Commit Graph

211 Commits

Author SHA1 Message Date
Rusty Russell
98e8c6bc66 virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
Now noone relies on this behavior, we simplify virtqueue_add_buf() so it
return 0 or -errno.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
2012-12-18 15:20:34 +10:30
Rusty Russell
06ca287dba virtio: move queue_index and num_free fields into core struct virtqueue.
They're generic concepts, so hoist them.  This also avoids accessor
functions (though kept around for merge with DaveM's net tree).

This goes even further than Jason Wang's 17bb6d4088 patch
("virtio-ring: move queue_index to vring_virtqueue") which moved the
queue_index from the specific transport.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:31 +10:30
Wei Yongjun
1ce6853aa0 virtio-pci: use module_pci_driver to simplify the code
Use the module_pci_driver() macro to make the code simpler
by eliminating module_init and module_exit calls.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:30 +10:30
Rafael Aquini
e22504296d virtio_balloon: introduce migration primitives to balloon pages
Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a guest,
thus imposing performance penalties associated with the reduced number of
transparent huge pages that could be used by the guest workload.

Besides making balloon pages movable at allocation time and introducing
the necessary primitives to perform balloon page migration/compaction,
this patch also introduces the following locking scheme, in order to
enhance the syncronization methods for accessing elements of struct
virtio_balloon, thus providing protection against concurrent access
introduced by parallel memory migration threads.

 - balloon_lock (mutex) : synchronizes the access demand to elements of
                          struct virtio_balloon and its queue operations;

[yongjun_wei@trendmicro.com.cn: fix missing unlock on error in fill_balloon()]
[akpm@linux-foundation.org: avoid having multiple return points in fill_balloon()]
[akpm@linux-foundation.org: fix printk warning]Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:27 -08:00
Cornelia Huck
237242bddc virtio: Don't access index after unregister.
Virtio wants to release used indices after the corresponding
virtio device has been unregistered. However, virtio does not
hold an extra reference, giving up its last reference with
device_unregister(), making accessing dev->index afterwards
invalid.

I actually saw problems when testing my (not-yet-merged)
virtio-ccw code:

- device_add virtio-net,id=xxx
-> creates device virtio<n> with n>0

- device_del xxx
-> deletes virtio<n>, but calls ida_simple_remove with an
   index of 0

- device_add virtio-net,id=xxx
-> tries to add virtio0, which is still in use...

So let's save the index we want to release before calling
device_unregister().

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-11-09 14:54:24 +10:30
Will Deacon
b92b1b89a3 virtio: force vring descriptors to be allocated from lowmem
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: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-22 18:19:49 +10:30
Brian Foley
d78b519f6b virtio_mmio: Don't attempt to create empty virtqueues
If a virtio device reports a QueueNumMax of 0, vring_new_virtqueue()
doesn't check this, and thanks to an unsigned (i < num - 1) loop
guard, scribbles over memory when initialising the free list.

Avoid by not trying to create zero-descriptor queues, as there's no
way to do any I/O with one.

Signed-off-by: Brian Foley <brian.foley@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:16 +09:30
Brian Foley
3850d29fc4 virtio_mmio: fix off by one error allocating queue
vm_setup_vq fails to allow VirtQueues needing only 2 pages of
storage, as it should. Found with a kernel using 64kB pages, but
can be provoked if a virtio device reports QueueNumMax where the
descriptor table and available ring fit in one page, and the used
ring on the second (<= 227 descriptors with 4kB pages and <= 3640
with 64kB pages.)

Signed-off-by: Brian Foley <brian.foley@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:16 +09:30
Peter Senna Tschudin
74a74b376c drivers/virtio/virtio_pci.c: fix error return code
Convert a nonnegative error return code to a negative one, as returned
elsewhere in the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// </smpl>

Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:16 +09:30
Michael S. Tsirkin
5543a6ac31 virtio: don't crash when device is buggy
Because of a sanity check in virtio_dev_remove, a buggy device can crash
kernel.  And in case of rproc it's userspace so it's not a good idea.
We are unloading a driver so how bad can it be?
Be less aggressive in handling this error: if it's a driver bug,
warning once should be enough.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:16 +09:30
Rusty Russell
eccbb05a64 virtio: remove CONFIG_VIRTIO_RING
Everyone who selects VIRTIO is also made to select VIRTIO_RING; just make
them synonymous, since we removed the indirection layer some time ago.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:15 +09:30
Rusty Russell
387daf1716 virtio: add help to CONFIG_VIRTIO option.
Trying to enable a virtio driver (eg CONFIG_VIRTIO_BLK) is painful
because it depends on CONFIG_VIRTIO.  CONFIG_VIRTIO doesn't tell you
how to turn it on (it's selected from anything which provides a virtio
bus).

This patch at least adds some documentation, visible in menuconfig, as
a hint.

Reported-by: Kent Overstreet <koverstreet@google.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:15 +09:30
Michael S. Tsirkin
6457f126c8 virtio: support reserved vqs
virtio network device multiqueue support reserves
vq 3 for future use (useful both for future extensions and to make it
pretty - this way receive vqs have even and transmit - odd numbers).
Make it possible to skip initialization for
specific vq numbers by specifying NULL for name.
Document this usage as well as (existing) NULL callback.

Drivers using this not coded up yet, so I simply tested
with virtio-pci and verified that this patch does
not break existing drivers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:15 +09:30
Jason Wang
75a0a52be3 virtio: introduce an API to set affinity for a virtqueue
Sometimes, virtio device need to configure irq affinity hint to maximize the
performance. Instead of just exposing the irq of a virtqueue, this patch
introduce an API to set the affinity for a virtqueue.

