linux-kernel - [PATCH 05/11] virt/coco/sev-guest: Carve out the request issuing logic into a helper

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Date:   Thu, 16 Feb 2023 13:41:14 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Dionna Glaze <dionnaglaze@...gle.com>,
        Joerg Roedel <jroedel@...e.de>,
        Michael Roth <michael.roth@....com>,
        Nikunj A Dadhania <nikunj@....com>,
        Peter Gonda <pgonda@...gle.com>,
        Tom Lendacky <Thomas.Lendacky@....com>,
        linux-coco@...ts.linux.dev, x86@...nel.org
Subject: [PATCH 05/11] virt/coco/sev-guest: Carve out the request issuing logic into a helper

From: "Borislav Petkov (AMD)" <bp@...en8.de>

This makes the code flow a lot easier to follow.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
---
 drivers/virt/coco/sev-guest/sev-guest.c | 41 +++++++++++++++----------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index c0ecc5885573..e72289de2b28 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -318,27 +318,12 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
 	return __enc_payload(snp_dev, req, payload, sz);
 }
 
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
-				u8 type, void *req_buf, size_t req_sz, void *resp_buf,
-				u32 resp_sz, __u64 *fw_err)
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
 {
 	unsigned long err, override_err = 0;
 	unsigned int override_npages = 0;
-	u64 seqno;
 	int rc;
 
-	/* Get message sequence and verify that its a non-zero */
-	seqno = snp_get_msg_seqno(snp_dev);
-	if (!seqno)
-		return -EIO;
-
-	memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
-
-	/* Encrypt the userspace provided payload */
-	rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
-	if (rc)
-		return rc;
-
 retry_request:
 	/*
 	 * Call firmware to process the request. In this function the encrypted
@@ -347,7 +332,6 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
 	 * prevent reuse of the IV.
 	 */
 	rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
-
 	switch (rc) {
 	case -ENOSPC:
 		/*
@@ -384,6 +368,29 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
 	if (override_npages)
 		snp_dev->input.data_npages = override_npages;
 
+	return rc;
+}
+
+static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
+				u8 type, void *req_buf, size_t req_sz, void *resp_buf,
+				u32 resp_sz, __u64 *fw_err)
+{
+	u64 seqno;
+	int rc;
+
+	/* Get message sequence and verify that its a non-zero */
+	seqno = snp_get_msg_seqno(snp_dev);
+	if (!seqno)
+		return -EIO;
+
+	memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
+
+	/* Encrypt the userspace provided payload */
+	rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
+	if (rc)
+		return rc;
+
+	rc = __handle_guest_request(snp_dev, exit_code, fw_err);
 	if (rc) {
 		dev_alert(snp_dev->dev,
 			  "Detected error from ASP request. rc: %d, fw_err: %llu\n",
-- 
2.35.1