On 8/2/2024 7:27 AM, Kim Phillips wrote: > From: Kishon Vijay Abraham I <kvijayab@xxxxxxx> > > AMD EPYC 5th generation processors have introduced a feature that allows > the hypervisor to control the SEV_FEATURES that are set for or by a > guest [1]. The ALLOWED_SEV_FEATURES feature can be used by the hypervisor > to enforce that SEV-ES and SEV-SNP guests cannot enable features that the > hypervisor does not want to be enabled. > > When ALLOWED_SEV_FEATURES is enabled, a VMRUN will fail if any > non-reserved bits are 1 in SEV_FEATURES but are 0 in > ALLOWED_SEV_FEATURES. > > [1] Section 15.36.20 "Allowed SEV Features", AMD64 Architecture > Programmer's Manual, Pub. 24593 Rev. 3.42 - March 2024: > https://bugzilla.kernel.org/attachment.cgi?id=306250 > > Signed-off-by: Kishon Vijay Abraham I <kvijayab@xxxxxxx> > Signed-off-by: Kim Phillips <kim.phillips@xxxxxxx> Looks good to me. Reviewed-by: Nikunj A. Dadhania <nikunj@xxxxxxx> > --- > arch/x86/include/asm/svm.h | 6 +++++- > arch/x86/kvm/svm/sev.c | 5 +++++ > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h > index f0dea3750ca9..59516ad2028b 100644 > --- a/arch/x86/include/asm/svm.h > +++ b/arch/x86/include/asm/svm.h > @@ -158,7 +158,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area { > u64 avic_physical_id; /* Offset 0xf8 */ > u8 reserved_7[8]; > u64 vmsa_pa; /* Used for an SEV-ES guest */ > - u8 reserved_8[720]; > + u8 reserved_8[40]; > + u64 allowed_sev_features; /* Offset 0x138 */ > + u8 reserved_9[672]; > /* > * Offset 0x3e0, 32 bytes reserved > * for use by hypervisor/software. > @@ -294,6 +296,8 @@ static_assert((X2AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == X2AVIC_ > (SVM_SEV_FEAT_RESTRICTED_INJECTION | \ > SVM_SEV_FEAT_ALTERNATE_INJECTION) > > +#define VMCB_ALLOWED_SEV_FEATURES_VALID BIT_ULL(63) > + > struct vmcb_seg { > u16 selector; > u16 attrib; > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index a16c873b3232..d12b4d615b32 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -899,6 +899,7 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm) > static int __sev_launch_update_vmsa(struct kvm *kvm, struct kvm_vcpu *vcpu, > int *error) > { > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > struct sev_data_launch_update_vmsa vmsa; > struct vcpu_svm *svm = to_svm(vcpu); > int ret; > @@ -908,6 +909,10 @@ static int __sev_launch_update_vmsa(struct kvm *kvm, struct kvm_vcpu *vcpu, > return -EINVAL; > } > > + if (cpu_feature_enabled(X86_FEATURE_ALLOWED_SEV_FEATURES)) > + svm->vmcb->control.allowed_sev_features = VMCB_ALLOWED_SEV_FEATURES_VALID | > + sev->vmsa_features; > + > /* Perform some pre-encryption checks against the VMSA */ > ret = sev_es_sync_vmsa(svm); > if (ret)