The api is best-effort, the affinity hint may not be set as expected due to
platform support, irq sharing or irq type. Currently, only pci method were
implemented and we set the affinity according to:

- if device uses INTX, we just ignore the request
- if device has per vq vector, we force the affinity hint
- if the virtqueues share MSI, make the affinity OR over all affinities
  requested

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:15 +09:30
Jason Wang
17bb6d4088 virtio-ring: move queue_index to vring_virtqueue
Instead of storing the queue index in transport-specific virtio structs,
this patch moves them to vring_virtqueue and introduces an helper to get
the value.  This lets drivers simplify their management and tracing of
virtqueues.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:15 +09:30
Rusty Russell
7a23eb28fa virtio_balloon: not EXPERIMENTAL any more.
It is not experimental in any vaguely-sane sense.

Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:14 +09:30
Michael S. Tsirkin
04679f34c1 virtio-balloon: dependency fix
Devices should depend on virtio, not select it.  It's supposed to be
selected by the particular driver, e.g. VIRTIO_PCI.
Make balloon depend on VIRTIO and EXPERIMENTAL
(to match description).

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:14 +09:30
Nicholas Bellinger
59057fbc37 [SCSI] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN scanning
This patch changes virtio-scsi to use a new virtio_driver->scan() callback
so that scsi_scan_host() can be properly invoked once virtio_dev_probe() has
set add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK) to signal active virtio-ring
operation, instead of from within virtscsi_probe().

This fixes a bug where SCSI LUN scanning for both virtio-scsi-raw and
virtio-scsi/tcm_vhost setups was happening before VIRTIO_CONFIG_S_DRIVER_OK
had been set, causing VIRTIO_SCSI_S_BAD_TARGET to occur.  This fixes a bug
with virtio-scsi/tcm_vhost where LUN scan was not detecting LUNs.

Tested with virtio-scsi-raw + virtio-scsi/tcm_vhost w/ IBLOCK on 3.5-rc2 code.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20 08:59:03 +01:00
Michael S. Tsirkin
9c378abc5c virtio-balloon: fix add/get API use
Since ee7cd8981e '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: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
2012-07-09 09:07:22 +09:30
Pawel Moll
81a054ce0b virtio-mmio: Devices parameter parsing
This patch adds an option to instantiate guest virtio-mmio devices
basing on a kernel command line (or module) parameter, for example:

	virtio_mmio.devices=0x100@0x100b0000:48

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:15 +09:30
Asias He
90e03207f4 virtio: Use ida to allocate virtio index
Current index allocation in virtio is based on a monotonically
increasing variable "index". This means we'll run out of numbers
after a while. E.g. someone crazy doing this in host side.

while(1) {
	hot-plug a virtio device
	hot-unplug the virito devcie
}

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:12 +09:30
Amit Shah
c877bab507 virtio: balloon: separate out common code between remove and freeze functions
The remove and freeze functions have a lot of shared code; put it into a
common function that gets called by both.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:11 +09:30
Amit Shah
c45b4166d9 virtio: balloon: drop restore_common()
restore_common() was used when there were different thaw and freeze PM
callbacks implemented.  We removed thaw in commit
f38f8387cb.

restore_common() can be removed and virtballoon_restore() can itself do
the restore ops.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:11 +09:30
Amit Shah
b8ae0eb320 virtio: balloon: let host know of updated balloon size before module removal
When the balloon module is removed, we deflate the balloon, reclaiming
all the pages that were given to the host.  However, we don't update the
config values for the new balloon size, resulting in the host showing
outdated balloon values.

The size update is done after each leak and fill operation, only the
module removal case was left out.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-05-17 12:14:34 +03:00
Michael S. Tsirkin
3ccc9372ed virtio_balloon: fix handling of PAGE_SIZE != 4k
As reported by David Gibson, current code handles PAGE_SIZE != 4k
completely wrong which can lead to guest memory corruption errors:

- page_to_balloon_pfn is wrong: e.g. on system with 64K page size
 it gives the same pfn value for 16 different pages.

- we also need to convert back to linux pfns when we free.

- for each linux page we need to tell host about multiple balloon
  pages, but code only adds one pfn to the array.

This patch fixes all that, tested with a 64k ppc64 kernel.

Reported-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 11:51:06 +03:00
David Gibson
1a87228f5f virtio_balloon: Fix endian bug
Although virtio config space fields are usually in guest-native endian,
the spec for the virtio balloon device explicitly states that both fields
in its config space are little-endian.

