And the another case does not need to flush tlb until returning - * the dirty bitmap to userspace since it only write-protects the page - * logged in the bitmap, that means the page in the dirty bitmap is not - * missed, so it can flush tlb out of mmu-lock. - * - * So, there is the problem: the first case can meet the corrupted tlb caused - * by another case which write-protects pages but without flush tlb - * immediately. In order to making the first case be aware this problem we let - * it flush tlb if we try to write-protect a spte whose MMU-writable bit - * is set, it works since another case never touches MMU-writable bit. - * - * Anyway, whenever a spte is updated (only permission and status bits are - * changed) we need to check whether the spte with MMU-writable becomes - * readonly, if that happens, we need to flush tlb. Fortunately, - * mmu_spte_update() has already handled it perfectly. - * - * The rules to use MMU-writable and PT_WRITABLE_MASK: - * - if we want to see if it has writable tlb entry or if the spte can be - * writable on the mmu mapping, check MMU-writable, this is the most - * case, otherwise - * - if we fix page fault on the spte or do write-protection by dirty logging, - * check PT_WRITABLE_MASK. - * - * TODO: introduce APIs to split these two cases. - */ -static inline bool is_writable_pte(unsigned long pte) -{ - return pte & PT_WRITABLE_MASK; + vcpu->arch.mmu->root_role.level); } /* @@ -249,27 +163,27 @@ static inline bool is_writable_pte(unsigned long pte) */ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned pte_access, unsigned pte_pkey, - unsigned pfec) + u64 access) { - int cpl = static_call(kvm_x86_get_cpl)(vcpu); + /* strip nested paging fault error codes */ + unsigned int pfec = access; unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu); /* - * If CPL < 3, SMAP prevention are disabled if EFLAGS.AC = 1. + * For explicit supervisor accesses, SMAP is disabled if EFLAGS.AC = 1. + * For implicit supervisor accesses, SMAP cannot be overridden. * - * If CPL = 3, SMAP applies to all supervisor-mode data accesses - * (these are implicit supervisor accesses) regardless of the value - * of EFLAGS.AC. + * SMAP works on supervisor accesses only, and not_smap can + * be set or not set when user access with neither has any bearing + * on the result. * - * This computes (cpl < 3) && (rflags & X86_EFLAGS_AC), leaving - * the result in X86_EFLAGS_AC. We then insert it in place of - * the PFERR_RSVD_MASK bit; this bit will always be zero in pfec, - * but it will be one in index if SMAP checks are being overridden. - * It is important to keep this branchless. + * We put the SMAP checking bit in place of the PFERR_RSVD_MASK bit; + * this bit will always be zero in pfec, but it will be one in index + * if SMAP checks are being disabled. */ - unsigned long smap = (cpl - 3) & (rflags & X86_EFLAGS_AC); - int index = (pfec >> 1) + - (smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1)); + u64 implicit_access = access & PFERR_IMPLICIT_ACCESS; + bool not_smap = ((rflags & X86_EFLAGS_AC) | implicit_access) == X86_EFLAGS_AC; + int index = (pfec + (not_smap << PFERR_RSVD_BIT)) >> 1; bool fault = (mmu->permissions[index] >> pte_access) & 1; u32 errcode = PFERR_PRESENT_MASK; @@ -351,4 +265,17 @@ static inline void kvm_update_page_stats(struct kvm *kvm, int level, int count) { atomic64_add(count, &kvm->stat.pages[level - 1]); } + +gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access, + struct x86_exception *exception); + +static inline gpa_t kvm_translate_gpa(struct kvm_vcpu *vcpu, + struct kvm_mmu *mmu, + gpa_t gpa, u64 access, + struct x86_exception *exception) +{ + if (mmu != &vcpu->arch.nested_mmu) + return gpa; + return translate_nested_gpa(vcpu, gpa, access, exception); +} #endif |