[PATCH v4 7/7] KVM: SVM: Enable Restricted Injection for an SEV-SNP guest

[Melody Wang <huibo.wang@amd.com>]

Enable Restricted Injection in an SEV-SNP guest by setting the corresponding
bit in the VMSA SEV features field (SEV_FEATURES[3]) from QEMU.

Add Restricted Injection to the supported hypervisor features.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/asm/cpufeatures.h |  1 +
 arch/x86/include/asm/sev-common.h  |  1 +
 arch/x86/kvm/svm/sev.c             | 26 +++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index de7bd88e539d..dc35806ff05e 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -453,6 +453,7 @@
 #define X86_FEATURE_SNP_SECURE_TSC	(19*32+ 8) /* SEV-SNP Secure TSC */
 #define X86_FEATURE_V_TSC_AUX		(19*32+ 9) /* Virtual TSC_AUX */
 #define X86_FEATURE_SME_COHERENT	(19*32+10) /* hardware-enforced cache coherency */
+#define X86_FEATURE_RESTRICTED_INJECTION (19*32+12) /* Restricted Injection */
 #define X86_FEATURE_DEBUG_SWAP		(19*32+14) /* "debug_swap" SEV-ES full debug state swap support */
 #define X86_FEATURE_RMPREAD		(19*32+21) /* RMPREAD instruction */
 #define X86_FEATURE_SEGMENTED_RMP	(19*32+23) /* Segmented RMP support */
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 01a6e4dbe423..ee17a3541b55 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -136,6 +136,7 @@ enum psc_op {
 
 #define GHCB_HV_FT_SNP			BIT_ULL(0)
 #define GHCB_HV_FT_SNP_AP_CREATION	BIT_ULL(1)
+#define GHCB_HV_FT_SNP_RINJ		(BIT_ULL(2) | GHCB_HV_FT_SNP_AP_CREATION)
 #define GHCB_HV_FT_SNP_MULTI_VMPL	BIT_ULL(5)
 
 /*
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 95ee199e38fb..c26575516eec 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -40,7 +40,9 @@
 #define GHCB_VERSION_MAX	2ULL
 #define GHCB_VERSION_MIN	1ULL
 
-#define GHCB_HV_FT_SUPPORTED	(GHCB_HV_FT_SNP | GHCB_HV_FT_SNP_AP_CREATION)
+#define GHCB_HV_FT_SUPPORTED	(GHCB_HV_FT_SNP |		\
+				 GHCB_HV_FT_SNP_AP_CREATION |	\
+				 GHCB_HV_FT_SNP_RINJ)
 
 /*
  * The GHCB spec essentially states that all non-zero error codes other than
@@ -64,6 +66,10 @@ module_param_named(sev_es, sev_es_enabled, bool, 0444);
 static bool __ro_after_init sev_snp_enabled = true;
 module_param_named(sev_snp, sev_snp_enabled, bool, 0444);
 
+/* enable/disable SEV-SNP Restricted Injection support */
+static bool sev_snp_restricted_injection_enabled = true;
+module_param_named(restricted_injection, sev_snp_restricted_injection_enabled, bool, 0444);
+
 static unsigned int __ro_after_init nr_ciphertext_hiding_asids;
 module_param_named(ciphertext_hiding_asids, nr_ciphertext_hiding_asids, uint, 0444);
 
@@ -3224,6 +3230,12 @@ void __init sev_hardware_setup(void)
 
 	if (sev_snp_enabled && tsc_khz && cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC))
 		sev_supported_vmsa_features |= SVM_SEV_FEAT_SECURE_TSC;
+
+	if (!sev_snp_enabled || !cpu_feature_enabled(X86_FEATURE_RESTRICTED_INJECTION))
+		sev_snp_restricted_injection_enabled = false;
+
+	if (sev_snp_restricted_injection_enabled)
+		sev_supported_vmsa_features |= SVM_SEV_FEAT_RESTRICTED_INJECTION;
 }
 
 void sev_hardware_unsetup(void)
@@ -4740,10 +4752,20 @@ void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm)
 		vcpu->arch.reserved_gpa_bits &= ~(1UL << (best->ebx & 0x3f));
 }
 
+static void sev_snp_init_vmcb(struct vcpu_svm *svm)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
+
+	/* V_NMI is not supported when Restricted Injection is enabled */
+	if (sev->vmsa_features & SVM_SEV_FEAT_RESTRICTED_INJECTION)
+		svm->vmcb->control.int_ctl &= ~V_NMI_ENABLE_MASK;
+}
+
 static void sev_es_init_vmcb(struct vcpu_svm *svm, bool init_event)
 {
 	struct kvm_sev_info *sev = to_kvm_sev_info(svm->vcpu.kvm);
 	struct vmcb *vmcb = svm->vmcb01.ptr;
+	struct kvm_vcpu *vcpu = &svm->vcpu;
 
 	svm->vmcb->control.misc_ctl |= SVM_MISC_ENABLE_SEV_ES;
 
@@ -4810,6 +4832,8 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm, bool init_event)
 		set_ghcb_msr(svm, GHCB_MSR_SEV_INFO((__u64)sev->ghcb_version,
 						    GHCB_VERSION_MIN,
 						    sev_enc_bit));
+	if (is_sev_snp_guest(vcpu))
+		sev_snp_init_vmcb(svm);
 }
 
 void sev_init_vmcb(struct vcpu_svm *svm, bool init_event)
-- 
2.43.0