However, the current virtio_balloon driver does not have a suitable endian
swap for the 'num_pages' field, although it does have one for the 'actual'
field.  This patch corrects the bug, adding sparse annotation while we're
at it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 11:51:05 +03:00
Amit Shah
f878d0be22 virtio-pci: switch to PM ops macro to initialise PM functions
Use the SET_SYSTEM_SLEEP_PM_OPS macro to initialise the suspend/resume
functions in the new PM API.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:51 +05:30
Amit Shah
04c2322bee virtio-pci: S3 support
There's no difference in supporting S3 and S4 for virtio devices: the
vqs have to be re-created as the device has to be assumed to be reset at
restore-time.  Since S4 already handles this situation, we can directly
use the same code and callbacks for S3 support.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:51 +05:30
Amit Shah
0517fdd156 virtio-pci: drop restore_common()
restore_common() was shared between restore and thaw callbacks.  With
thaw gone, we don't need restore_common() anymore.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:51 +05:30
Amit Shah
f38f8387cb virtio: drop thaw PM operation
The thaw operation was used by the balloon driver, but after the last
commit there's no reason to have separate thaw and restore callbacks.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:50 +05:30
Amit Shah
e47d854e57 virtio: balloon: Allow stats update after restore from S4
There's no reason stats update after restore can't work.  If a host
requested for stats, and before servicing the request, the guest entered
S4, upon restore, the stats request can still be processed and sent off
to the host.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:50 +05:30
David Howells
9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Amit Shah
4eb05d562e virtio: balloon: leak / fill balloon across S4
commit e562966dba 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-03-01 09:28:41 +10:30
Jason Wang
a72caae218 virtio: correct the memory barrier in virtqueue_kick_prepare()
Use virtio_mb() to make sure the available index to be exposed before
checking the the avail event. Otherwise we may get stale value of
avail event in guest and never kick the host after.

Note: this fixes a bug introduced by ee7cd8981e.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2012-01-28 08:10:23 +10:30
Jason Wang
4dbc5d9f4f virtio: fix typos of memory barriers
Note: this fixes a bug introduced recently in
7b21e34fd1.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-28 08:10:22 +10:30
Amit Shah
e562966dba virtio: balloon: Add freeze, restore handlers to support S4
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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:47 +10:30
Amit Shah
be91c33dd1 virtio: balloon: Move vq initialization into separate function
The probe and PM restore functions will share this code.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:46 +10:30
Amit Shah
f0fe6f1150 virtio: pci: add PM notification handlers for restore, freeze, thaw, poweroff
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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:44 +10:30
Amit Shah
d077536386 virtio: pci: switch to new PM API
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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:44 +10:30
Rusty Russell
e93300b1af virtio: add debugging if driver doesn't kick.
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: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:43 +10:30
Rusty Russell
ee7cd8981e virtio: expose added descriptors immediately.
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: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:43 +10:30
Rusty Russell
3b720b8c86 virtio: avoid modulus operation.
Since we know vq->vring.num is a power of 2, modulus is lazy (it's asserted
in vring_new_virtqueue()).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:43 +10:30
Rusty Russell
41f0377f73 virtio: support unlocked queue kick
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:

	a6d06644e3
	http://www.spinics.net/lists/linux-virtualization/msg14616.html

Third time's the charm!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:43 +10:30
Rusty Russell
f96fde41f7 virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf
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: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2012-01-12 15:44:42 +10:30
Rusty Russell
5dfc17628d virtio: document functions better.
The old documentation is left over from when we used a structure with
strategy pointers.

And move the documentation to the C file as per kernel practice.
Though I disagree...

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2012-01-12 15:44:42 +10:30
Sasha Levin
1e214a5c1a virtio-balloon: Trivial cleanups
Trivial changes to remove forgotten junk, format comments, and correct names.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:42 +10:30
Rusty Russell
7b21e34fd1 virtio: harsher barriers for rpmsg.
We were cheating with our barriers; using the smp ones rather than the
real device ones.  That was fine, until rpmsg came along, which is
used to talk to a real device (a non-SMP CPU).

Unfortunately, just putting back the real barriers (reverting
d57ed95d) causes a performance regression on virtio-pci.  In
particular, Amos reports netbench's TCP_RR over virtio_net CPU
utilization increased up to 35% while throughput went down by up to
14%.

By comparison, this branch is in the noise.

Reference: https://lkml.org/lkml/2011/12/11/22

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:42 +10:30
David S. Miller
b3613118eb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2011-12-02 13:49:21 -05:00
Michael S. Tsirkin
e6af578c53 virtio-pci: make reset operation safer
virtio pci device reset actually just does an I/O
write, which in PCI is really posted, that is it
can complete on CPU before the device has received it.

Further, interrupts might have been pending on
another CPU, so device callback might get invoked after reset.

This conflicts with how drivers use reset, which is typically:
	reset
	unregister
a callback running after reset completed can race with
unregister, potentially leading to use after free bugs.

Fix by flushing out the write, and flushing pending interrupts.

This assumes that device is never reset from
its vq/config callbacks, or in parallel with being
added/removed, document this assumption.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-24 13:04:48 +10:30
Sasha Levin
fe1a7fe2c4 virtio-mmio: Correct the name of the guest features selector
Guest features selector spelling mistake.

Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-24 13:04:47 +10:30
Heiko Carstens
bd20817f73 virtio: add HAS_IOMEM dependency to MMIO platform bus driver
Fix this compile error on s390:

  CC [M]  drivers/virtio/virtio_mmio.o
drivers/virtio/virtio_mmio.c: In function 'vm_get_features':
drivers/virtio/virtio_mmio.c:107:2: error: implicit declaration of function 'writel'

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-24 13:04:47 +10:30
David S. Miller
efd0bf97de Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
The forcedeth changes had a conflict with the conversion over
to atomic u64 statistics in net-next.

The libertas cfg.c code had a conflict with the bss reference
counting fix by John Linville in net-next.

Conflicts:
	drivers/net/ethernet/nvidia/forcedeth.c
	drivers/net/wireless/libertas/cfg.c
2011-11-21 13:50:33 -05:00
Rick Jones
66846048f5 enable virtio_net to return bus_info in ethtool -i consistent with emulated NICs
Add a new .bus_name to virtio_config_ops then modify virtio_net to
call through to it in an ethtool .get_drvinfo routine to report
bus_info in ethtool -i output which is consistent with other
emulated NICs and the output of lspci.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-16 17:26:46 -05:00
Michael S. Tsirkin
72103bd128 virtio-pci: fix use after free
Commit 31a3ddda16 introduced
a use after free in virtio-pci. The main issue is
that the release method signals removal of the virtio device,
while remove signals removal of the pci device.

