KVM: SVM: detect opening of SMI window using STGI intercept
Commit 05cade71cf3b ("KVM: nSVM: fix SMI injection in guest mode") made
KVM mask SMI if GIF=0 but it didn't do anything to unmask it when GIF is
enabled.
The issue manifests for me as a significantly longer boot time of Windows
guests when running with SMM-enabled OVMF.
This commit fixes it by intercepting STGI instead of requesting immediate
exit if the reason why SMM was masked is GIF.
Fixes: 05cade71cf3b ("KVM: nSVM: fix SMI injection in guest mode")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ff94552..b71daed 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3187,7 +3187,7 @@ static int stgi_interception(struct vcpu_svm *svm)
/*
* If VGIF is enabled, the STGI intercept is only added to
- * detect the opening of the NMI window; remove it now.
+ * detect the opening of the SMI/NMI window; remove it now.
*/
if (vgif_enabled(svm))
clr_intercept(svm, INTERCEPT_STGI);
@@ -5476,6 +5476,19 @@ static int svm_pre_leave_smm(struct kvm_vcpu *vcpu, u64 smbase)
return ret;
}
+static int enable_smi_window(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (!gif_set(svm)) {
+ if (vgif_enabled(svm))
+ set_intercept(svm, INTERCEPT_STGI);
+ /* STGI will cause a vm exit */
+ return 1;
+ }
+ return 0;
+}
+
static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -5590,6 +5603,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.smi_allowed = svm_smi_allowed,
.pre_enter_smm = svm_pre_enter_smm,
.pre_leave_smm = svm_pre_leave_smm,
+ .enable_smi_window = enable_smi_window,
};
static int __init svm_init(void)