From: Brijesh Singh <brijesh.singh@xxxxxxx> The KVM_SEV_SNP_LAUNCH_FINISH finalize the cryptographic digest and stores it as the measurement of the guest at launch. While finalizing the launch flow, it also issues the LAUNCH_UPDATE command to encrypt the VMSA pages. If its an SNP guest, then VMSA was added in the RMP entry as a guest owned page and also removed from the kernel direct map so flush it later after it is transitioned back to hypervisor state and restored in the direct map. Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> Signed-off-by: Harald Hoyer <harald@xxxxxxxxxxx> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> Signed-off-by: Michael Roth <michael.roth@xxxxxxx> --- .../virt/kvm/x86/amd-memory-encryption.rst | 23 ++++ arch/x86/kvm/svm/sev.c | 122 ++++++++++++++++++ include/uapi/linux/kvm.h | 14 ++ 3 files changed, 159 insertions(+) diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index c94be8e6d657..dafb0c9984f1 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -513,6 +513,29 @@ Returns: 0 on success, -negative on error See the SEV-SNP spec for further details on how to build the VMPL permission mask and page type. +21. KVM_SNP_LAUNCH_FINISH +------------------------- + +After completion of the SNP guest launch flow, the KVM_SNP_LAUNCH_FINISH command can be +issued to make the guest ready for the execution. + +Parameters (in): struct kvm_sev_snp_launch_finish + +Returns: 0 on success, -negative on error + +:: + + struct kvm_sev_snp_launch_finish { + __u64 id_block_uaddr; + __u64 id_auth_uaddr; + __u8 id_block_en; + __u8 auth_key_en; + __u8 host_data[32]; + __u8 pad[6]; + }; + + +See SEV-SNP specification for further details on launch finish input parameters. References ========== diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 03dd227f6090..515e22d0dc30 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2280,6 +2280,109 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) snp_launch_update_gfn_handler, argp); } +static int snp_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct sev_data_snp_launch_update data = {}; + struct kvm_vcpu *vcpu; + unsigned long i; + int ret; + + data.gctx_paddr = __psp_pa(sev->snp_context); + data.page_type = SNP_PAGE_TYPE_VMSA; + + kvm_for_each_vcpu(i, vcpu, kvm) { + struct vcpu_svm *svm = to_svm(vcpu); + u64 pfn = __pa(svm->sev_es.vmsa) >> PAGE_SHIFT; + + /* Perform some pre-encryption checks against the VMSA */ + ret = sev_es_sync_vmsa(svm); + if (ret) + return ret; + + /* Transition the VMSA page to a firmware state. */ + ret = rmp_make_private(pfn, -1, PG_LEVEL_4K, sev->asid, true); + if (ret) + return ret; + + /* Issue the SNP command to encrypt the VMSA */ + data.address = __sme_pa(svm->sev_es.vmsa); + ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_UPDATE, + &data, &argp->error); + if (ret) { + snp_page_reclaim(pfn); + return ret; + } + + svm->vcpu.arch.guest_state_protected = true; + } + + return 0; +} + +static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct kvm_sev_snp_launch_finish params; + struct sev_data_snp_launch_finish *data; + void *id_block = NULL, *id_auth = NULL; + int ret; + + if (!sev_snp_guest(kvm)) + return -ENOTTY; + + if (!sev->snp_context) + return -EINVAL; + + if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params))) + return -EFAULT; + + /* Measure all vCPUs using LAUNCH_UPDATE before finalizing the launch flow. */ + ret = snp_launch_update_vmsa(kvm, argp); + if (ret) + return ret; + + data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT); + if (!data) + return -ENOMEM; + + if (params.id_block_en) { + id_block = psp_copy_user_blob(params.id_block_uaddr, KVM_SEV_SNP_ID_BLOCK_SIZE); + if (IS_ERR(id_block)) { + ret = PTR_ERR(id_block); + goto e_free; + } + + data->id_block_en = 1; + data->id_block_paddr = __sme_pa(id_block); + + id_auth = psp_copy_user_blob(params.id_auth_uaddr, KVM_SEV_SNP_ID_AUTH_SIZE); + if (IS_ERR(id_auth)) { + ret = PTR_ERR(id_auth); + goto e_free_id_block; + } + + data->id_auth_paddr = __sme_pa(id_auth); + + if (params.auth_key_en) + data->auth_key_en = 1; + } + + memcpy(data->host_data, params.host_data, KVM_SEV_SNP_FINISH_DATA_SIZE); + data->gctx_paddr = __psp_pa(sev->snp_context); + ret = sev_issue_cmd(kvm, SEV_CMD_SNP_LAUNCH_FINISH, data, &argp->error); + + kfree(id_auth); + +e_free_id_block: + kfree(id_block); + +e_free: + kfree(data); + + return ret; +} + int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) { struct kvm_sev_cmd sev_cmd; @@ -2376,6 +2479,9 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) case KVM_SEV_SNP_LAUNCH_UPDATE: r = snp_launch_update(kvm, &sev_cmd); break; + case KVM_SEV_SNP_LAUNCH_FINISH: + r = snp_launch_finish(kvm, &sev_cmd); + break; default: r = -EINVAL; goto out; @@ -2831,11 +2937,27 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu) svm = to_svm(vcpu); + /* + * If its an SNP guest, then VMSA was added in the RMP entry as + * a guest owned page. Transition the page to hypervisor state + * before releasing it back to the system. + * Also the page is removed from the kernel direct map, so flush it + * later after it is transitioned back to hypervisor state and + * restored in the direct map. + */ + if (sev_snp_guest(vcpu->kvm)) { + u64 pfn = __pa(svm->sev_es.vmsa) >> PAGE_SHIFT; + + if (host_rmp_make_shared(pfn, PG_LEVEL_4K, true)) + goto skip_vmsa_free; + } + if (vcpu->arch.guest_state_protected) sev_flush_encrypted_page(vcpu, svm->sev_es.vmsa); __free_page(virt_to_page(svm->sev_es.vmsa)); +skip_vmsa_free: if (svm->sev_es.ghcb_sa_free) kvfree(svm->sev_es.ghcb_sa); } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 4098bba17aa4..2bab08a5b5d7 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1921,6 +1921,7 @@ enum sev_cmd_id { KVM_SEV_SNP_INIT, KVM_SEV_SNP_LAUNCH_START, KVM_SEV_SNP_LAUNCH_UPDATE, + KVM_SEV_SNP_LAUNCH_FINISH, KVM_SEV_NR_MAX, }; @@ -2055,6 +2056,19 @@ struct kvm_sev_snp_launch_update { __u8 vmpl1_perms; }; +#define KVM_SEV_SNP_ID_BLOCK_SIZE 96 +#define KVM_SEV_SNP_ID_AUTH_SIZE 4096 +#define KVM_SEV_SNP_FINISH_DATA_SIZE 32 + +struct kvm_sev_snp_launch_finish { + __u64 id_block_uaddr; + __u64 id_auth_uaddr; + __u8 id_block_en; + __u8 auth_key_en; + __u8 host_data[KVM_SEV_SNP_FINISH_DATA_SIZE]; + __u8 pad[6]; +}; + #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) -- 2.25.1