For example, on driver removal or hot-unplug,
virtio_pci_release_dev is called before virtio_pci_remove.
We then might get a crash as virtio_pci_remove tries to use the
device freed by virtio_pci_release_dev.

We allocate/free all resources together with the
pci device, so we can leave the release method empty.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2011-11-14 11:16:26 +10:30
Linus Torvalds
32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Pawel Moll
edfd52e636 virtio: Add platform bus driver for memory mapped virtio device
This patch, based on virtio PCI driver, adds support for memory
mapped (platform) virtio device. This should allow environments
like qemu to use virtio-based block & network devices even on
platforms without PCI support.

One can define and register a platform device which resources
will describe memory mapped control registers and "mailbox"
interrupt. Such device can be also instantiated using the Device
Tree node with compatible property equal "virtio,mmio".

Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Michael S.Tsirkin <mst@redhat.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:01 +10:30
Krishna Kumar
005b20a8e0 virtio: Dont add "config" to list for !per_vq_vector
For the MSI but non-per_vq_vector case, the config/change vq
also gets added to the list of vqs that need to process the
MSI interrupt. This is not needed as config has it's own
handler (vp_config_changed). In any case, vring_interrupt()
finds nothing needs to be done on this vq.

I tested this patch by testing the "Fallback:" and "Finally
fall back" cases in vp_find_vqs(). Please review.

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:01 +10:30
Paul Gortmaker
b5a2c4f199 virtio: Add module.h to drivers/virtio users.
Up to now, the module.h header was as hard to keep out as
sunlight.  But we are cleaning that up.  Fix the virtio users
who simply expect module.h to be there in every C file.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:32:14 -04:00
Rick Jones
8f9f4668b3 Add ethtool -g support to virtio_net
Add support for reporting ring sizes via ethtool -g to the virtio_net
driver.

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-24 02:07:21 -04:00
Ohad Ben-Cohen
e72542191c virtio: expose for non-virtualization users too
virtio has been so far used only in the context of virtualization,
and the virtio Kconfig was sourced directly by the relevant arch
Kconfigs when VIRTUALIZATION was selected.

Now that we start using virtio for inter-processor communications,
we need to source the virtio Kconfig outside of the virtualization
scope too.

Moreover, some architectures might use virtio for both virtualization
and inter-processor communications, so directly sourcing virtio
might yield unexpected results due to conflicting selections.

The simple solution offered by this patch is to always source virtio's
Kconfig in drivers/Kconfig, and remove it from the appropriate arch
Kconfigs. Additionally, a virtio menu entry has been added so virtio
drivers don't show up in the general drivers menu.

This way anyone can use virtio, though it's arguably less accessible
(and neat!) for virtualization users now.

Note: some architectures (mips and sh) seem to have a VIRTUALIZATION
menu merely for sourcing virtio's Kconfig, so that menu is removed too.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-07-23 16:20:30 +09:30
Michael S. Tsirkin
7ab358c23c virtio: add api for delayed callbacks
Add an API that tells the other side that callbacks
should be delayed until a lot of work has been done.
Implement using the new event_idx feature.

Note: it might seem advantageous to let the drivers
ask for a callback after a specific capacity has
been reached. However, as a single head can
free many entries in the descriptor table,
we don't really have a clue about capacity
until get_buf is called. The API is the simplest
to implement at the moment, we'll see what kind of
hints drivers can pass when there's more than one
user of the feature.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30 11:14:16 +09:30
Michael S. Tsirkin
a5c262c5fd virtio_ring: support event idx feature
Support for the new event idx feature:
1. When enabling interrupts, publish the current avail index
   value to the host to get interrupts on the next update.
2. Use the new avail_event feature to reduce the number
   of exits from the guest.

Simple test with the simulator:

[virtio]# time ./virtio_test
spurious wakeus: 0x7

real    0m0.169s
user    0m0.140s
sys     0m0.019s
[virtio]# time ./virtio_test --no-event-idx
spurious wakeus: 0x11

real    0m0.649s
user    0m0.295s
sys     0m0.335s

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30 11:14:15 +09:30
Dave Hansen
bf50e69f63 virtio balloon: kill tell-host-first logic
The virtio balloon driver has a VIRTIO_BALLOON_F_MUST_TELL_HOST
feature bit.  Whenever the bit is set, the guest kernel must
always tell the host before we free pages back to the allocator.
Without this feature, we might free a page (and have another
user touch it) while the hypervisor is unprepared for it.

But, if the bit is _not_ set, we are under no obligation to
reverse the order; we're under no obligation to do _anything_.
As of now, qemu-kvm defines the bit, but doesn't set it.

This patch makes the "tell host first" logic the only case.  This
should make everybody happy, and reduce the amount of untested or
untestable code in the kernel.

This _also_ means that we don't have to preserve a pfn list
after the pages are freed, which should let us get rid of some
temporary storage (vb->pfns) eventually.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30 11:14:13 +09:30
Amit Shah
31a3ddda16 virtio_pci: Prevent double-free of pci regions after device hot-unplug
In the case where a virtio-console port is in use (opened by a program)
and a virtio-console device is removed, the port is kept around but all
the virtio-related state is assumed to be gone.

