51 lines
1.8 KiB
Diff
51 lines
1.8 KiB
Diff
From 36046b3119eb2338c811f43b2956c3aa787a2e3c Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
|
|
Date: Tue, 10 Jun 2025 13:37:07 +0100
|
|
Subject: [PATCH 29/31] hw/ufs/lu: skip automatic zero-init of large array
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
|
|
RH-MergeRequest: 461: Solve -ftrivial-auto-var-init performance regression with QEMU_UNINITIALIZED
|
|
RH-Jira: RHEL-99887
|
|
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
RH-Commit: [28/30] 4d68ab4596b8fb97106d07e5af11dc3fdcb25e96
|
|
|
|
The 'ufs_emulate_scsi_cmd' method has a 4k byte array used for
|
|
copying data from the device. Skip the automatic zero-init of
|
|
this array to eliminate the performance overhead in the I/O hot
|
|
path.
|
|
|
|
The 'outbuf' array will be fully initialized when data is copied
|
|
from the guest.
|
|
|
|
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
|
|
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
|
|
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
|
|
Message-id: 20250610123709.835102-30-berrange@redhat.com
|
|
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
(cherry picked from commit 7708e298180550eac262c1fd742e6e80c711a5d8)
|
|
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
|
|
---
|
|
hw/ufs/lu.c | 2 +-
|
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
|
|
|
diff --git a/hw/ufs/lu.c b/hw/ufs/lu.c
|
|
index 81bfff9b4e..caad82dcc4 100644
|
|
--- a/hw/ufs/lu.c
|
|
+++ b/hw/ufs/lu.c
|
|
@@ -194,7 +194,7 @@ static int ufs_emulate_wlun_inquiry(UfsRequest *req, uint8_t *outbuf,
|
|
static UfsReqResult ufs_emulate_scsi_cmd(UfsLu *lu, UfsRequest *req)
|
|
{
|
|
uint8_t lun = lu->lun;
|
|
- uint8_t outbuf[4096];
|
|
+ QEMU_UNINITIALIZED uint8_t outbuf[4096];
|
|
uint8_t sense_buf[UFS_SENSE_SIZE];
|
|
uint8_t scsi_status;
|
|
int len = 0;
|
|
--
|
|
2.39.3
|
|
|