linux-kernel - [PATCH v3 7/7] KVM: SVM: Enable restricted injection for an SEV-SNP guest

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Message-ID: <20241127225539.5567-8-huibo.wang@amd.com>
Date: Wed, 27 Nov 2024 22:55:39 +0000
From: Melody Wang <huibo.wang@....com>
To: <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <x86@...nel.org>
CC: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini
	<pbonzini@...hat.com>, Tom Lendacky <thomas.lendacky@....com>, "Neeraj
 Upadhyay" <neeraj.upadhyay@....com>, Ashish Kalra <ashish.kalra@....com>,
	Michael Roth <michael.roth@....com>, Pankaj Gupta <pankaj.gupta@....com>,
	Melody Wang <huibo.wang@....com>
Subject: [PATCH v3 7/7] KVM: SVM: Enable restricted injection for an SEV-SNP guest

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

Add the restricted injection supporting the hypervisor advertised features.

Co-developed-by: Thomas Lendacky <thomas.lendacky@....com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@....com>
Signed-off-by: Melody Wang <huibo.wang@....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 d96277dceabf..c0a409ac1ea3 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -450,6 +450,7 @@
 #define X86_FEATURE_SEV_SNP		(19*32+ 4) /* "sev_snp" AMD Secure Encrypted Virtualization - Secure Nested Paging */
 #define X86_FEATURE_V_TSC_AUX		(19*32+ 9) /* Virtual TSC_AUX */
 #define X86_FEATURE_SME_COHERENT	(19*32+10) /* AMD hardware-enforced cache coherency */
+#define X86_FEATURE_RESTRICTED_INJECTION	(19*32+12) /* AMD SEV Restricted Injection */
 #define X86_FEATURE_DEBUG_SWAP		(19*32+14) /* "debug_swap" AMD SEV-ES full debug state swap support */
 #define X86_FEATURE_SVSM		(19*32+28) /* "svsm" SVSM present */
 
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 98726c2b04f8..f409893ad1a5 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 5e8fc8cf2d0d..d2a1b4304e41 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -40,7 +40,9 @@
 #define GHCB_VERSION_DEFAULT	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)
 
 /* enable/disable SEV support */
 static bool sev_enabled = true;
@@ -57,6 +59,10 @@ module_param_named(sev_snp, sev_snp_enabled, bool, 0444);
 /* enable/disable SEV-ES DebugSwap support */
 static bool sev_es_debug_swap_enabled = true;
 module_param_named(debug_swap, sev_es_debug_swap_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 u64 sev_supported_vmsa_features;
 
 #define AP_RESET_HOLD_NONE		0
@@ -3083,6 +3089,12 @@ void __init sev_hardware_setup(void)
 	sev_supported_vmsa_features = 0;
 	if (sev_es_debug_swap_enabled)
 		sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP;
+
+	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)
@@ -4589,6 +4601,15 @@ void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm)
 		sev_es_vcpu_after_set_cpuid(svm);
 }
 
+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)
 {
 	struct vmcb *vmcb = svm->vmcb01.ptr;
@@ -4646,6 +4667,9 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
 	/* Clear intercepts on selected MSRs */
 	set_msr_interception(vcpu, svm->msrpm, MSR_EFER, 1, 1);
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_CR_PAT, 1, 1);
+
+	if (sev_snp_guest(vcpu->kvm))
+		sev_snp_init_vmcb(svm);
 }
 
 void sev_init_vmcb(struct vcpu_svm *svm)
-- 
2.34.1