diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-10-27 16:23:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-16 10:29:53 +0100 |
| commit | 1b08d2ab698ddf78833717908e2a41336ab9c6ef (patch) | |
| tree | 4630021500be77301994f38cdad4050349c6a78d /arch/x86/kvm/svm.c | |
| parent | 52644d80850a3fe965ee964e903acef7be61a62c (diff) | |
KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active
commit 9167ab79936206118cc60e47dcb926c3489f3bd5 upstream.
VMX already does so if the host has SMEP, in order to support the combination of
CR0.WP=1 and CR4.SMEP=1. However, it is perfectly safe to always do so, and in
fact VMX already ends up running with EFER.NXE=1 on old processors that lack the
"load EFER" controls, because it may help avoiding a slow MSR write. Removing
all the conditionals simplifies the code.
SVM does not have similar code, but it should since recent AMD processors do
support SMEP. So this patch also makes the code for the two vendors more similar
while fixing NPT=0, CR0.WP=1 and CR4.SMEP=1 on AMD processors.
Cc: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 4.9: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f7a7b98b3271..1079228e4fef 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -590,8 +590,14 @@ static int get_npt_level(void) static void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer) { vcpu->arch.efer = efer; - if (!npt_enabled && !(efer & EFER_LMA)) - efer &= ~EFER_LME; + + if (!npt_enabled) { + /* Shadow paging assumes NX to be available. */ + efer |= EFER_NX; + + if (!(efer & EFER_LMA)) + efer &= ~EFER_LME; + } to_svm(vcpu)->vmcb->save.efer = efer | EFER_SVME; mark_dirty(to_svm(vcpu)->vmcb, VMCB_CR); |