Commit daa5b6c1 authored Oct 14, 2020 by Ben Gardon Committed by Paolo Bonzini Oct 23, 2020

kvm: x86/mmu: Don't clear write flooding count for direct roots

Direct roots don't have a write flooding count because the guest can't
affect that paging structure. Thus there's no need to clear the write
flooding count on a fast CR3 switch for direct roots.

Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell
machine. This series introduced no new failures.

This series can be viewed in Gerrit at:
	https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538



Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20201014182700.2888246-20-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 95fb5b02

arch/x86/kvm/mmu/mmu.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -3892,7 +3892,13 @@ static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd,
		*/
		vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);

		__clear_sp_write_flooding_count(to_shadow_page(vcpu->arch.mmu->root_hpa));
		/*
		* If this is a direct root page, it doesn't have a write flooding
		* count. Otherwise, clear the write flooding count.
		*/
		if (!new_role.direct)
		__clear_sp_write_flooding_count(
		to_shadow_page(vcpu->arch.mmu->root_hpa));
		}

		void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd, bool skip_tlb_flush,

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