When the port is finally released (close() called), we call
device_destroy() on the port's device.  This results in the parent
device's structures to be freed as well.  This includes the PCI regions
for the virtio-console PCI device.

Once this is done, however, virtio_pci_release_dev() kicks in, as the
last ref to the virtio device is now gone, and attempts to do

     pci_iounmap(pci_dev, vp_dev->ioaddr);
     pci_release_regions(pci_dev);
     pci_disable_device(pci_dev);

which results in a double-free warning.

Move the code that releases regions, etc., to the virtio_pci_remove()
function, and all that's now left in release_dev is the final freeing of
the vp_dev.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-04-21 22:57:00 +09:30
Amit Shah
b3258ff1d6 virtio: Decrement avail idx on buffer detach
When detaching a buffer from a vq, the avail.idx value should be
decremented as well.

This was noticed by hot-unplugging a virtio console port and then
plugging in a new one on the same number (re-using the vqs which were
just 'disowned').  qemu reported

   'Guest moved used index from 0 to 256'

when any IO was attempted on the new port.

CC: stable@kernel.org
Reported-by: juzhang <juzhang@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-04-21 22:57:00 +09:30
Milton Miller
8b3bb3ecf1 virtio: remove virtio-pci root device
We sometimes need to map between the virtio device and
the given pci device. One such use is OS installer that
gets the boot pci device from BIOS and needs to
find the relevant block device. Since it can't,
installation fails.

Instead of creating a top-level devices/virtio-pci
directory, create each device under the corresponding
pci device node.  Symlinks to all virtio-pci
devices can be found under the pci driver link in
bus/pci/drivers/virtio-pci/devices, and all virtio
devices under drivers/bus/virtio/devices.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gleb Natapov <gleb@redhat.com>
Tested-by: "Daniel P. Berrange" <berrange@redhat.com>
Cc: stable@kernel.org
2011-01-20 21:37:30 +10:30
Stephen Hemminger
be6528b2e5 virtio: fix format of sysfs driver/vendor files
The sysfs files for virtio produce the wrong format and are missing
the required newline. The output for virtio bus vendor/device should
have the same format as the corresponding entries for PCI devices.

Although this technically changes the ABI for sysfs, these files were
broken to start with!

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-11-24 15:21:12 +10:30
Michael S. Tsirkin
7ae4b866f8 virtio: return correct capacity to users
We can't rely on indirect buffers for capacity
calculations because they need a memory allocation
which might fail.  In particular, virtio_net can get
into this situation under stress, and it drops packets
and performs badly.

So return the number of buffers we can guarantee users.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reported-By: Krishna Kumar2 <krkumar2@in.ibm.com>
2010-11-24 15:21:11 +10:30
Michael S. Tsirkin
1fe9b6fef1 virtio: fix oops on OOM
virtio ring was changed to return an error code on OOM,
but one caller was missed and still checks for vq->vring.num.
The fix is just to check for <0 error code.

Long term it might make sense to change goto add_head to
just return an error on oom instead, but let's apply
a minimal fix for 2.6.35.

Reported-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Chris Mason <chris.mason@oracle.com>
Cc: stable@kernel.org # .34.x
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-26 08:05:31 -07:00
Michael S. Tsirkin
b03214d559 virtio-pci: disable msi at startup
virtio-pci resets the device at startup by writing to the status
register, but this does not clear the pci config space,
specifically msi enable status which affects register
layout.

This breaks things like kdump when they try to use e.g. virtio-blk.

Fix by forcing msi off at startup. Since pci.c already has
a routine to do this, we export and use it instead of duplicating code.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2010-06-23 22:49:07 +09:30
Michael S. Tsirkin
686d363786 virtio: return ENOMEM on out of memory
add_buf returns ring size on out of memory,
this is not what devices expect.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # .34.x
2010-06-23 22:49:06 +09:30
Linus Torvalds
1756ac3d3c Merge branch 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus
* 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (27 commits)
  drivers/char: Eliminate use after free
  virtio: console: Accept console size along with resize control message
  virtio: console: Store each console's size in the console structure
  virtio: console: Resize console port 0 on config intr only if multiport is off
  virtio: console: Add support for nonblocking write()s
  virtio: console: Rename wait_is_over() to will_read_block()
  virtio: console: Don't always create a port 0 if using multiport
  virtio: console: Use a control message to add ports
  virtio: console: Move code around for future patches
  virtio: console: Remove config work handler
  virtio: console: Don't call hvc_remove() on unplugging console ports
  virtio: console: Return -EPIPE to hvc_console if we lost the connection
  virtio: console: Let host know of port or device add failures
  virtio: console: Add a __send_control_msg() that can send messages without a valid port
  virtio: Revert "virtio: disable multiport console support."
  virtio: add_buf_gfp
  trans_virtio: use virtqueue_xxx wrappers
  virtio-rng: use virtqueue_xxx wrappers
  virtio_ring: remove a level of indirection
  virtio_net: use virtqueue_xxx wrappers
  ...

