A bad implementation of virtio might cause us to mark the virtqueue
broken: we'll dev_err() in that case, and the device is useless, but
let's not BUG().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

When adding or removing 100G from a balloon:

    BUG: soft lockup - CPU#0 stuck for 22s! [vballoon:367]

We have a wait_event_interruptible(), but the condition is always true
(more ballooning to do) so we don't ever sleep.  We also have a
wait_event() for the host to ack, but that is also always true as QEMU
is synchronous for balloon operations.

Reported-by: Gopesh Kumar Chaudhary <gopchaud@in.ibm.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Pull virtio update from Rusty Russell:
 "A few simple fixes.  Quiet cycle"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  drivers: virtio: Mark function virtballoon_migratepage() as static in virtio_balloon.c
  virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze
  virtio: pci: remove unnecessary pci_set_drvdata()

Mark the function virtballoon_migratepage() as static in
virtio_balloon.c because it is not used outside this file.

This eliminates the following warning in virtio_balloon.c:
drivers/virtio/virtio_balloon.c:372:5: warning: no previous prototype for ‘virtballoon_migratepage’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

According to the virtio spec, the device configuration field
that should be updated after an inflation or deflation
operation is the 'actual' field, not the 'num_pages' one.

Commit 855e0c5288177bcb193f6f6316952d2490478e1c swapped them
in update_balloon_size(). Fix it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: 855e0c5288177bcb193f6f6316952d2490478e1c

This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Pull virtio updates from Rusty Russell:
 "No real surprises"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MAINTAINERS: add tools/virtio/ under virtio
  tools/virtio: move module license stub to module.h
  virtio: include asm/barrier explicitly
  virtio: VIRTIO_F_ANY_LAYOUT feature
  lguest: fix example launcher compilation for broken glibc headers.
  virtio-net: fix the race between channels setting and refill
  tools/lguest: real barriers.
  tools/lguest: fix missing rmb().
  virtio_balloon: leak_balloon(): only tell host if we got pages deflated
  virtio-pci: fix leaks of msix_affinity_masks
  Fix comment typo "CONFIG_PAE"

Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages.  And change code which directly adjusts totalram_pages to
use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.

Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.

This patch also fixes two bugs:

1) enhances virtio_balloon driver to adjust totalhigh_pages when
   reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
   memory.

We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.

[akpm@linux-foundation.org: remove ifdef, per Wanpeng Li, virtio_balloon.c cleanup, per Sergei]
[akpm@linux-foundation.org: export adjust_managed_page_count() to modules, for drivers/virtio/virtio_balloon.c]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

balloon_page_dequeue() can return NULL.  If it does for the first page
being freed then leak_balloon() will create a scatter list with len=0.
Which in turn seems to generate an invalid virtio request.

I didn't get this in practice, I found it by code review.  On the other
hand, such an invalid virtio request will cause errors in QEMU and
fill_balloon() also performs the same check implemented by this commit.

This bug was introduced in e2250429.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # 3.9