KVM: nSVM: enable GMET for guests

All that needs to be done is moving the GMET bit from vmcb12 to vmcb02.
The only new thing is that __nested_copy_vmcb_control_to_cache now
ensures that ignored-if-unavailable bits are zero in svm->nested.ctl.

Tested-by: David Riley <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
This commit is contained in:
Paolo Bonzini committed 2026-05-10 14:55:08 +02:00
1 parent 878fffd76c
commit 687ee95c1b
2 files changed
+8 -1

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+5 -1
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@@ -489,11 +489,14 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu,
nested_svm_sanitize_intercept(vcpu, to, SKINIT);
nested_svm_sanitize_intercept(vcpu, to, RDPRU);
/* Always clear SVM_MISC_ENABLE_NP if the guest cannot use NPTs */
/* Always clear misc_ctl bits that the guest cannot use */
to->misc_ctl = from->misc_ctl;
if (!guest_cpu_cap_has(vcpu, X86_FEATURE_NPT))
to->misc_ctl &= ~SVM_MISC_ENABLE_NP;
if (!gmet_enabled || !guest_cpu_cap_has(vcpu, X86_FEATURE_GMET))
to->misc_ctl &= ~SVM_MISC_ENABLE_GMET;
to->iopm_base_pa = from->iopm_base_pa & PAGE_MASK;
to->msrpm_base_pa = from->msrpm_base_pa & PAGE_MASK;
to->tsc_offset = from->tsc_offset;
@@ -898,6 +901,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
/* Use vmcb01 MMU and format if guest does not use nNPT */
if (nested_npt_enabled(svm)) {
vmcb02->control.misc_ctl &= ~SVM_MISC_ENABLE_GMET;
vmcb02->control.misc_ctl |= (svm->nested.ctl.misc_ctl & SVM_MISC_ENABLE_GMET);
nested_svm_init_mmu_context(vcpu);
}
+3
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@@ -5504,6 +5504,9 @@ static __init void svm_set_cpu_caps(void)
if (boot_cpu_has(X86_FEATURE_PFTHRESHOLD))
kvm_cpu_cap_set(X86_FEATURE_PFTHRESHOLD);
if (gmet_enabled)
kvm_cpu_cap_set(X86_FEATURE_GMET);
if (vgif)
kvm_cpu_cap_set(X86_FEATURE_VGIF);