diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index f422f9c58ba7..8c54ea84bc57 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -41,7 +41,7 @@ struct snp_guest_dev {
 	struct device *dev;
 	struct miscdevice misc;
 
-	void *certs_data;
+	u8 (*certs_data)[SEV_FW_BLOB_MAX_SIZE];
 	struct snp_guest_crypto *crypto;
 	struct snp_guest_msg *request, *response;
 	struct snp_secrets_page_layout *layout;
@@ -67,8 +67,27 @@ static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
 	return true;
 }
 
+/*
+ * If we receive an error from the host or ASP we have two options. We can
+ * either retry the exact same encrypted request or we can discontinue using the
+ * VMPCK.
+ *
+ * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
+ * encrypt the requests. The IV for this scheme is the sequence number. GCM
+ * cannot tolerate IV reuse.
+ *
+ * The ASP FW v1.51 only increments the sequence numbers on a successful
+ * guest<->ASP back and forth and only accepts messages at its exact sequence
+ * number.
+ *
+ * So if we were to reuse the sequence number the encryption scheme is
+ * vulnerable. If we encrypt the sequence number for a fresh IV the ASP will
+ * reject our request.
+ */
 static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
 {
+	dev_alert(snp_dev->dev, "Disabling vmpck_id: %d to prevent IV reuse.\n",
+		  vmpck_id);
 	memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
 	snp_dev->vmpck = NULL;
 }
@@ -326,29 +345,29 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
 	if (fw_err)
 		*fw_err = err;
 
-	if (rc)
-		return rc;
+	if (rc) {
+		dev_alert(snp_dev->dev,
+			  "Detected error from ASP request. rc: %d, fw_err: %llu\n",
+			  rc, *fw_err);
+		goto disable_vmpck;
+	}
 
-	/*
-	 * The verify_and_dec_payload() will fail only if the hypervisor is
-	 * actively modifying the message header or corrupting the encrypted payload.
-	 * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
-	 * the key cannot be used for any communication. The key is disabled to ensure
-	 * that AES-GCM does not use the same IV while encrypting the request payload.
-	 */
 	rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
 	if (rc) {
 		dev_alert(snp_dev->dev,
-			  "Detected unexpected decode failure, disabling the vmpck_id %d\n",
-			  vmpck_id);
-		snp_disable_vmpck(snp_dev);
-		return rc;
+			  "Detected unexpected decode failure from ASP. rc: %d\n",
+			  rc);
+		goto disable_vmpck;
 	}
 
 	/* Increment to new message sequence after payload decryption was successful. */
 	snp_inc_msg_seqno(snp_dev);
 
 	return 0;
+
+disable_vmpck:
+	snp_disable_vmpck(snp_dev);
+	return rc;
 }
 
 static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
@@ -437,7 +456,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
 	struct snp_ext_report_req req;
 	struct snp_report_resp *resp;
-	int ret, npages = 0, resp_len;
+	int ret, resp_len, req_cert_len, resp_cert_len;
 
 	lockdep_assert_held(&snp_cmd_mutex);
 
@@ -448,14 +467,15 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 		return -EFAULT;
 
 	/* userspace does not want certificate data */
-	if (!req.certs_len || !req.certs_address)
+	req_cert_len = req.certs_len;
+	if (!req_cert_len || !req.certs_address)
 		goto cmd;
 
-	if (req.certs_len > SEV_FW_BLOB_MAX_SIZE ||
-	    !IS_ALIGNED(req.certs_len, PAGE_SIZE))
+	if (req_cert_len > sizeof(*snp_dev->certs_data) ||
+	    !IS_ALIGNED(req_cert_len, PAGE_SIZE))
 		return -EINVAL;
 
-	if (!access_ok((const void __user *)req.certs_address, req.certs_len))
+	if (!access_ok((const void __user *)req.certs_address, req_cert_len))
 		return -EFAULT;
 
 	/*
@@ -464,8 +484,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 	 * the host. If host does not supply any certs in it, then copy
 	 * zeros to indicate that certificate data was not provided.
 	 */
-	memset(snp_dev->certs_data, 0, req.certs_len);
-	npages = req.certs_len >> PAGE_SHIFT;
+	memset(snp_dev->certs_data, 0, sizeof(*snp_dev->certs_data));
 cmd:
 	/*
 	 * The intermediate response buffer is used while decrypting the
@@ -477,25 +496,37 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
 	if (!resp)
 		return -ENOMEM;
 
-	snp_dev->input.data_npages = npages;
+	snp_dev->input.data_npages = sizeof(*snp_dev->certs_data) >> PAGE_SHIFT;
 	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version,
 				   SNP_MSG_REPORT_REQ, &req.data,
 				   sizeof(req.data), resp->data, resp_len, &arg->fw_err);
 
+	resp_cert_len = snp_dev->input.data_npages << PAGE_SHIFT;
+
 	/* If certs length is invalid then copy the returned length */
 	if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
-		req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+		dev_alert(snp_dev->dev,
+			  "Certificate data from host: %d, Max size allocated by driver: %lu.\n",
+			  resp_cert_len, sizeof(*snp_dev->certs_data));
+		ret = -EFAULT;
+	}
+
+	if (ret)
+		goto e_free;
+
+	/* Pass the actual certificate data size back to userspace */
+	req.certs_len = resp_cert_len;
+	if (resp_cert_len > req_cert_len) {
+		arg->fw_err = SNP_GUEST_REQ_INVALID_LEN;
 
 		if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
 			ret = -EFAULT;
-	}
 
-	if (ret)
 		goto e_free;
+	}
 
-	if (npages &&
-	    copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
-			 req.certs_len)) {
+	if (copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
+			 resp_cert_len)) {
 		ret = -EFAULT;
 		goto e_free;
 	}
@@ -676,7 +707,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	if (!snp_dev->response)
 		goto e_free_request;
 
-	snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE);
+	snp_dev->certs_data = alloc_shared_pages(dev, sizeof(*snp_dev->certs_data));
 	if (!snp_dev->certs_data)
 		goto e_free_response;
 
@@ -703,7 +734,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	return 0;
 
 e_free_cert_data:
-	free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
+	free_shared_pages(snp_dev->certs_data, sizeof(*snp_dev->certs_data));
 e_free_response:
 	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
 e_free_request:
@@ -717,7 +748,7 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
 {
 	struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
 
-	free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
+	free_shared_pages(snp_dev->certs_data, sizeof(*snp_dev->certs_data));
 	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
 	free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
 	deinit_crypto(snp_dev->crypto);
