[Qemu-devel] [PATCH] hw/block/fdc: floppy command FIFO memory initialization

From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
To: qemu-devel@nongnu.org, qemu-block@nongnu.org
Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, mreitz@redhat.com,
	andrey.shinkevich@virtuozzo.com, den@openvz.org,
	jsnow@redhat.com
Subject: [Qemu-devel] [PATCH] hw/block/fdc: floppy command FIFO memory initialization
Date: Wed, 29 May 2019 15:22:04 +0300	[thread overview]
Message-ID: <1559132524-228613-1-git-send-email-andrey.shinkevich@virtuozzo.com> (raw)

The uninitialized memory allocated for the command FIFO of the
floppy controller during the VM hardware initialization incurs
many unwanted reports by Valgrind when VM state is being saved.
That verbosity hardens a search for the real memory issues when
the iotests run. Particularly, the patch eliminates 20 unnecessary
reports of the Valgrind tool in the iotest #169.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 hw/block/fdc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 6f19f12..54e470c 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2647,6 +2647,10 @@ static void fdctrl_realize_common(DeviceState *dev, FDCtrl *fdctrl,
 
     FLOPPY_DPRINTF("init controller\n");
     fdctrl->fifo = qemu_memalign(512, FD_SECTOR_LEN);
+    if (fdctrl->fifo) {
+        /* To avoid using the uninitialized memory while saving VM state */
+        memset(fdctrl->fifo, 0, FD_SECTOR_LEN);
+    }
     fdctrl->fifo_size = 512;
     fdctrl->result_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                              fdctrl_result_timer, fdctrl);
-- 
1.8.3.1