Fix up conflicts in drivers/net/virtio_net.c due to new virtqueue_xxx
wrappers changes conflicting with some other cleanups.
2010-05-21 17:22:52 -07:00
Michael S. Tsirkin
bbd603efb4 virtio: add_buf_gfp
Add an add_buf variant that gets gfp parameter. Use that
to allocate indirect buffers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19 22:15:46 +09:30
Michael S. Tsirkin
7c5e9ed0c8 virtio_ring: remove a level of indirection
We have a single virtqueue_ops implementation,
and it seems unlikely we'll get another one
at this point. So let's remove an unnecessary
level of indirection: it would be very easy to
re-add it if another implementation surfaces.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19 22:15:43 +09:30
Michael S. Tsirkin
946cfe0e05 virtio_balloon: use virtqueue_xxx wrappers
Switch virtio_balloon to new virtqueue_xxx wrappers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19 22:15:41 +09:30
Jiri Kosina
6c9468e9eb Merge branch 'master' into for-next 2010-04-23 02:08:44 +02:00
Balbir Singh
61fb06cc8e virtio: Fix GFP flags passed from the virtio balloon driver
The virtio balloon driver can dig into the reservation pools of the OS
to satisfy a balloon request.  This is not advisable and other balloon
drivers (drivers/xen/balloon.c) avoid this as well.

The patch also adds changes to avoid printing a warning if allocation
fails, since we retry after sometime anyway.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: kvm <kvm@vger.kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-22 07:34:05 -07:00
Tejun Heo
5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Thomas Weber
8839316121 Fix typos in comments
[Ss]ytem => [Ss]ystem
udpate => update
paramters => parameters
orginal => original

Signed-off-by: Thomas Weber <swirl@gmx.li>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-03-16 11:47:56 +01:00
Michael S. Tsirkin
bc505f3739 virtio: set pci bus master enable bit
As all virtio devices perform DMA, we
must enable bus mastering for them to be
spec compliant.

This patch fixes hotplug of virtio devices
with Linux guests and qemu 0.11-0.12.

Tested-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-03-02 13:41:14 +02:00
Michael S. Tsirkin
3119815912 virtio: fix out of range array access
I have observed the following error on virtio-net module unload:

------------[ cut here ]------------
WARNING: at kernel/irq/manage.c:858 __free_irq+0xa0/0x14c()
Hardware name: Bochs
Trying to free already-free IRQ 0
Modules linked in: virtio_net(-) virtio_blk virtio_pci virtio_ring
virtio af_packet e1000 shpchp aacraid uhci_hcd ohci_hcd ehci_hcd [last
unloaded: scsi_wait_scan]
Pid: 1957, comm: rmmod Not tainted 2.6.33-rc8-vhost #24
Call Trace:
 [<ffffffff8103e195>] warn_slowpath_common+0x7c/0x94
 [<ffffffff8103e204>] warn_slowpath_fmt+0x41/0x43
 [<ffffffff810a7a36>] ? __free_pages+0x5a/0x70
 [<ffffffff8107cc00>] __free_irq+0xa0/0x14c
 [<ffffffff8107cceb>] free_irq+0x3f/0x65
 [<ffffffffa0081424>] vp_del_vqs+0x81/0xb1 [virtio_pci]
 [<ffffffffa0091d29>] virtnet_remove+0xda/0x10b [virtio_net]
 [<ffffffffa0075200>] virtio_dev_remove+0x22/0x4a [virtio]
 [<ffffffff812709ee>] __device_release_driver+0x66/0xac
 [<ffffffff81270ab7>] driver_detach+0x83/0xa9
 [<ffffffff8126fc66>] bus_remove_driver+0x91/0xb4
 [<ffffffff81270fcf>] driver_unregister+0x6c/0x74
 [<ffffffffa0075418>] unregister_virtio_driver+0xe/0x10 [virtio]
 [<ffffffffa0091c4d>] fini+0x15/0x17 [virtio_net]
 [<ffffffff8106997b>] sys_delete_module+0x1c3/0x230
 [<ffffffff81007465>] ? old_ich_force_enable_hpet+0x117/0x164
 [<ffffffff813bb720>] ? do_page_fault+0x29c/0x2cc
 [<ffffffff81028e58>] sysenter_dispatch+0x7/0x27
---[ end trace 15e88e4c576cc62b ]---

The bug is in virtio-pci: we use msix_vector as array index to get irq
entry, but some vqs do not have a dedicated vector so this causes an out
of bounds access.  By chance, we seem to often get 0 value, which
results in this error.

Fix by verifying that vector is legal before using it as index.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
Acked-by: Shirley Ma <xma@us.ibm.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
2010-02-28 20:39:11 +02:00
Amit Shah
3b8706240e virtio: Initialize vq->data entries to NULL
vq operations depend on vq->data[i] being NULL to figure out if the vq
entry is in use (since the previous patch).

We have to initialize them to NULL to ensure we don't work with junk
data and trigger false BUG_ONs.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Shirley Ma <xma@us.ibm.com>
2010-02-24 14:22:29 +10:30
Shirley Ma
c021eac414 virtio: Add ability to detach unused buffers from vrings
There's currently no way for a virtio driver to ask for unused
buffers, so it has to keep a list itself to reclaim them at shutdown.
This is redundant, since virtio_ring stores that information.  So
add a new hook to do this.

Signed-off-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:27 +10:30
Michael S. Tsirkin
d57ed95da4 virtio: use smp_XX barriers on SMP
virtio is communicating with a virtual "device" that actually runs on
another host processor. Thus SMP barriers can be used to control
memory access ordering.

Where possible, we should use SMP barriers which are more lightweight than
mandatory barriers, because mandatory barriers also control MMIO effects on
accesses through relaxed memory I/O windows (which virtio does not use)
(compare specifically smp_rmb and rmb on x86_64).

