From: Vitaly Kuznetsov Date: Fri, 10 Jul 2020 14:11:57 +0000 (+0200) Subject: KVM: x86: drop superfluous mmu_check_root() from fast_pgd_switch() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fe9304d31831c9ee3943f9a6f72b7cea16d4bc11;p=linux.git KVM: x86: drop superfluous mmu_check_root() from fast_pgd_switch() The mmu_check_root() check in fast_pgd_switch() seems to be superfluous: when GPA is outside of the visible range cached_root_available() will fail for non-direct roots (as we can't have a matching one on the list) and we don't seem to care for direct ones. Also, raising #TF immediately when a non-existent GFN is written to CR3 doesn't seem to mach architectural behavior. Drop the check. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200710141157.1640173-10-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 61c35fec5219c..613c33149428d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4243,8 +4243,7 @@ static bool fast_pgd_switch(struct kvm_vcpu *vcpu, gpa_t new_pgd, */ if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL && mmu->root_level >= PT64_ROOT_4LEVEL) - return !mmu_check_root(vcpu, new_pgd >> PAGE_SHIFT) && - cached_root_available(vcpu, new_pgd, new_role); + return cached_root_available(vcpu, new_pgd, new_role); return false; }