KVM: SVM: Add KVM_SEV SEND_START command

The command is used to create an outgoing SEV guest encryption context.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-Id: <2f1686d0164e0f1b3d6a41d620408393e0a48376.1618498113.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 128 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4bf79dbc3eeb..9f5312956d5e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1111,6 +1111,131 @@ e_free:
 	return ret;
 }
 
+/* Userspace wants to query session length. */
+static int
+__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
+				      struct kvm_sev_send_start *params)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_send_start *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+	if (data == NULL)
+		return -ENOMEM;
+
+	data->handle = sev->handle;
+	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+	if (ret < 0)
+		goto out;
+
+	params->session_len = data->session_len;
+	if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
+				sizeof(struct kvm_sev_send_start)))
+		ret = -EFAULT;
+
+out:
+	kfree(data);
+	return ret;
+}
+
+static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_send_start *data;
+	struct kvm_sev_send_start params;
+	void *amd_certs, *session_data;
+	void *pdh_cert, *plat_certs;
+	int ret;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
+				sizeof(struct kvm_sev_send_start)))
+		return -EFAULT;
+
+	/* if session_len is zero, userspace wants to query the session length */
+	if (!params.session_len)
+		return __sev_send_start_query_session_length(kvm, argp,
+				&params);
+
+	/* some sanity checks */
+	if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
+	    !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
+		return -EINVAL;
+
+	/* allocate the memory to hold the session data blob */
+	session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
+	if (!session_data)
+		return -ENOMEM;
+
+	/* copy the certificate blobs from userspace */
+	pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr,
+				params.pdh_cert_len);
+	if (IS_ERR(pdh_cert)) {
+		ret = PTR_ERR(pdh_cert);
+		goto e_free_session;
+	}
+
+	plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
+				params.plat_certs_len);
+	if (IS_ERR(plat_certs)) {
+		ret = PTR_ERR(plat_certs);
+		goto e_free_pdh;
+	}
+
+	amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
+				params.amd_certs_len);
+	if (IS_ERR(amd_certs)) {
+		ret = PTR_ERR(amd_certs);
+		goto e_free_plat_cert;
+	}
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+	if (data == NULL) {
+		ret = -ENOMEM;
+		goto e_free_amd_cert;
+	}
+
+	/* populate the FW SEND_START field with system physical address */
+	data->pdh_cert_address = __psp_pa(pdh_cert);
+	data->pdh_cert_len = params.pdh_cert_len;
+	data->plat_certs_address = __psp_pa(plat_certs);
+	data->plat_certs_len = params.plat_certs_len;
+	data->amd_certs_address = __psp_pa(amd_certs);
+	data->amd_certs_len = params.amd_certs_len;
+	data->session_address = __psp_pa(session_data);
+	data->session_len = params.session_len;
+	data->handle = sev->handle;
+
+	ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+
+	if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
+			session_data, params.session_len)) {
+		ret = -EFAULT;
+		goto e_free;
+	}
+
+	params.policy = data->policy;
+	params.session_len = data->session_len;
+	if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
+				sizeof(struct kvm_sev_send_start)))
+		ret = -EFAULT;
+
+e_free:
+	kfree(data);
+e_free_amd_cert:
+	kfree(amd_certs);
+e_free_plat_cert:
+	kfree(plat_certs);
+e_free_pdh:
+	kfree(pdh_cert);
+e_free_session:
+	kfree(session_data);
+	return ret;
+}
+
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -1173,6 +1298,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_GET_ATTESTATION_REPORT:
 		r = sev_get_attestation_report(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_SEND_START:
+		r = sev_send_start(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;