1 files changed, 51 insertions, 18 deletions

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c8dc25886c16..296c524988f9 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -99,6 +99,7 @@ static const struct svm_direct_access_msrs {
 	{ .index = MSR_IA32_SPEC_CTRL,			.always = false },
 	{ .index = MSR_IA32_PRED_CMD,			.always = false },
 	{ .index = MSR_IA32_FLUSH_CMD,			.always = false },
+	{ .index = MSR_IA32_DEBUGCTLMSR,		.always = false },
 	{ .index = MSR_IA32_LASTBRANCHFROMIP,		.always = false },
 	{ .index = MSR_IA32_LASTBRANCHTOIP,		.always = false },
 	{ .index = MSR_IA32_LASTINTFROMIP,		.always = false },
@@ -215,7 +216,7 @@ int vgif = true;
 module_param(vgif, int, 0444);
 
 /* enable/disable LBR virtualization */
-static int lbrv = true;
+int lbrv = true;
 module_param(lbrv, int, 0444);
 
 static int tsc_scaling = true;
@@ -990,7 +991,7 @@ void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb)
 	vmcb_mark_dirty(to_vmcb, VMCB_LBR);
 }
 
-static void svm_enable_lbrv(struct kvm_vcpu *vcpu)
+void svm_enable_lbrv(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
@@ -1000,6 +1001,9 @@ static void svm_enable_lbrv(struct kvm_vcpu *vcpu)
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTFROMIP, 1, 1);
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTTOIP, 1, 1);
 
+	if (sev_es_guest(vcpu->kvm))
+		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_DEBUGCTLMSR, 1, 1);
+
 	/* Move the LBR msrs to the vmcb02 so that the guest can see them. */
 	if (is_guest_mode(vcpu))
 		svm_copy_lbrs(svm->vmcb, svm->vmcb01.ptr);
@@ -1009,6 +1013,8 @@ static void svm_disable_lbrv(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	KVM_BUG_ON(sev_es_guest(vcpu->kvm), vcpu->kvm);
+
 	svm->vmcb->control.virt_ext &= ~LBR_CTL_ENABLE_MASK;
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTBRANCHFROMIP, 0, 0);
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTBRANCHTOIP, 0, 0);
@@ -2822,10 +2828,24 @@ static int svm_get_msr_feature(struct kvm_msr_entry *msr)
 	return 0;
 }
 
+static bool
+sev_es_prevent_msr_access(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
+{
+	return sev_es_guest(vcpu->kvm) &&
+	       vcpu->arch.guest_state_protected &&
+	       svm_msrpm_offset(msr_info->index) != MSR_INVALID &&
+	       !msr_write_intercepted(vcpu, msr_info->index);
+}
+
 static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	if (sev_es_prevent_msr_access(vcpu, msr_info)) {
+		msr_info->data = 0;
+		return -EINVAL;
+	}
+
 	switch (msr_info->index) {
 	case MSR_AMD64_TSC_RATIO:
 		if (!msr_info->host_initiated &&
@@ -2976,6 +2996,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 
 	u32 ecx = msr->index;
 	u64 data = msr->data;
+
+	if (sev_es_prevent_msr_access(vcpu, msr))
+		return -EINVAL;
+
 	switch (ecx) {
 	case MSR_AMD64_TSC_RATIO:
 
@@ -3846,16 +3870,27 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
 	struct vcpu_svm *svm = to_svm(vcpu);
 
 	/*
-	 * KVM should never request an NMI window when vNMI is enabled, as KVM
-	 * allows at most one to-be-injected NMI and one pending NMI, i.e. if
-	 * two NMIs arrive simultaneously, KVM will inject one and set
-	 * V_NMI_PENDING for the other.  WARN, but continue with the standard
-	 * single-step approach to try and salvage the pending NMI.
+	 * If NMIs are outright masked, i.e. the vCPU is already handling an
+	 * NMI, and KVM has not yet intercepted an IRET, then there is nothing
+	 * more to do at this time as KVM has already enabled IRET intercepts.
+	 * If KVM has already intercepted IRET, then single-step over the IRET,
+	 * as NMIs aren't architecturally unmasked until the IRET completes.
+	 *
+	 * If vNMI is enabled, KVM should never request an NMI window if NMIs
+	 * are masked, as KVM allows at most one to-be-injected NMI and one
+	 * pending NMI.  If two NMIs arrive simultaneously, KVM will inject one
+	 * NMI and set V_NMI_PENDING for the other, but if and only if NMIs are
+	 * unmasked.  KVM _will_ request an NMI window in some situations, e.g.
+	 * if the vCPU is in an STI shadow or if GIF=0, KVM can't immediately
+	 * inject the NMI.  In those situations, KVM needs to single-step over
+	 * the STI shadow or intercept STGI.
 	 */
-	WARN_ON_ONCE(is_vnmi_enabled(svm));
+	if (svm_get_nmi_mask(vcpu)) {
+		WARN_ON_ONCE(is_vnmi_enabled(svm));
 
-	if (svm_get_nmi_mask(vcpu) && !svm->awaiting_iret_completion)
-		return; /* IRET will cause a vm exit */
+		if (!svm->awaiting_iret_completion)
+			return; /* IRET will cause a vm exit */
+	}
 
 	/*
 	 * SEV-ES guests are responsible for signaling when a vCPU is ready to
@@ -5265,6 +5300,12 @@ static __init int svm_hardware_setup(void)
 
 	nrips = nrips && boot_cpu_has(X86_FEATURE_NRIPS);
 
+	if (lbrv) {
+		if (!boot_cpu_has(X86_FEATURE_LBRV))
+			lbrv = false;
+		else
+			pr_info("LBR virtualization supported\n");
+	}
 	/*
 	 * Note, SEV setup consumes npt_enabled and enable_mmio_caching (which
 	 * may be modified by svm_adjust_mmio_mask()), as well as nrips.
@@ -5318,14 +5359,6 @@ static __init int svm_hardware_setup(void)
 		svm_x86_ops.set_vnmi_pending = NULL;
 	}
 
-
-	if (lbrv) {
-		if (!boot_cpu_has(X86_FEATURE_LBRV))
-			lbrv = false;
-		else
-			pr_info("LBR virtualization supported\n");
-	}
-
 	if (!enable_pmu)
 		pr_info("PMU virtualization is disabled\n");