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. Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> --- arch/x86/kvm/svm/sev.c | 125 +++++++++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 13 ++++ 2 files changed, 138 insertions(+) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 6b7c8287eada..856a6cf99a61 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1741,6 +1741,111 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) return ret; } +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 = {}; + int i, ret; + + data.gctx_paddr = __psp_pa(sev->snp_context); + data.page_type = SNP_PAGE_TYPE_VMSA; + + for (i = 0; i < kvm->created_vcpus; i++) { + struct vcpu_svm *svm = to_svm(kvm->vcpus[i]); + struct rmpupdate e = {}; + + /* 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. */ + e.assigned = 1; + e.immutable = 1; + e.asid = sev->asid; + e.gpa = -1; + e.pagesize = RMP_PG_SIZE_4K; + ret = rmpupdate(virt_to_page(svm->vmsa), &e); + if (ret) + return ret; + + /* Issue the SNP command to encrypt the VMSA */ + data.address = __sme_pa(svm->vmsa); + ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_UPDATE, + &data, &argp->error); + if (ret) { + snp_page_reclaim(virt_to_page(svm->vmsa), RMP_PG_SIZE_4K); + 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 sev_data_snp_launch_finish *data; + void *id_block = NULL, *id_auth = NULL; + struct kvm_sev_snp_launch_finish params; + 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 we finalize 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); + } + + if (params.auth_key_en) { + 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->auth_key_en = 1; + data->id_auth_paddr = __sme_pa(id_auth); + } + + 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 svm_mem_enc_op(struct kvm *kvm, void __user *argp) { struct kvm_sev_cmd sev_cmd; @@ -1836,6 +1941,9 @@ int svm_mem_enc_op(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; @@ -2324,8 +2432,25 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu) if (vcpu->arch.guest_state_protected) sev_flush_guest_memory(svm, svm->vmsa, PAGE_SIZE); + + /* + * If its an SNP guest, then VMSA was added in the RMP entry as a guest owned page. + * Transition the page to hyperivosr state before releasing it back to the system. + */ + if (sev_snp_guest(vcpu->kvm)) { + struct rmpupdate e = {}; + int rc; + + rc = rmpupdate(virt_to_page(svm->vmsa), &e); + if (rc) { + pr_err("Failed to release SNP guest VMSA page (rc %d), leaking it\n", rc); + goto skip_vmsa_free; + } + } + __free_page(virt_to_page(svm->vmsa)); +skip_vmsa_free: if (svm->ghcb_sa_free) kfree(svm->ghcb_sa); } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 8890d5a340be..8db12055b8b9 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1682,6 +1682,7 @@ enum sev_cmd_id { KVM_SEV_SNP_INIT = 255, KVM_SEV_SNP_LAUNCH_START, KVM_SEV_SNP_LAUNCH_UPDATE, + KVM_SEV_SNP_LAUNCH_FINISH, KVM_SEV_NR_MAX, }; @@ -1693,6 +1694,18 @@ struct kvm_sev_cmd { __u32 sev_fd; }; +#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]; +}; + struct kvm_sev_launch_start { __u32 handle; __u32 policy; -- 2.17.1