diff options
| -rw-r--r-- | arch/x86/kvm/mmu.c | 12 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.h | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 24 |
3 files changed, 26 insertions, 13 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index aa0b469ee07d..54c9cb4fdfa4 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3408,6 +3408,18 @@ static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level) return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0; } +static inline void protect_clean_gpte(unsigned *access, unsigned gpte) +{ + unsigned mask; + + BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK); + + mask = (unsigned)~ACC_WRITE_MASK; + /* Allow write access to dirty gptes */ + mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK; + *access &= mask; +} + static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access, int *nr_present) { diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index e374db9af021..2832081e9b2e 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -18,7 +18,8 @@ #define PT_PCD_MASK (1ULL << 4) #define PT_ACCESSED_SHIFT 5 #define PT_ACCESSED_MASK (1ULL << PT_ACCESSED_SHIFT) -#define PT_DIRTY_MASK (1ULL << 6) +#define PT_DIRTY_SHIFT 6 +#define PT_DIRTY_MASK (1ULL << PT_DIRTY_SHIFT) #define PT_PAGE_SIZE_MASK (1ULL << 7) #define PT_PAT_MASK (1ULL << 7) #define PT_GLOBAL_MASK (1ULL << 8) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index bf8c42bf50fe..bf7b4ffafab8 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -101,14 +101,11 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, return (ret != orig_pte); } -static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte, - bool last) +static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte) { unsigned access; access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK; - if (last && !is_dirty_gpte(gpte)) - access &= ~ACC_WRITE_MASK; #if PTTYPE == 64 if (vcpu->arch.mmu.nx) @@ -222,8 +219,7 @@ retry_walk: last_gpte = FNAME(is_last_gpte)(walker, vcpu, mmu, pte); if (last_gpte) { - pte_access = pt_access & - FNAME(gpte_access)(vcpu, pte, true); + pte_access = pt_access & FNAME(gpte_access)(vcpu, pte); /* check if the kernel is fetching from user page */ if (unlikely(pte_access & PT_USER_MASK) && kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)) @@ -274,7 +270,7 @@ retry_walk: break; } - pt_access &= FNAME(gpte_access)(vcpu, pte, false); + pt_access &= FNAME(gpte_access)(vcpu, pte); --walker->level; } @@ -283,7 +279,9 @@ retry_walk: goto error; } - if (write_fault && unlikely(!is_dirty_gpte(pte))) { + if (!write_fault) + protect_clean_gpte(&pte_access, pte); + else if (unlikely(!is_dirty_gpte(pte))) { int ret; trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte)); @@ -368,7 +366,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, return; pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte); - pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, true); + pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte); + protect_clean_gpte(&pte_access, gpte); pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte)); if (mmu_invalid_pfn(pfn)) return; @@ -441,8 +440,8 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw, if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte)) continue; - pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, - true); + pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte); + protect_clean_gpte(&pte_access, gpte); gfn = gpte_to_gfn(gpte); pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn, pte_access & ACC_WRITE_MASK); @@ -794,7 +793,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) gfn = gpte_to_gfn(gpte); pte_access = sp->role.access; - pte_access &= FNAME(gpte_access)(vcpu, gpte, true); + pte_access &= FNAME(gpte_access)(vcpu, gpte); + protect_clean_gpte(&pte_access, gpte); if (sync_mmio_spte(&sp->spt[i], gfn, pte_access, &nr_present)) continue; |