[PATCH 6/6] KVM: SVM: Add support for KVM_SEV_GM_VERIFY_DIGEST command

[Hao Feng]

The command is used to send guest owner's key digest to SEV firmware,
firmware will check the key digest to see if the key negotiation is
successful or not.

Signed-off-by: Hao Feng <fenghao@xxxxxxxx>
Signed-off-by: Pu Wen <puwen@xxxxxxxx>
---
 arch/x86/kvm/svm.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f8e7042..4dbdccf 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -7015,6 +7015,50 @@ static int sev_gm_get_digest(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return ret;
 }
 
+static int sev_gm_verify_digest(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	void __user *digest = (void __user *)(uintptr_t)argp->data;
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_gm_verify_digest *data = NULL;
+	struct kvm_sev_gm_verify_digest params;
+	void *digest_blob = NULL;
+	int *error = &argp->error;
+	int ret;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, digest, sizeof(params)))
+		return -EFAULT;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (params.uaddr) {
+		digest_blob = psp_copy_user_blob(params.uaddr, params.len);
+		if (IS_ERR(digest_blob)) {
+			ret = PTR_ERR(digest_blob);
+			goto e_free;
+		}
+
+		data->address = __psp_pa(digest_blob);
+		data->len = params.len;
+	}
+
+	data->handle = sev->handle;
+	ret = sev_issue_cmd(kvm, SEV_CMD_GM_VERIFY_DIGEST, data, error);
+	if (ret)
+		goto e_free_digest;
+
+e_free_digest:
+	kfree(digest_blob);
+e_free:
+	kfree(data);
+
+	return ret;
+}
+
 static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -7059,6 +7103,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_GM_GET_DIGEST:
 		r = sev_gm_get_digest(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_GM_VERIFY_DIGEST:
+		r = sev_gm_verify_digest(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
-- 
2.7.4