We can't just use smp_mb and friends though, because
we must force memory ordering even if guest is UP since host could be
running on another CPU, but SMP barriers are defined to barrier() in
that configuration. So, for UP fall back to mandatory barriers instead.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:25 +10:30
Rusty Russell
97a545ab6c virtio: remove bogus barriers from DEBUG version of virtio_ring.c
With DEBUG defined, we add an ->in_use flag to detect if the caller
invokes two virtio methods in parallel.  The barriers attempt to ensure
timely update of the ->in_use flag.

But they're voodoo: if we need these barriers it implies that the
calling code doesn't have sufficient synchronization to ensure the
code paths aren't invoked at the same time anyway, and we want to
detect it.

Also, adding barriers changes timing, so turning on debug has more
chance of hiding real problems.

Thanks to MST for drawing my attention to this code...

CC: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:24 +10:30
Rusty Russell
169c246a30 virtio: fix balloon without VIRTIO_BALLOON_F_STATS_VQ
When running under qemu-kvm-0.11.0:

	BUG: unable to handle kernel paging request at 56e58955
	...
	Process vballoon (pid: 1297, ti=c7976000 task=c70a6ca0 task.ti=c7
	...
	Call Trace:
	 [<c88253a3>] ? balloon+0x1b3/0x440 [virtio_balloon]
	 [<c041c2d7>] ? schedule+0x327/0x9d0
	 [<c88251f0>] ? balloon+0x0/0x440 [virtio_balloon]
	 [<c014a2d4>] ? kthread+0x74/0x80
	 [<c014a260>] ? kthread+0x0/0x80
	 [<c0103b36>] ? kernel_thread_helper+0x6/0x30

need_stats_update should be zero-initialized.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Adam Litke <agl@us.ibm.com>
2010-02-24 14:22:17 +10:30
Adam Litke
1f34c71afe virtio: Fix scheduling while atomic in virtio_balloon stats
This is a fix for my earlier patch: "virtio: Add memory statistics reporting to
the balloon driver (V4)".

I discovered that all_vm_events() can sleep and therefore stats collection
cannot be done in interrupt context.  One solution is to handle the interrupt
by noting that stats need to be collected and waking the existing vballoon
kthread which will complete the work via stats_handle_request().  Rusty, is
this a saner way of doing business?

There is one issue that I would like a broader opinion on.  In stats_request, I
update vb->need_stats_update and then wake up the kthread.  The kthread uses
vb->need_stats_update as a condition variable.  Do I need a memory barrier
between the update and wake_up to ensure that my kthread sees the correct
value?  My testing suggests that it is not needed but I would like some
confirmation from the experts.

Signed-off-by: Adam Litke <agl@us.ibm.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:14 +10:30
Adam Litke
9564e138b1 virtio: Add memory statistics reporting to the balloon driver (V4)
Changes since V3:
 - Do not do endian conversions as they will be done in the host
 - Report stats that reference a quantity of memory in bytes
 - Minor coding style updates

Changes since V2:
 - Increase stat field size to 64 bits
 - Report all sizes in kb (not pages)
 - Drop anon_pages stat and fix endianness conversion

Changes since V1:
 - Use a virtqueue instead of the device config space

When using ballooning to manage overcommitted memory on a host, a system for
guests to communicate their memory usage to the host can provide information
that will minimize the impact of ballooning on the guests.  The current method
employs a daemon running in each guest that communicates memory statistics to a
host daemon at a specified time interval.  The host daemon aggregates this
information and inflates and/or deflates balloons according to the level of
host memory pressure.  This approach is effective but overly complex since a
daemon must be installed inside each guest and coordinated to communicate with
the host.  A simpler approach is to collect memory statistics in the virtio
balloon driver and communicate them directly to the hypervisor.

This patch enables the guest-side support by adding stats collection and
reporting to the virtio balloon driver.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (minor fixes)
2010-02-24 14:22:08 +10:30
Jamie Lokier
1f08b833dd Add __devexit_p around reference to virtio_pci_remove
This is needed to compile with CONFIG_VIRTIO_PCI=y,
because virtio_pci_remove is marked __devexit.

Signed-off-by: Jamie Lokier <jamie@shareable.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:04 +10:30
Jeff Mahoney
d817cd5255 virtio: fix section mismatch warnings
Fix fixes the following warnings by renaming the driver structures to be
suffixed with _driver.

WARNING: drivers/virtio/virtio_balloon.o(.data+0x88): Section mismatch in reference from the variable virtio_balloon to the function .devexit.text:virtballoon_remove()

WARNING: drivers/char/hw_random/virtio-rng.o(.data+0x88): Section mismatch in reference from the variable virtio_rng to the function .devexit.text:virtrng_remove()

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:39 -08:00
Michael S. Tsirkin
2d61ba9503 virtio: order used ring after used index read
On SMP guests, reads from the ring might bypass used index reads. This
causes guest crashes because host writes to used index to signal ring
data readiness.  Fix this by inserting rmb before used ring reads.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2009-10-29 08:50:37 +10:30
Michael S. Tsirkin
0b22bd0ba0 virtio-pci: fix per-vq MSI-X request logic
Commit f68d24082e
in 2.6.32-rc1 broke requesting IRQs for per-VQ MSI-X vectors:
- vector number was used instead of the vector itself
- we try to request an IRQ for VQ which does not
  have a callback handler

This is a regression that causes warnings in kernel log,
potentially lower performance as we need to scan vq list,
and might cause system failure if the interrupt
requested is in fact needed by another system.

This was not noticed earlier because in most cases
we were falling back on shared interrupt for all vqs.

