diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 84335d119ff1..2ea648e4c97a 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -425,6 +425,18 @@ issued by the hypervisor to make the guest ready for execution. Returns: 0 on success, -negative on error +Device attribute API +==================== + +Attributes of the SEV implementation can be retrieved through the +``KVM_HAS_DEVICE_ATTR`` and ``KVM_GET_DEVICE_ATTR`` ioctls on the ``/dev/kvm`` +device node, using group ``KVM_X86_GRP_SEV``. + +Currently only one attribute is implemented: + +* ``KVM_X86_SEV_VMSA_FEATURES``: return the set of all bits that + are accepted in the ``vmsa_features`` of ``KVM_SEV_INIT2``. + Firmware Management =================== diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index ef11aa4cab42..b7dc515f4c27 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -457,8 +457,13 @@ struct kvm_sync_regs { #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 -/* attributes for system fd (group 0) */ -#define KVM_X86_XCOMP_GUEST_SUPP 0 +/* vendor-independent attributes for system fd (group 0) */ +#define KVM_X86_GRP_SYSTEM 0 +# define KVM_X86_XCOMP_GUEST_SUPP 0 + +/* vendor-specific groups and attributes for system fd */ +#define KVM_X86_GRP_SEV 1 +# define KVM_X86_SEV_VMSA_FEATURES 0 struct kvm_vmx_nested_state_data { __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 5d41f27a8af5..5055935dfd1d 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -46,6 +46,7 @@ module_param_named(sev_es, sev_es_enabled, bool, 0444); /* enable/disable SEV-ES DebugSwap support */ static bool sev_es_debug_swap_enabled = false; module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444); +static u64 sev_supported_vmsa_features; static u8 sev_enc_bit; static DECLARE_RWSEM(sev_deactivate_lock); @@ -603,8 +604,8 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm) save->xss = svm->vcpu.arch.ia32_xss; save->dr6 = svm->vcpu.arch.dr6; - if (sev_es_debug_swap_enabled) { - save->sev_features |= SVM_SEV_FEAT_DEBUG_SWAP; + if (sev_supported_vmsa_features) { + save->sev_features = sev_supported_vmsa_features; pr_warn_once("Enabling DebugSwap with KVM_SEV_ES_INIT. " "This will not work starting with Linux 6.10\n"); } @@ -1843,6 +1844,21 @@ out_fput: return ret; } +int sev_dev_get_attr(u32 group, u64 attr, u64 *val) +{ + if (group != KVM_X86_GRP_SEV) + return -ENXIO; + + switch (attr) { + case KVM_X86_SEV_VMSA_FEATURES: + *val = sev_supported_vmsa_features; + return 0; + + default: + return -ENXIO; + } +} + int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) { struct kvm_sev_cmd sev_cmd; @@ -2275,6 +2291,10 @@ out: 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; + + sev_supported_vmsa_features = 0; + if (sev_es_debug_swap_enabled) + sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP; } void sev_hardware_unsetup(void) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e7f47a1f3eb1..450535d6757f 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5026,6 +5026,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { #endif #ifdef CONFIG_KVM_AMD_SEV + .dev_get_attr = sev_dev_get_attr, .mem_enc_ioctl = sev_mem_enc_ioctl, .mem_enc_register_region = sev_mem_enc_register_region, .mem_enc_unregister_region = sev_mem_enc_unregister_region, diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index ec8ca7d92cf1..1c6601a9cbbf 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -692,6 +692,7 @@ void __init sev_set_cpu_caps(void); void __init sev_hardware_setup(void); void sev_hardware_unsetup(void); int sev_cpu_init(struct svm_cpu_data *sd); +int sev_dev_get_attr(u32 group, u64 attr, u64 *val); extern unsigned int max_sev_asid; #else static inline struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) { @@ -704,6 +705,7 @@ static inline void __init sev_set_cpu_caps(void) {} static inline void __init sev_hardware_setup(void) {} static inline void sev_hardware_unsetup(void) {} static inline int sev_cpu_init(struct svm_cpu_data *sd) { return 0; } +static inline int sev_dev_get_attr(u32 group, u64 attr, u64 *val) { return -ENXIO; } #define max_sev_asid 0 #endif