diff mbox series

[v13,08/26] KVM: SEV: Add initial SEV-SNP support

Message ID 20240418194133.1452059-9-michael.roth@amd.com (mailing list archive)
State New
Headers show
Series Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand

Commit Message

Michael Roth April 18, 2024, 7:41 p.m. UTC 
SEV-SNP builds upon existing SEV and SEV-ES functionality while adding
new hardware-based security protection. SEV-SNP adds strong memory
encryption and integrity protection to help prevent malicious
hypervisor-based attacks such as data replay, memory re-mapping, and
more, to create an isolated execution environment.

Define a new KVM_X86_SNP_VM type which makes use of these capabilities
and extend the KVM_SEV_INIT2 ioctl to support it. Also add a basic
helper to check whether SNP is enabled.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
[mdr: commit fixups, use similar ASID reporting as with SEV/SEV-ES]
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 arch/x86/include/asm/svm.h      |  3 ++-
 arch/x86/include/uapi/asm/kvm.h |  1 +
 arch/x86/kvm/svm/sev.c          | 21 ++++++++++++++++++++-
 arch/x86/kvm/svm/svm.c          |  3 ++-
 arch/x86/kvm/svm/svm.h          | 12 ++++++++++++
 arch/x86/kvm/x86.c              |  2 +-
 6 files changed, 38 insertions(+), 4 deletions(-)

Comments

Paolo Bonzini April 19, 2024, 11:58 a.m. UTC | #1 
On Thu, Apr 18, 2024 at 9:51 PM Michael Roth <michael.roth@amd.com> wrote:
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 535018f152a3..d31404953bf1 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -4899,7 +4899,8 @@ static int svm_vm_init(struct kvm *kvm)
>
>         if (type != KVM_X86_DEFAULT_VM &&
>             type != KVM_X86_SW_PROTECTED_VM) {
> -               kvm->arch.has_protected_state = (type == KVM_X86_SEV_ES_VM);
> +               kvm->arch.has_protected_state =
> +                       (type == KVM_X86_SEV_ES_VM || type == KVM_X86_SNP_VM);

I'd rather set has_private_mem here too, rather than in x86.c

Also this patch is the place to have

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d31404953bf1..6209f70ab11a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2056,6 +2056,9 @@ static int npf_interception(struct kvm_vcpu *vcpu)
     if (WARN_ON_ONCE(error_code & PFERR_SYNTHETIC_MASK))
         error_code &= ~PFERR_SYNTHETIC_MASK;

+    if (sev_snp_guest(vcpu) && (error_code & PFERR_GUEST_ENC_MASK))
+        error_code |= PFERR_PRIVATE_ACCESS;
+
     trace_kvm_page_fault(vcpu, fault_address, error_code);
     return kvm_mmu_page_fault(vcpu, fault_address, error_code,
             static_cpu_has(X86_FEATURE_DECODEASSISTS) ?


for the final shape of the MMU changes.

Paolo

> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 83b8260443a3..9923921904a2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12598,7 +12598,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>
>         kvm->arch.vm_type = type;
>         kvm->arch.has_private_mem =
> -               (type == KVM_X86_SW_PROTECTED_VM);
> +               (type == KVM_X86_SW_PROTECTED_VM || type == KVM_X86_SNP_VM);
>
>         ret = kvm_page_track_init(kvm);
>         if (ret)
> --
> 2.25.1
>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 728c98175b9c..544a43c1cf11 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -285,7 +285,8 @@  static_assert((X2AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == X2AVIC_
 
 #define AVIC_HPA_MASK	~((0xFFFULL << 52) | 0xFFF)
 
-#define SVM_SEV_FEAT_DEBUG_SWAP                        BIT(5)
+#define SVM_SEV_FEAT_SNP_ACTIVE				BIT(0)
+#define SVM_SEV_FEAT_DEBUG_SWAP				BIT(5)
 
 struct vmcb_seg {
 	u16 selector;
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 72ad5ace118d..9a8b81d20314 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -872,5 +872,6 @@  struct kvm_hyperv_eventfd {
 #define KVM_X86_SW_PROTECTED_VM	1
 #define KVM_X86_SEV_VM		2
 #define KVM_X86_SEV_ES_VM	3
+#define KVM_X86_SNP_VM		4
 
 #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1d2264e93afe..c41cc73a1efe 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -46,6 +46,9 @@  module_param_named(sev, sev_enabled, bool, 0444);
 static bool sev_es_enabled = true;
 module_param_named(sev_es, sev_es_enabled, bool, 0444);
 
