linux-kernel - [PATCH v2 2/4] x86/sev: Allocate request in TSC_INFO

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Message-ID: <20250611040842.2667262-3-aik@amd.com>
Date: Wed, 11 Jun 2025 14:08:40 +1000
From: Alexey Kardashevskiy <aik@....com>
To: <x86@...nel.org>
CC: <linux-kernel@...r.kernel.org>, Thomas Gleixner <tglx@...utronix.de>,
	"Ingo Molnar" <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen
	<dave.hansen@...ux.intel.com>, "H. Peter Anvin" <hpa@...or.com>, Tom Lendacky
	<thomas.lendacky@....com>, Nikunj A Dadhania <nikunj@....com>, Ard Biesheuvel
	<ardb@...nel.org>, Ashish Kalra <ashish.kalra@....com>, Dionna Glaze
	<dionnaglaze@...gle.com>, Michael Roth <michael.roth@....com>, "Kuppuswamy
 Sathyanarayanan" <sathyanarayanan.kuppuswamy@...ux.intel.com>, "Alexey
 Kardashevskiy" <aik@....com>
Subject: [PATCH v2 2/4] x86/sev: Allocate request in TSC_INFO_REQ on stack

Allocate a 88 byte request structure on stack and skip needless
kzalloc/kfree.

While at this, correct indent.

No functional change intended.

Reviewed-by: Tom Lendacky <thomas.lendacky@....com>
Reviewed-by: Dionna Glaze <dionnaglaze@...gle.com>
Signed-off-by: Alexey Kardashevskiy <aik@....com>
---
 arch/x86/coco/sev/core.c | 30 ++++++++------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index cf91cb4e2c47..068653865bfb 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -2069,7 +2069,7 @@ static int __init snp_get_tsc_info(void)
 	struct snp_tsc_info_resp *tsc_resp;
 	struct snp_tsc_info_req *tsc_req;
 	struct snp_msg_desc *mdesc;
-	struct snp_guest_req *req;
+	struct snp_guest_req req = {};
 	int rc = -ENOMEM;
 
 	tsc_req = kzalloc(sizeof(*tsc_req), GFP_KERNEL);
@@ -2085,28 +2085,24 @@ static int __init snp_get_tsc_info(void)
 	if (!tsc_resp)
 		goto e_free_tsc_req;
 
-	req = kzalloc(sizeof(*req), GFP_KERNEL);
-	if (!req)
-		goto e_free_tsc_resp;
-
 	mdesc = snp_msg_alloc();
 	if (IS_ERR_OR_NULL(mdesc))
-		goto e_free_req;
+		goto e_free_tsc_resp;
 
 	rc = snp_msg_init(mdesc, snp_vmpl);
 	if (rc)
 		goto e_free_mdesc;
 
-	req->msg_version = MSG_HDR_VER;
-	req->msg_type = SNP_MSG_TSC_INFO_REQ;
-	req->vmpck_id = snp_vmpl;
-	req->req_buf = tsc_req;
-	req->req_sz = sizeof(*tsc_req);
-	req->resp_buf = (void *)tsc_resp;
-	req->resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN;
-	req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+	req.msg_version = MSG_HDR_VER;
+	req.msg_type = SNP_MSG_TSC_INFO_REQ;
+	req.vmpck_id = snp_vmpl;
+	req.req_buf = tsc_req;
+	req.req_sz = sizeof(*tsc_req);
+	req.resp_buf = (void *)tsc_resp;
+	req.resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN;
+	req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
 
-	rc = snp_send_guest_request(mdesc, req);
+	rc = snp_send_guest_request(mdesc, &req);
 	if (rc)
 		goto e_request;
 
@@ -2127,9 +2123,7 @@ static int __init snp_get_tsc_info(void)
 	memzero_explicit(tsc_resp, sizeof(*tsc_resp) + AUTHTAG_LEN);
 e_free_mdesc:
 	snp_msg_free(mdesc);
-e_free_req:
-	kfree(req);
- e_free_tsc_resp:
+e_free_tsc_resp:
 	kfree(tsc_resp);
 e_free_tsc_req:
 	kfree(tsc_req);
-- 
2.49.0