diff options
| -rw-r--r-- | arch/x86/kvm/mmu.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c438224cca34..b7192236dcba 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2597,8 +2597,10 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, } } - if (pte_access & ACC_WRITE_MASK) + if (pte_access & ACC_WRITE_MASK) { mark_page_dirty(vcpu->kvm, gfn); + spte |= shadow_dirty_mask; + } set_pte: if (mmu_spte_update(sptep, spte)) @@ -2914,6 +2916,18 @@ fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, */ gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt); + /* + * Theoretically we could also set dirty bit (and flush TLB) here in + * order to eliminate unnecessary PML logging. See comments in + * set_spte. But fast_page_fault is very unlikely to happen with PML + * enabled, so we do not do this. This might result in the same GPA + * to be logged in PML buffer again when the write really happens, and + * eventually to be called by mark_page_dirty twice. But it's also no + * harm. This also avoids the TLB flush needed after setting dirty bit + * so non-PML cases won't be impacted. + * + * Compare with set_spte where instead shadow_dirty_mask is set. + */ if (cmpxchg64(sptep, spte, spte | PT_WRITABLE_MASK) == spte) mark_page_dirty(vcpu->kvm, gfn); |