From 1dfe571c12cf99244b933208fb77f29471ded677 Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Wed, 1 May 2024 03:51:54 -0500 Subject: [PATCH] KVM: SEV: Add initial SEV-SNP support 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 and set PFERR_PRIVATE_ACCESS for private #NPFs so they are handled appropriately by KVM MMU. Signed-off-by: Brijesh Singh Co-developed-by: Michael Roth Signed-off-by: Michael Roth Signed-off-by: Ashish Kalra Reviewed-by: Paolo Bonzini Message-ID: <20240501085210.2213060-5-michael.roth@amd.com> Signed-off-by: Paolo Bonzini --- 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 | 8 +++++++- arch/x86/kvm/svm/svm.h | 12 ++++++++++++ 5 files changed, 42 insertions(+), 3 deletions(-) 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 9fae1b73b529..d2ae5fcc0275 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -874,5 +874,6 @@ 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 0623cfaa7bb0..b3345d45b989 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -47,6 +47,9 @@ 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); @@ -288,6 +291,9 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp, if (sev->es_active && !sev->ghcb_version) sev->ghcb_version = GHCB_VERSION_DEFAULT; + 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; @@ -348,7 +354,8 @@ 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))) @@ -2328,11 +2335,16 @@ 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; @@ -2413,6 +2425,7 @@ 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)) @@ -2425,9 +2438,15 @@ out: 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 c8dc25886c16..66d5e2e46a66 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2057,6 +2057,9 @@ 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->kvm) && (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) ? @@ -4902,8 +4905,11 @@ 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; + + kvm->arch.has_private_mem = (type == KVM_X86_SNP_VM); } if (!pause_filter_count || !pause_filter_thresh) diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index be57213cd295..583e035d38f8 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -349,6 +349,18 @@ 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;