diff options
| -rw-r--r-- | arch/x86/kvm/mmu.c | 103 |
1 files changed, 69 insertions, 34 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 1d4a2d9cc718..982718fe12a7 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -299,12 +299,30 @@ static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask) return (old_spte & bit_mask) && !(new_spte & bit_mask); } -static void update_spte(u64 *sptep, u64 new_spte) +/* Rules for using mmu_spte_set: + * Set the sptep from nonpresent to present. + * Note: the sptep being assigned *must* be either not present + * or in a state where the hardware will not attempt to update + * the spte. + */ +static void mmu_spte_set(u64 *sptep, u64 new_spte) +{ + WARN_ON(is_shadow_present_pte(*sptep)); + __set_spte(sptep, new_spte); +} + +/* Rules for using mmu_spte_update: + * Update the state bits, it means the mapped pfn is not changged. + */ +static void mmu_spte_update(u64 *sptep, u64 new_spte) { u64 mask, old_spte = *sptep; WARN_ON(!is_rmap_spte(new_spte)); + if (!is_shadow_present_pte(old_spte)) + return mmu_spte_set(sptep, new_spte); + new_spte |= old_spte & shadow_dirty_mask; mask = shadow_accessed_mask; @@ -325,6 +343,42 @@ static void update_spte(u64 *sptep, u64 new_spte) kvm_set_pfn_dirty(spte_to_pfn(old_spte)); } +/* + * Rules for using mmu_spte_clear_track_bits: + * It sets the sptep from present to nonpresent, and track the + * state bits, it is used to clear the last level sptep. + */ +static int mmu_spte_clear_track_bits(u64 *sptep) +{ + pfn_t pfn; + u64 old_spte = *sptep; + + if (!spte_has_volatile_bits(old_spte)) + __set_spte(sptep, 0ull); + else + old_spte = __xchg_spte(sptep, 0ull); + + if (!is_rmap_spte(old_spte)) + return 0; + + pfn = spte_to_pfn(old_spte); + if (!shadow_accessed_mask || old_spte & shadow_accessed_mask) + kvm_set_pfn_accessed(pfn); + if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask)) + kvm_set_pfn_dirty(pfn); + return 1; +} + +/* + * Rules for using mmu_spte_clear_no_track: + * Directly clear spte without caring the state bits of sptep, + * it is used to set the upper level spte. + */ +static void mmu_spte_clear_no_track(u64 *sptep) +{ + __set_spte(sptep, 0ull); +} + static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, struct kmem_cache *base_cache, int min) { @@ -746,30 +800,9 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) pte_list_remove(spte, rmapp); } -static int set_spte_track_bits(u64 *sptep, u64 new_spte) -{ - pfn_t pfn; - u64 old_spte = *sptep; - - if (!spte_has_volatile_bits(old_spte)) - __set_spte(sptep, new_spte); - else - old_spte = __xchg_spte(sptep, new_spte); - - if (!is_rmap_spte(old_spte)) - return 0; - - pfn = spte_to_pfn(old_spte); - if (!shadow_accessed_mask || old_spte & shadow_accessed_mask) - kvm_set_pfn_accessed(pfn); - if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask)) - kvm_set_pfn_dirty(pfn); - return 1; -} - static void drop_spte(struct kvm *kvm, u64 *sptep) { - if (set_spte_track_bits(sptep, 0ull)) + if (mmu_spte_clear_track_bits(sptep)) rmap_remove(kvm, sptep); } @@ -787,7 +820,7 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn) BUG_ON(!(*spte & PT_PRESENT_MASK)); rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); if (is_writable_pte(*spte)) { - update_spte(spte, *spte & ~PT_WRITABLE_MASK); + mmu_spte_update(spte, *spte & ~PT_WRITABLE_MASK); write_protected = 1; } spte = rmap_next(kvm, rmapp, spte); @@ -856,7 +889,8 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, new_spte &= ~PT_WRITABLE_MASK; new_spte &= ~SPTE_HOST_WRITEABLE; new_spte &= ~shadow_accessed_mask; - set_spte_track_bits(spte, new_spte); + mmu_spte_clear_track_bits(spte); + mmu_spte_set(spte, new_spte); spte = rmap_next(kvm, rmapp, spte); } } @@ -1077,7 +1111,7 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, u64 *parent_pte) { mmu_page_remove_parent_pte(sp, parent_pte); - __set_spte(parent_pte, 0ull); + mmu_spte_clear_no_track(parent_pte); } static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, @@ -1525,7 +1559,7 @@ static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp) spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; - __set_spte(sptep, spte); + mmu_spte_set(sptep, spte); } static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) @@ -1992,7 +2026,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, mark_page_dirty(vcpu->kvm, gfn); set_pte: - update_spte(sptep, spte); + mmu_spte_update(sptep, spte); /* * If we overwrite a writable spte with a read-only one we * should flush remote TLBs. Otherwise rmap_write_protect @@ -2198,11 +2232,11 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, return -ENOMEM; } - __set_spte(iterator.sptep, - __pa(sp->spt) - | PT_PRESENT_MASK | PT_WRITABLE_MASK - | shadow_user_mask | shadow_x_mask - | shadow_accessed_mask); + mmu_spte_set(iterator.sptep, + __pa(sp->spt) + | PT_PRESENT_MASK | PT_WRITABLE_MASK + | shadow_user_mask | shadow_x_mask + | shadow_accessed_mask); } } return emulate; @@ -3439,7 +3473,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) /* avoid RMW */ if (is_writable_pte(pt[i])) - update_spte(&pt[i], pt[i] & ~PT_WRITABLE_MASK); + mmu_spte_update(&pt[i], + pt[i] & ~PT_WRITABLE_MASK); } } kvm_flush_remote_tlbs(kvm); |