+/* enable/disable SEV-SNP support */
+static bool sev_snp_enabled;
+
 /* 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);
@@ -275,6 +278,9 @@  static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
 	sev->es_active = es_active;
 	sev->vmsa_features = data->vmsa_features;
 
+	if (vm_type == KVM_X86_SNP_VM)
+		sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
+
 	ret = sev_asid_new(sev);
 	if (ret)
 		goto e_no_asid;
@@ -326,7 +332,8 @@  static int sev_guest_init2(struct kvm *kvm, struct kvm_sev_cmd *argp)
 		return -EINVAL;
 
 	if (kvm->arch.vm_type != KVM_X86_SEV_VM &&
-	    kvm->arch.vm_type != KVM_X86_SEV_ES_VM)
+	    kvm->arch.vm_type != KVM_X86_SEV_ES_VM &&
+	    kvm->arch.vm_type != KVM_X86_SNP_VM)
 		return -EINVAL;
 
 	if (copy_from_user(&data, u64_to_user_ptr(argp->data), sizeof(data)))
@@ -2306,11 +2313,16 @@  void __init sev_set_cpu_caps(void)
 		kvm_cpu_cap_set(X86_FEATURE_SEV_ES);
 		kvm_caps.supported_vm_types |= BIT(KVM_X86_SEV_ES_VM);
 	}
+	if (sev_snp_enabled) {
+		kvm_cpu_cap_set(X86_FEATURE_SEV_SNP);
+		kvm_caps.supported_vm_types |= BIT(KVM_X86_SNP_VM);
+	}
 }
 
 void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
+	bool sev_snp_supported = false;
 	bool sev_es_supported = false;
 	bool sev_supported = false;
 
@@ -2391,6 +2403,7 @@  void __init sev_hardware_setup(void)
 	sev_es_asid_count = min_sev_asid - 1;
 	WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
 	sev_es_supported = true;
+	sev_snp_supported = sev_snp_enabled && cc_platform_has(CC_ATTR_HOST_SEV_SNP);
 
 out:
 	if (boot_cpu_has(X86_FEATURE_SEV))
@@ -2403,9 +2416,15 @@  void __init sev_hardware_setup(void)
 		pr_info("SEV-ES %s (ASIDs %u - %u)\n",
 			sev_es_supported ? "enabled" : "disabled",
 			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+	if (boot_cpu_has(X86_FEATURE_SEV_SNP))
+		pr_info("SEV-SNP %s (ASIDs %u - %u)\n",
+			sev_snp_supported ? "enabled" : "disabled",
+			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
 
 	sev_enabled = sev_supported;
 	sev_es_enabled = sev_es_supported;
+	sev_snp_enabled = sev_snp_supported;
+
 	if (!sev_es_enabled || !cpu_feature_enabled(X86_FEATURE_DEBUG_SWAP) ||
 	    !cpu_feature_enabled(X86_FEATURE_NO_NESTED_DATA_BP))
 		sev_es_debug_swap_enabled = false;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 535018f152a3..d31404953bf1 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4899,7 +4899,8 @@  static int svm_vm_init(struct kvm *kvm)
 
 	if (type != KVM_X86_DEFAULT_VM &&
 	    type != KVM_X86_SW_PROTECTED_VM) {
-		kvm->arch.has_protected_state = (type == KVM_X86_SEV_ES_VM);
+		kvm->arch.has_protected_state =
+			(type == KVM_X86_SEV_ES_VM || type == KVM_X86_SNP_VM);
 		to_kvm_sev_info(kvm)->need_init = true;
 	}
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 6fd0f5862681..7f2e9c7fc4ca 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -348,6 +348,18 @@  static __always_inline bool sev_es_guest(struct kvm *kvm)
 #endif
 }
 
+static __always_inline bool sev_snp_guest(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_AMD_SEV
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	return (sev->vmsa_features & SVM_SEV_FEAT_SNP_ACTIVE) &&
+	       !WARN_ON_ONCE(!sev_es_guest(kvm));
+#else
+	return false;
+#endif
+}
+
 static inline void vmcb_mark_all_dirty(struct vmcb *vmcb)
 {
 	vmcb->control.clean = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 83b8260443a3..9923921904a2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12598,7 +12598,7 @@  int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 	kvm->arch.vm_type = type;
 	kvm->arch.has_private_mem =
-		(type == KVM_X86_SW_PROTECTED_VM);
+		(type == KVM_X86_SW_PROTECTED_VM || type == KVM_X86_SNP_VM);
 
 	ret = kvm_page_track_init(kvm);
 	if (ret)