From: Sean Christopherson Date: Mon, 7 Jun 2021 09:01:57 +0000 (+0300) Subject: KVM: nSVM: Drop pointless pdptrs_changed() check on nested transition X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a36dbec67e26febc1fc551f4819e3c058b25e79c;p=linux.git KVM: nSVM: Drop pointless pdptrs_changed() check on nested transition Remove the "PDPTRs unchanged" check to skip PDPTR loading during nested SVM transitions as it's not at all an optimization. Reading guest memory to get the PDPTRs isn't magically cheaper by doing it in pdptrs_changed(), and if the PDPTRs did change, KVM will end up doing the read twice. Signed-off-by: Sean Christopherson Message-Id: <20210607090203.133058-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 34fc74b0d58a3..f0a7f8432527e 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -391,10 +391,8 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, return -EINVAL; if (!nested_npt && is_pae_paging(vcpu) && - (cr3 != kvm_read_cr3(vcpu) || pdptrs_changed(vcpu))) { - if (CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))) - return -EINVAL; - } + CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))) + return -EINVAL; /* * TODO: optimize unconditional TLB flush/MMU sync here and in