Go to file
David Hildenbrand 61082ad6a6 virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE
The initial virtio-mem spec states that while unplugged memory should not
be read, the device still has to allow for reading unplugged memory inside
the usable region. The primary motivation for this default handling was
to simplify bringup of virtio-mem, because there were corner cases where
Linux might have accidentially read unplugged memory inside added Linux
memory blocks.

In the meantime, we:
1. Removed /dev/kmem in commit bbcd53c960 ("drivers/char: remove
   /dev/kmem for good")
2. Disallowed access to virtio-mem device memory via /dev/mem in
   commit 2128f4e21a ("virtio-mem: disallow mapping virtio-mem memory via
   /dev/mem")
3. Sanitized access to virtio-mem device memory via /proc/kcore in
   commit 0daa322b8f ("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 ce2814622e ("virtio-mem: kdump mode to sanitize /proc/vmcore
   access")

"Accidential" access to unplugged memory is no longer possible; we can
support the new VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE feature that will be
required by some hypervisors implementing virtio-mem in the near future.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Cc: Hui Zhu <teawater@gmail.com>
Cc: Sebastien Boeuf <sebastien.boeuf@intel.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2021-11-10 15:32:38 +01:00
Documentation Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch dma-mapping updates for Linux 5.16 2021-11-09 10:56:41 -08:00
block for-5.16/drivers-2021-11-09 2021-11-09 11:24:08 -08:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Kbuild updates for v5.16 2021-11-08 09:15:45 -08:00
drivers virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE 2021-11-10 15:32:38 +01:00
fs io_uring-5.16-2021-11-09 2021-11-09 11:11:37 -08:00
include virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE 2021-11-10 15:32:38 +01:00
init Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
ipc ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL 2021-11-09 10:02:53 -08:00
kernel dma-mapping updates for Linux 5.16 2021-11-09 10:56:41 -08:00
lib Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
mm Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
net 9p-for-5.16-rc1: fixes, netfs read support and checkpatch rewrite 2021-11-09 10:30:13 -08:00
samples Add gitignore file for samples/fanotify/ subdirectory 2021-11-07 11:19:24 -08:00
scripts Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
security Merge branch 'akpm' (patches from Andrew) 2021-11-06 14:08:17 -07:00
sound TTY / Serial driver update for 5.16-rc1 2021-11-04 09:09:37 -07:00
tools Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt kvm: irqfd: avoid update unmodified entries of the routing 2021-09-30 04:27:10 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
Makefile Kbuild updates for v5.16 2021-11-08 09:15:45 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.