linux-kernel - [GIT PULL] virtio-mem changes for v5.16

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Date:   Wed, 10 Nov 2021 17:37:54 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        virtualization@...ts.linux-foundation.org,
        "Michael S . Tsirkin" <mst@...hat.com>,
        David Hildenbrand <david@...hat.com>
Subject: [GIT PULL] virtio-mem changes for v5.16

Hi Linus,

usually this would have went via the vhost tree, but as this patch depends
on some patches that just went in via Andrews tree and MST doesn't have
any other patches for this merge window, I'm sending it myself
and base it on current mainline that contains the relevant commits
already. Thanks!

The following changes since commit cb690f5238d71f543f4ce874aa59237cf53a877c:

  Merge tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block (2021-11-09 11:24:08 -0800)

are available in the Git repository at:

  https://github.com/davidhildenbrand/linux.git tags/virtio-mem-for-5.16

for you to fetch changes up to 61082ad6a6e1f999eef7e7e90046486c87933b1e:

  virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE (2021-11-10 15:32:38 +0100)

----------------------------------------------------------------
virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE

Support the VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE feature in virtio-mem, now
that "accidential" access to logically unplugged memory inside added
Linux memory blocks is no longer possible, because we:

1. Removed /dev/kmem in commit bbcd53c96071 ("drivers/char: remove
   /dev/kmem for good")
2. Disallowed access to virtio-mem device memory via /dev/mem in commit
   2128f4e21aa ("virtio-mem: disallow mapping virtio-mem memory via
   /dev/mem")
3. Sanitized access to virtio-mem device memory via /proc/kcore in
   commit 0daa322b8ff9 ("fs/proc/kcore: don't read offline sections,
   logically offline pages and hwpoisoned pages")
4. Sanitized access to virtio-mem device memory via /proc/vmcore in
   commit ce2814622e84 ("virtio-mem: kdump mode to sanitize /proc/vmcore
   access")

The new VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE feature that will be required
by some hypervisors implementing virtio-mem in the near future, so let's
support it now that we safely can.

Signed-off-by: David Hildenbrand <david@...hat.com>

----------------------------------------------------------------
David Hildenbrand (1):
      virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE

 drivers/virtio/virtio_mem.c     | 1 +
 include/uapi/linux/virtio_mem.h | 9 ++++++---
 2 files changed, 7 insertions(+), 3 deletions(-)