The warnings often look like this:

virtio-pci 0000:00:03.0: irq 26 for MSI/MSI-X
virtio-pci 0000:00:03.0: irq 27 for MSI/MSI-X
virtio-pci 0000:00:03.0: irq 28 for MSI/MSI-X
IRQ handler type mismatch for IRQ 1
current handler: i8042
Pid: 2400, comm: modprobe Tainted: G        W
2.6.32-rc3-11952-gf3ed8d8-dirty #1
Call Trace:
 [<ffffffff81072aed>] ? __setup_irq+0x299/0x304
 [<ffffffff81072ff3>] ? request_threaded_irq+0x144/0x1c1
 [<ffffffff813455af>] ? vring_interrupt+0x0/0x30
 [<ffffffff81346598>] ? vp_try_to_find_vqs+0x583/0x5c7
 [<ffffffffa0015188>] ? skb_recv_done+0x0/0x34 [virtio_net]
 [<ffffffff81346609>] ? vp_find_vqs+0x2d/0x83
 [<ffffffff81345d00>] ? vp_get+0x3c/0x4e
 [<ffffffffa0016373>] ? virtnet_probe+0x2f1/0x428 [virtio_net]
 [<ffffffffa0015188>] ? skb_recv_done+0x0/0x34 [virtio_net]
 [<ffffffffa00150d8>] ? skb_xmit_done+0x0/0x39 [virtio_net]
 [<ffffffff8110ab92>] ? sysfs_do_create_link+0xcb/0x116
 [<ffffffff81345cc2>] ? vp_get_status+0x14/0x16
 [<ffffffff81345464>] ? virtio_dev_probe+0xa9/0xc8
 [<ffffffff8122b11c>] ? driver_probe_device+0x8d/0x128
 [<ffffffff8122b206>] ? __driver_attach+0x4f/0x6f
 [<ffffffff8122b1b7>] ? __driver_attach+0x0/0x6f
 [<ffffffff8122a9f9>] ? bus_for_each_dev+0x43/0x74
 [<ffffffff8122a374>] ? bus_add_driver+0xea/0x22d
 [<ffffffff8122b4a3>] ? driver_register+0xa7/0x111
 [<ffffffffa001a000>] ? init+0x0/0xc [virtio_net]
 [<ffffffff81009051>] ? do_one_initcall+0x50/0x148
 [<ffffffff8106e117>] ? sys_init_module+0xc5/0x21a
 [<ffffffff8100af02>] ? system_call_fastpath+0x16/0x1b
virtio-pci 0000:00:03.0: irq 26 for MSI/MSI-X
virtio-pci 0000:00:03.0: irq 27 for MSI/MSI-X

Reported-by: Marcelo Tosatti <mtosatti@redhat.com>
Reported-by: Shirley Ma <xma@us.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-29 08:50:36 +10:30
Uwe Kleine-König
1e65175c2c move virtballoon_remove to .devexit.text
The function virtballoon_remove is used only wrapped by __devexit_p so
define it using __devexit.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-22 16:39:31 +10:30
Christian Borntraeger
e95646c3ec virtio: let header files include virtio_ids.h
Rusty,

commit 3ca4f5ca73
    virtio: add virtio IDs file
moved all device IDs into a single file. While the change itself is
a very good one, it can break userspace applications. For example
if a userspace tool wanted to get the ID of virtio_net it used to
include virtio_net.h. This does no longer work, since virtio_net.h
does not include virtio_ids.h.
This patch moves all "#include <linux/virtio_ids.h>" from the C
files into the header files, making the header files compatible with
the old ones.

In addition, this patch exports virtio_ids.h to userspace.

CC: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-10-22 16:39:28 +10:30
Fernando Luis Vazquez Cao
3ca4f5ca73 virtio: add virtio IDs file
Virtio IDs are spread all over the tree which makes assigning new IDs
bothersome. Putting them together should make the process less error-prone.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-09-23 22:26:32 +09:30
Rusty Russell
3c1b27d504 virtio: make add_buf return capacity remaining
This API change means that virtio_net can tell how much capacity
remains for buffers.  It's necessarily fuzzy, since
VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors
in one, *if* we can kmalloc.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>
2009-09-23 22:26:31 +09:30
Rusty Russell
f68d24082e virtio_pci: minor MSI-X cleanups
1) Rename vp_request_vectors to vp_request_msix_vectors, and take
   non-MSI-X case out to caller.
2) Comment weird pci_enable_msix API
3) Rename vp_find_vq to setup_vq.
4) Fix spaces to tabs
5) Make nvectors calc internal to vp_try_to_find_vqs()
6) Rename vector to msix_vector for more clarity.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
2009-09-23 22:26:31 +09:30
Michael S. Tsirkin
e969fed542 virtio: refactor find_vqs
This refactors find_vqs, making it more readable and robust, and fixing
two regressions from 2.6.30:
- double free_irq causing BUG_ON on device removal
- probe failure when vq can't be assigned to msi-x vector
  (reported on old host kernels)

Tested-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-07-30 16:03:45 +09:30
Michael S. Tsirkin
f6c8250703 virtio: delete vq from list
This makes delete vq the reverse of find vq.
This is required to make it possible to retry find_vqs
after a failure, otherwise the list gets corrupted.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-07-30 16:03:44 +09:30
Michael S. Tsirkin
ff52c3fc71 virtio: fix memory leak on device removal
Make vp_free_vectors do the reverse of vq_request_vectors.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-07-30 16:03:44 +09:30