From c2a4eadf7747a1359a80ede64e4ae0e0ba64ca08 Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Tue, 24 Jul 2018 08:17:07 +0000 Subject: [PATCH] KVM/MMU: Combine flushing remote tlb in mmu_set_spte() mmu_set_spte() flushes remote tlbs for drop_parent_pte/drop_spte() and set_spte() separately. This may introduce redundant flush. This patch is to combine these flushes and check flush request after calling set_spte(). Signed-off-by: Lan Tianyu Reviewed-by: Junaid Shahid Reviewed-by: Xiao Guangrong Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 22a7984..8f21632 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2901,6 +2901,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, int rmap_count; int set_spte_ret; int ret = RET_PF_RETRY; + bool flush = false; pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__, *sptep, write_fault, gfn); @@ -2917,12 +2918,12 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, child = page_header(pte & PT64_BASE_ADDR_MASK); drop_parent_pte(child, sptep); - kvm_flush_remote_tlbs(vcpu->kvm); + flush = true; } else if (pfn != spte_to_pfn(*sptep)) { pgprintk("hfn old %llx new %llx\n", spte_to_pfn(*sptep), pfn); drop_spte(vcpu->kvm, sptep); - kvm_flush_remote_tlbs(vcpu->kvm); + flush = true; } else was_rmapped = 1; } @@ -2934,7 +2935,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, ret = RET_PF_EMULATE; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); } - if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH) + if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH || flush) kvm_flush_remote_tlbs(vcpu->kvm); if (unlikely(is_mmio_spte(*sptep))) -- 2.7.4