From fce8afd76e3a4d8c59c92f84f8027569fd7031d0 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Fri, 15 May 2020 12:14:02 +0200
Subject: [PATCH] virtio-mem: Don't rely on implicit compiler padding for
requests
The compiler will add padding after the last member, make that explicit.
The size of a request is always 24 bytes. The size of a response always
10 bytes. Add compile-time checks.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200515101402.16597-1-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/virtio/virtio_mem.c | 3 +++
include/uapi/linux/virtio_mem.h | 3 +++
2 files changed, 6 insertions(+)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 9e523db3bee17..f658fe9149beb 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -1770,6 +1770,9 @@ static int virtio_mem_probe(struct virtio_device *vdev)
struct virtio_mem *vm;
int rc = -EINVAL;
+ BUILD_BUG_ON(sizeof(struct virtio_mem_req) != 24);
+ BUILD_BUG_ON(sizeof(struct virtio_mem_resp) != 10);
+
vdev->priv = vm = kzalloc(sizeof(*vm), GFP_KERNEL);
if (!vm)
return -ENOMEM;
diff --git a/include/uapi/linux/virtio_mem.h b/include/uapi/linux/virtio_mem.h
index e0a9dc7397c34..a455c488a995c 100644
--- a/include/uapi/linux/virtio_mem.h
+++ b/include/uapi/linux/virtio_mem.h
@@ -103,16 +103,19 @@
struct virtio_mem_req_plug {
__virtio64 addr;
__virtio16 nb_blocks;
+ __virtio16 padding[3];
};
struct virtio_mem_req_unplug {
__virtio64 addr;
__virtio16 nb_blocks;
+ __virtio16 padding[3];
};
struct virtio_mem_req_state {
__virtio64 addr;
__virtio16 nb_blocks;
+ __virtio16 padding[3];
};
struct virtio_mem_req {
--
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