From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Michael S . Tsirkin" <mst@redhat.com>,
David Hildenbrand <david@redhat.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
teawater <teawaterz@linux.alibaba.com>
Subject: [PATCH v4 16/15] virtio-mem: Don't rely on implicit compiler padding for requests
Date: Fri, 15 May 2020 12:14:02 +0200 [thread overview]
Message-ID: <20200515101402.16597-1-david@redhat.com> (raw)
In-Reply-To: <20200507140139.17083-1-david@redhat.com>
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>
---
Something I noticed while working on the spec (which proves that writing a
virtio-spec makes sense :) ).
---
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 9e523db3bee1..f658fe9149be 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 e0a9dc7397c3..a455c488a995 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 {
--
2.25.4
next prev parent reply other threads:[~2020-05-15 10:14 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 14:01 [PATCH v4 00/15] virtio-mem: paravirtualized memory David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 01/15] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 02/15] MAINTAINERS: Add myself as virtio-mem maintainer David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 03/15] virtio-mem: Allow to specify an ACPI PXM as nid David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 04/15] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 05/15] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 06/15] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 07/15] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 08/15] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 09/15] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 10/15] virtio-mem: Better retry handling David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 11/15] virtio-mem: Add parent resource for all added "System RAM" David Hildenbrand
2020-05-07 14:06 ` Pankaj Gupta
2020-05-07 14:01 ` [PATCH v4 12/15] virtio-mem: Drop manual check for already present memory David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 13/15] virtio-mem: Unplug subblocks right-to-left David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 14/15] virtio-mem: Use -ETXTBSY as error code if the device is busy David Hildenbrand
2020-05-07 14:01 ` [PATCH v4 15/15] virtio-mem: Try to unplug the complete online memory block first David Hildenbrand
2020-05-15 10:14 ` David Hildenbrand [this message]
2020-05-20 5:25 ` [PATCH v4 00/15] virtio-mem: paravirtualized memory teawater
2020-05-20 7:56 ` David Hildenbrand
2020-06-02 7:09 ` David Hildenbrand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200515101402.16597-1-david@redhat.com \
--to=david@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mst@redhat.com \
--cc=pankaj.gupta.linux@gmail.com \
--cc=teawaterz@linux.alibaba.com \
--cc=virtio-dev@lists.oasis-open.org \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).