From: "Borislav Petkov (AMD)" <bp@alien8.de>

Date: Tue, 7 Mar 2023 09:19:19 -0600

Subject: [PATCH] virt/coco/sev-guest: Carve out the request issuing logic into

 a helper

References: bsc#1012628

Patch-mainline: 6.2.8

Git-commit: 0fdb6cc7c89cb5e0cbc45dbdbafb8e3fb92ddc95

commit 0fdb6cc7c89cb5e0cbc45dbdbafb8e3fb92ddc95 upstream.

This makes the code flow a lot easier to follow.

No functional changes.

  [ Tom: touchups. ]

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>

Link: https://lore.kernel.org/r/20230307192449.24732-6-bp@alien8.de

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 drivers/virt/coco/sev-guest/sev-guest.c | 44 +++++++++++++++----------

 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c

index a51bd4af..07dafe22 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:

 		/*

@@ -401,7 +385,33 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in

 	if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)

 		return -EIO;

+	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) {

+		if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)

+			return rc;

+

 		dev_alert(snp_dev->dev,

 			  "Detected error from ASP request. rc: %d, fw_err: %llu\n",

 			  rc, *fw_err);

-- 

2.35.3