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Commit c2a4eadf authored by Tianyu Lan's avatar Tianyu Lan Committed by Paolo Bonzini
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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: default avatarLan Tianyu <Tianyu.Lan@microsoft.com>
Reviewed-by: default avatarJunaid Shahid <junaids@google.com>
Reviewed-by: default avatarXiao Guangrong <xiaoguangrong@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5e079c7e

arch/x86/kvm/mmu.c

+4 −3
Original line number Original line Diff line number Diff line
@@ -2901,6 +2901,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, 
	int rmap_count;

	int rmap_count;

	int set_spte_ret;

	int set_spte_ret;

	int ret = RET_PF_RETRY;

	int ret = RET_PF_RETRY;

	bool flush = false;





	pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,

	pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,

		 *sptep, write_fault, gfn);

		 *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);

			child = page_header(pte & PT64_BASE_ADDR_MASK);

			drop_parent_pte(child, sptep);

			drop_parent_pte(child, sptep);

			kvm_flush_remote_tlbs(vcpu->kvm);

			flush = true;

		} else if (pfn != spte_to_pfn(*sptep)) {

		} else if (pfn != spte_to_pfn(*sptep)) {

			pgprintk("hfn old %llx new %llx\n",

			pgprintk("hfn old %llx new %llx\n",

				 spte_to_pfn(*sptep), pfn);

				 spte_to_pfn(*sptep), pfn);

			drop_spte(vcpu->kvm, sptep);

			drop_spte(vcpu->kvm, sptep);

			kvm_flush_remote_tlbs(vcpu->kvm);

			flush = true;

		} else

		} else

			was_rmapped = 1;

			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;

			ret = RET_PF_EMULATE;

		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);

		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);

		kvm_flush_remote_tlbs(vcpu->kvm);





	if (unlikely(is_mmio_spte(*sptep)))

	if (unlikely(is_mmio_spte(*sptep)))