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Diffstat (limited to 'arch/x86/kvm/mmu.h')
| -rw-r--r-- | arch/x86/kvm/mmu.h | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h new file mode 100644 index 000000000..59804be91 --- /dev/null +++ b/arch/x86/kvm/mmu.h @@ -0,0 +1,305 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __KVM_X86_MMU_H +#define __KVM_X86_MMU_H + +#include <linux/kvm_host.h> +#include "kvm_cache_regs.h" +#include "cpuid.h" + +extern bool __read_mostly enable_mmio_caching; + +#define PT_WRITABLE_SHIFT 1 +#define PT_USER_SHIFT 2 + +#define PT_PRESENT_MASK (1ULL << 0) +#define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT) +#define PT_USER_MASK (1ULL << PT_USER_SHIFT) +#define PT_PWT_MASK (1ULL << 3) +#define PT_PCD_MASK (1ULL << 4) +#define PT_ACCESSED_SHIFT 5 +#define PT_ACCESSED_MASK (1ULL << PT_ACCESSED_SHIFT) +#define PT_DIRTY_SHIFT 6 +#define PT_DIRTY_MASK (1ULL << PT_DIRTY_SHIFT) +#define PT_PAGE_SIZE_SHIFT 7 +#define PT_PAGE_SIZE_MASK (1ULL << PT_PAGE_SIZE_SHIFT) +#define PT_PAT_MASK (1ULL << 7) +#define PT_GLOBAL_MASK (1ULL << 8) +#define PT64_NX_SHIFT 63 +#define PT64_NX_MASK (1ULL << PT64_NX_SHIFT) + +#define PT_PAT_SHIFT 7 +#define PT_DIR_PAT_SHIFT 12 +#define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT) + +#define PT64_ROOT_5LEVEL 5 +#define PT64_ROOT_4LEVEL 4 +#define PT32_ROOT_LEVEL 2 +#define PT32E_ROOT_LEVEL 3 + +#define KVM_MMU_CR4_ROLE_BITS (X86_CR4_PSE | X86_CR4_PAE | X86_CR4_LA57 | \ + 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) +{ + BUILD_BUG_ON(__builtin_constant_p(e) && __builtin_constant_p(s) && e < s); + + if (__builtin_constant_p(e)) + BUILD_BUG_ON(e > 63); + else + e &= 63; + + if (e < s) + return 0; + + 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, + 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); +void __kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu, + struct kvm_mmu *mmu); + +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)) + return 0; + + return kvm_mmu_load(vcpu); +} + +static inline unsigned long kvm_get_pcid(struct kvm_vcpu *vcpu, gpa_t cr3) +{ + BUILD_BUG_ON((X86_CR3_PCID_MASK & PAGE_MASK) != 0); + + return kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE) + ? cr3 & X86_CR3_PCID_MASK + : 0; +} + +static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu) +{ + return kvm_get_pcid(vcpu, kvm_read_cr3(vcpu)); +} + +static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) +{ + 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->root_role.level); +} + +static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu, + struct kvm_mmu *mmu) +{ + /* + * When EPT is enabled, KVM may passthrough CR0.WP to the guest, i.e. + * @mmu's snapshot of CR0.WP and thus all related paging metadata may + * be stale. Refresh CR0.WP and the metadata on-demand when checking + * for permission faults. Exempt nested MMUs, i.e. MMUs for shadowing + * nEPT and nNPT, as CR0.WP is ignored in both cases. Note, KVM does + * need to refresh nested_mmu, a.k.a. the walker used to translate L2 + * GVAs to GPAs, as that "MMU" needs to honor L2's CR0.WP. + */ + if (!tdp_enabled || mmu == &vcpu->arch.guest_mmu) + return; + + __kvm_mmu_refresh_passthrough_bits(vcpu, mmu); +} + +/* + * Check if a given access (described through the I/D, W/R and U/S bits of a + * page fault error code pfec) causes a permission fault with the given PTE + * access rights (in ACC_* format). + * + * Return zero if the access does not fault; return the page fault error code + * if the access faults. + */ +static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, + unsigned pte_access, unsigned pte_pkey, + u64 access) +{ + /* strip nested paging fault error codes */ + unsigned int pfec = access; + unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu); + + /* + * For explicit supervisor accesses, SMAP is disabled if EFLAGS.AC = 1. + * For implicit supervisor accesses, SMAP cannot be overridden. + * + * 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. + * + * 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. + */ + 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; + u32 errcode = PFERR_PRESENT_MASK; + bool fault; + + kvm_mmu_refresh_passthrough_bits(vcpu, mmu); + + fault = (mmu->permissions[index] >> pte_access) & 1; + + WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK)); + if (unlikely(mmu->pkru_mask)) { + u32 pkru_bits, offset; + + /* + * PKRU defines 32 bits, there are 16 domains and 2 + * attribute bits per domain in pkru. pte_pkey is the + * index of the protection domain, so pte_pkey * 2 is + * is the index of the first bit for the domain. + */ + pkru_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3; + + /* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */ + offset = (pfec & ~1) + + ((pte_access & PT_USER_MASK) << (PFERR_RSVD_BIT - PT_USER_SHIFT)); + + pkru_bits &= mmu->pkru_mask >> offset; + errcode |= -pkru_bits & PFERR_PK_MASK; + fault |= (pkru_bits != 0); + } + + return -(u32)fault & errcode; +} + +void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end); + +int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu); + +int kvm_mmu_post_init_vm(struct kvm *kvm); +void kvm_mmu_pre_destroy_vm(struct kvm *kvm); + +static inline bool kvm_shadow_root_allocated(struct kvm *kvm) +{ + /* + * Read shadow_root_allocated before related pointers. Hence, threads + * reading shadow_root_allocated in any lock context are guaranteed to + * see the pointers. Pairs with smp_store_release in + * mmu_first_shadow_root_alloc. + */ + return smp_load_acquire(&kvm->arch.shadow_root_allocated); +} + +#ifdef CONFIG_X86_64 +static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return kvm->arch.tdp_mmu_enabled; } +#else +static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return false; } +#endif + +static inline bool kvm_memslots_have_rmaps(struct kvm *kvm) +{ + return !is_tdp_mmu_enabled(kvm) || kvm_shadow_root_allocated(kvm); +} + +static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level) +{ + /* KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K) must be 0. */ + return (gfn >> KVM_HPAGE_GFN_SHIFT(level)) - + (base_gfn >> KVM_HPAGE_GFN_SHIFT(level)); +} + +static inline unsigned long +__kvm_mmu_slot_lpages(struct kvm_memory_slot *slot, unsigned long npages, + int level) +{ + return gfn_to_index(slot->base_gfn + npages - 1, + slot->base_gfn, level) + 1; +} + +static inline unsigned long +kvm_mmu_slot_lpages(struct kvm_memory_slot *slot, int level) +{ + return __kvm_mmu_slot_lpages(slot, slot->npages, level); +} + +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 |