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  1. 18 12月, 2012 1 次提交
  3. 22 10月, 2012 1 次提交
    • W
      virtio: force vring descriptors to be allocated from lowmem · b92b1b89
      由 Will Deacon 提交于 
      Virtio devices may attempt to add descriptors to a virtqueue from atomic
context using GFP_ATOMIC allocation. This is problematic because such
allocations can fall outside of the lowmem mapping, causing virt_to_phys
to report bogus physical addresses which are subsequently passed to
userspace via the buffers for the virtual device.

This patch masks out __GFP_HIGH and __GFP_HIGHMEM from the requested
flags when allocating descriptors for a virtqueue. If an atomic
allocation is requested and later fails, we will return -ENOSPC which
will be handled by the driver.

Cc: stable@kernel.org
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      b92b1b89
  5. 28 9月, 2012 11 次提交
  7. 20 7月, 2012 1 次提交
  9. 09 7月, 2012 1 次提交
    • M
      virtio-balloon: fix add/get API use · 9c378abc
      由 Michael S. Tsirkin 提交于 
      Since ee7cd898 'virtio: expose added
descriptors immediately.', in virtio balloon virtqueue_get_buf might
now run concurrently with virtqueue_kick.  I audited both and this
seems safe in practice but this is not guaranteed by the API.
Additionally, a spurious interrupt might in theory make
virtqueue_get_buf run in parallel with virtqueue_add_buf, which is
racy.

While we might try to protect against spurious callbacks it's
easier to fix the driver: balloon seems to be the only one
(mis)using the API like this, so let's just fix balloon.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
      9c378abc
  11. 22 5月, 2012 4 次提交
  13. 17 5月, 2012 1 次提交
  15. 15 4月, 2012 2 次提交
  17. 31 3月, 2012 5 次提交
  19. 29 3月, 2012 1 次提交
  21. 01 3月, 2012 1 次提交
    • A
      virtio: balloon: leak / fill balloon across S4 · 4eb05d56
      由 Amit Shah 提交于 
      commit e562966d added support for S4 to
the balloon driver.  The freeze function did nothing to free the pages,
since reclaiming the pages from the host to immediately give them back
(if S4 was successful) seemed wasteful.  Also, if S4 wasn't successful,
the guest would have to re-fill the balloon.  On restore, the pages were
supposed to be marked freed and the free page counters were incremented
to reflect the balloon was totally deflated.

However, this wasn't done right.  The pages that were earlier taken away
from the guest during a balloon inflation operation were just shown as
used pages after a successful restore from S4.  Just a fancy way of
leaking lots of memory.

Instead of trying that, just leak the balloon on freeze and fill it on
restore/thaw paths.  This works properly now.  The optimisation to not
leak can be added later on after a bit of refactoring of the code.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      4eb05d56
  23. 28 1月, 2012 2 次提交
  25. 12 1月, 2012 9 次提交
    • A
      virtio: balloon: Add freeze, restore handlers to support S4 · e562966d
      由 Amit Shah 提交于 
      Handling balloon hibernate / restore is tricky.  If the balloon was
inflated before going into the hibernation state, upon resume, the host
will not have any memory of that.  Any pages that were passed on to the
host earlier would most likely be invalid, and the host will have to
re-balloon to the previous value to get in the pre-hibernate state.

So the only sane thing for the guest to do here is to discard all the
pages that were put in the balloon.  When to discard the pages is the
next question.

One solution is to deflate the balloon just before writing the image to
the disk (in the freeze() PM callback).  However, asking for pages from
the host just to discard them immediately after seems wasteful of
resources.  Hence, it makes sense to do this by just fudging our
counters soon after wakeup.  This means we don't deflate the balloon
before sleep, and also don't put unnecessary pressure on the host.

This also helps in the thaw case: if the freeze fails for whatever
reason, the balloon should continue to remain in the inflated state.
This was tested by issuing 'swapoff -a' and trying to go into the S4
state.  That fails, and the balloon stays inflated, as expected.  Both
the host and the guest are happy.

Finally, in the restore() callback, we empty the list of pages that were
previously given off to the host, add the appropriate number of pages to
the totalram_pages counter, reset the num_pages counter to 0, and
all is fine.

As a last step, delete the vqs on the freeze callback to prepare for
hibernation, and re-create them in the restore and thaw callbacks to
resume normal operation.

The kthread doesn't race with any operations here, since it's frozen
before the freeze() call and is thawed after the thaw() and restore()
callbacks, so we're safe with that.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      e562966d
    • A
      virtio: balloon: Move vq initialization into separate function · be91c33d
      由 Amit Shah 提交于 
      The probe and PM restore functions will share this code.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      be91c33d
    • A
      virtio: pci: add PM notification handlers for restore, freeze, thaw, poweroff · f0fe6f11
      由 Amit Shah 提交于 
      Handle thaw, restore and freeze notifications from the PM core.  Expose
these to individual virtio drivers that can quiesce and resume vq
operations.  For drivers not implementing the thaw() method, use the
restore method instead.

These functions also save device-specific data so that the device can be
put in pre-suspend state after resume, and disable and enable the PCI
device in the freeze and resume functions, respectively.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      f0fe6f11
    • A
      virtio: pci: switch to new PM API · d0775363
      由 Amit Shah 提交于 
      The older PM API doesn't have a way to get notifications on hibernate
events.  Switch to the newer one that gives us those notifications.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      d0775363
    • R
      virtio: add debugging if driver doesn't kick. · e93300b1
      由 Rusty Russell 提交于 
      Under the existing #ifdef DEBUG, check that they don't have more than
1/10 of a second between an add_buf() and a
virtqueue_notify()/virtqueue_kick_prepare() call.

We could get false positives on a really busy system, but good for
development.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      e93300b1
    • R
      virtio: expose added descriptors immediately. · ee7cd898
      由 Rusty Russell 提交于 
      A virtio driver does virtqueue_add_buf() multiple times before finally
calling virtqueue_kick(); previously we only exposed the added buffers
in the virtqueue_kick() call.  This means we don't need a memory
barrier in virtqueue_add_buf(), but it reduces concurrency as the
device (ie. host) can't see the buffers until the kick.

In the unusual (but now possible) case where a driver does add_buf()
and get_buf() without doing a kick, we do need to insert one before
our counter wraps.  Otherwise we could wrap num_added, and later on
not realize that we have passed the marker where we should have
kicked.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      ee7cd898
    • R
      virtio: avoid modulus operation. · 3b720b8c
      由 Rusty Russell 提交于 
      Since we know vq->vring.num is a power of 2, modulus is lazy (it's asserted
in vring_new_virtqueue()).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      3b720b8c
    • R
      virtio: support unlocked queue kick · 41f0377f
      由 Rusty Russell 提交于 
      Based on patch by Christoph for virtio_blk speedup:

	Split virtqueue_kick to be able to do the actual notification
	outside the lock protecting the virtqueue.  This patch was
	originally done by Stefan Hajnoczi, but I can't find the
	original one anymore and had to recreated it from memory.
	Pointers to the original or corrections for the commit message
	are welcome.

Stefan's patch was here:

	https://github.com/stefanha/linux/commit/a6d06644e3a58e57a774e77d7dc34c4a5a2e7496
	http://www.spinics.net/lists/linux-virtualization/msg14616.html

Third time's the charm!
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      41f0377f
    • R
      virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf · f96fde41
      由 Rusty Russell 提交于 
      Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
      f96fde41