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Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
-rw-r--r--arch/x86/kvm/mmu/mmu.c60
1 files changed, 8 insertions, 52 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 126fa9aec64c..e418ef3ecfcb 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5361,19 +5361,6 @@ void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu)
__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.guest_mmu);
}
-static bool need_remote_flush(u64 old, u64 new)
-{
- if (!is_shadow_present_pte(old))
- return false;
- if (!is_shadow_present_pte(new))
- return true;
- if ((old ^ new) & SPTE_BASE_ADDR_MASK)
- return true;
- old ^= shadow_nx_mask;
- new ^= shadow_nx_mask;
- return (old & ~new & SPTE_PERM_MASK) != 0;
-}
-
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
int *bytes)
{
@@ -5519,7 +5506,7 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
mmu_page_zap_pte(vcpu->kvm, sp, spte, NULL);
if (gentry && sp->role.level != PG_LEVEL_4K)
++vcpu->kvm->stat.mmu_pde_zapped;
- if (need_remote_flush(entry, *spte))
+ if (is_shadow_present_pte(entry))
flush = true;
++spte;
}
@@ -6085,47 +6072,18 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
const struct kvm_memory_slot *memslot,
int start_level)
{
- bool flush = false;
-
if (kvm_memslots_have_rmaps(kvm)) {
write_lock(&kvm->mmu_lock);
- flush = slot_handle_level(kvm, memslot, slot_rmap_write_protect,
- start_level, KVM_MAX_HUGEPAGE_LEVEL,
- false);
+ slot_handle_level(kvm, memslot, slot_rmap_write_protect,
+ start_level, KVM_MAX_HUGEPAGE_LEVEL, false);
write_unlock(&kvm->mmu_lock);
}
if (is_tdp_mmu_enabled(kvm)) {
read_lock(&kvm->mmu_lock);
- flush |= kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level);
+ kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level);
read_unlock(&kvm->mmu_lock);
}
-
- /*
- * Flush TLBs if any SPTEs had to be write-protected to ensure that
- * guest writes are reflected in the dirty bitmap before the memslot
- * update completes, i.e. before enabling dirty logging is visible to
- * userspace.
- *
- * Perform the TLB flush outside the mmu_lock to reduce the amount of
- * time the lock is held. However, this does mean that another CPU can
- * now grab mmu_lock and encounter a write-protected SPTE while CPUs
- * still have a writable mapping for the associated GFN in their TLB.
- *
- * This is safe but requires KVM to be careful when making decisions
- * based on the write-protection status of an SPTE. Specifically, KVM
- * also write-protects SPTEs to monitor changes to guest page tables
- * during shadow paging, and must guarantee no CPUs can write to those
- * page before the lock is dropped. As mentioned in the previous
- * paragraph, a write-protected SPTE is no guarantee that CPU cannot
- * perform writes. So to determine if a TLB flush is truly required, KVM
- * will clear a separate software-only bit (MMU-writable) and skip the
- * flush if-and-only-if this bit was already clear.
- *
- * See is_writable_pte() for more details.
- */
- if (flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
}
static inline bool need_topup(struct kvm_mmu_memory_cache *cache, int min)
@@ -6493,32 +6451,30 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
const struct kvm_memory_slot *memslot)
{
- bool flush = false;
-
if (kvm_memslots_have_rmaps(kvm)) {
write_lock(&kvm->mmu_lock);
/*
* Clear dirty bits only on 4k SPTEs since the legacy MMU only
* support dirty logging at a 4k granularity.
*/
- flush = slot_handle_level_4k(kvm, memslot, __rmap_clear_dirty, false);
+ slot_handle_level_4k(kvm, memslot, __rmap_clear_dirty, false);
write_unlock(&kvm->mmu_lock);
}
if (is_tdp_mmu_enabled(kvm)) {
read_lock(&kvm->mmu_lock);
- flush |= kvm_tdp_mmu_clear_dirty_slot(kvm, memslot);
+ kvm_tdp_mmu_clear_dirty_slot(kvm, memslot);
read_unlock(&kvm->mmu_lock);
}
/*
+ * The caller will flush the TLBs after this function returns.
+ *
* It's also safe to flush TLBs out of mmu lock here as currently this
* function is only used for dirty logging, in which case flushing TLB
* out of mmu lock also guarantees no dirty pages will be lost in
* dirty_bitmap.
*/
- if (flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
}
void kvm_mmu_zap_all(struct kvm *kvm)