linux/linux-5.18.11/arch/x86/kvm/mmu.h

357 lines
10 KiB
C

/* 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"
#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)
#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 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
#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;
}
void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_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);
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->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);
}
/*
* 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;
bool fault = (mmu->permissions[index] >> pte_access) & 1;
u32 errcode = PFERR_PRESENT_MASK;
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