[Qemu-devel] [PULL 26/71] block/nvme: Remove QEMU_PACKED from naturally aligned NVMeRegs struct

Kevin Wolf posted 71 patches 6 years, 2 months ago
Maintainers: Eric Blake <eblake@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Ronnie Sahlberg <ronniesahlberg@gmail.com>, Alberto Garcia <berto@igalia.com>, Kevin Wolf <kwolf@redhat.com>, Cleber Rosa <crosa@redhat.com>, Peter Lieven <pl@kamp.de>, Wen Congyang <wencongyang2@huawei.com>, Jeff Cody <codyprime@gmail.com>, Xie Changlong <xiechanglong.d@gmail.com>, Markus Armbruster <armbru@redhat.com>, Liu Yuan <namei.unix@gmail.com>, "Daniel P. Berrangé" <berrange@redhat.com>, John Snow <jsnow@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <fam@euphon.net>, "Michael S. Tsirkin" <mst@redhat.com>, Ari Sundholm <ari@tuxera.com>, "Richard W.M. Jones" <rjones@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, Max Reitz <mreitz@redhat.com>, Josh Durgin <jdurgin@redhat.com>
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[Qemu-devel] [PULL 26/71] block/nvme: Remove QEMU_PACKED from naturally aligned NVMeRegs struct
Posted by Kevin Wolf 6 years, 2 months ago
From: Thomas Huth <thuth@redhat.com>

The QEMU_PACKED is causing a compiler warning/error with GCC 9:

  CC      block/nvme.o
block/nvme.c: In function ‘nvme_create_queue_pair’:
block/nvme.c:209:22: error: taking address of packed member of
 ‘struct <anonymous>’ may result in an unaligned pointer value
 [-Werror=address-of-packed-member]
  209 |     q->sq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale];

All members of the struct are naturally aligned, so there should
not be the need for QEMU_PACKED here, and the following QEMU_BUILD_BUG_ON
also ensures that there is no padding. Thus simply remove the QEMU_PACKED
here.

Buglink: https://bugs.launchpad.net/qemu/+bug/1817525
Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/nvme.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/nvme.c b/block/nvme.c
index b5952c9b08..6c2ce7dfa5 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -82,7 +82,7 @@ typedef volatile struct {
     uint8_t  reserved1[0xec0];
     uint8_t  cmd_set_specfic[0x100];
     uint32_t doorbells[];
-} QEMU_PACKED NVMeRegs;
+} NVMeRegs;
 
 QEMU_BUILD_BUG_ON(offsetof(NVMeRegs, doorbells) != 0x1000);
 
-- 
2.20.1