Commit Graph

94 Commits

Author SHA1 Message Date
Jason Wang 87646a348e virtio_ring: allow to store zero as the ctx
Allow zero to be store as a ctx, with this we could store e.g zero
value which could be meaningful for the case of storing headroom
through ctx.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-24 13:37:00 -07:00
Michael S. Tsirkin 5a08b04f63 virtio: allow extra context per descriptor
Allow extra context per descriptor. To avoid slow down for data path,
this disables use of indirect descriptors for this vq.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-05-02 23:41:43 +03:00
Michael S. Tsirkin f94682dde5 virtio: add context flag to find vqs
Allows maintaining extra context per vq.  For ease of use, passing in
NULL is legal and disables the feature for all vqs.

Includes fixes by Christian for s390, acked by Cornelia.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-05-02 23:41:43 +03:00
Michael S. Tsirkin 0d5415b489 Revert "vring: Force use of DMA API for ARM-based systems with legacy devices"
This reverts commit c7070619f3.

This has been shown to regress on some ARM systems:

by forcing on DMA API usage for ARM systems, we have inadvertently
kicked open a hornets' nest in terms of cache-coherency. Namely that
unless the virtio device is explicitly described as capable of coherent
DMA by firmware, the DMA APIs on ARM and other DT-based platforms will
assume it is non-coherent. This turns out to cause a big problem for the
likes of QEMU and kvmtool, which generate virtio-mmio devices in their
guest DTs but neglect to add the often-overlooked "dma-coherent"
property; as a result, we end up with the guest making non-cacheable
accesses to the vring, the host doing so cacheably, both talking past
each other and things going horribly wrong.

We are working on a safer work-around.

Fixes: c7070619f3 ("vring: Force use of DMA API for ARM-based systems with legacy devices")
Reported-by: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
2017-02-03 23:38:50 +02:00
Will Deacon c7070619f3 vring: Force use of DMA API for ARM-based systems with legacy devices
Booting Linux on an ARM fastmodel containing an SMMU emulation results
in an unexpected I/O page fault from the legacy virtio-blk PCI device:

[    1.211721] arm-smmu-v3 2b400000.smmu: event 0x10 received:
[    1.211800] arm-smmu-v3 2b400000.smmu:	0x00000000fffff010
[    1.211880] arm-smmu-v3 2b400000.smmu:	0x0000020800000000
[    1.211959] arm-smmu-v3 2b400000.smmu:	0x00000008fa081002
[    1.212075] arm-smmu-v3 2b400000.smmu:	0x0000000000000000
[    1.212155] arm-smmu-v3 2b400000.smmu: event 0x10 received:
[    1.212234] arm-smmu-v3 2b400000.smmu:	0x00000000fffff010
[    1.212314] arm-smmu-v3 2b400000.smmu:	0x0000020800000000
[    1.212394] arm-smmu-v3 2b400000.smmu:	0x00000008fa081000
[    1.212471] arm-smmu-v3 2b400000.smmu:	0x0000000000000000

<system hangs failing to read partition table>

This is because the legacy virtio-blk device is behind an SMMU, so we
have consequently swizzled its DMA ops and configured the SMMU to
translate accesses. This then requires the vring code to use the DMA API
to establish translations, otherwise all transactions will result in
fatal faults and termination.

Given that ARM-based systems only see an SMMU if one is really present
(the topology is all described by firmware tables such as device-tree or
IORT), then we can safely use the DMA API for all legacy virtio devices.
Modern devices can advertise the prescense of an IOMMU using the
VIRTIO_F_IOMMU_PLATFORM feature flag.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: <stable@vger.kernel.org>
Fixes: 876945dbf6 ("arm64: Hook up IOMMU dma_ops")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
2017-01-25 00:33:11 +02:00
Felipe Franciosi 0c7eaf5930 virtio_ring: fix description of virtqueue_get_buf
The device (not the driver) populates the used ring and includes the len
of how much data was written.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-16 00:13:38 +02:00
Gonglei c60923cb9c virtio_ring: fix complaint by sparse
# make C=2 CF="-D__CHECK_ENDIAN__" ./drivers/virtio/

drivers/virtio/virtio_ring.c:423:19: warning: incorrect type in assignment (different base types)
drivers/virtio/virtio_ring.c:423:19:    expected unsigned int [unsigned] [assigned] i
drivers/virtio/virtio_ring.c:423:19:    got restricted __virtio16 [usertype] next
drivers/virtio/virtio_ring.c:423:19: warning: incorrect type in assignment (different base types)
drivers/virtio/virtio_ring.c:423:19:    expected unsigned int [unsigned] [assigned] i
drivers/virtio/virtio_ring.c:423:19:    got restricted __virtio16 [usertype] next
drivers/virtio/virtio_ring.c:423:19: warning: incorrect type in assignment (different base types)
drivers/virtio/virtio_ring.c:423:19:    expected unsigned int [unsigned] [assigned] i
drivers/virtio/virtio_ring.c:423:19:    got restricted __virtio16 [usertype] next
drivers/virtio/virtio_ring.c:604:39: warning: incorrect type in initializer (different base types)
drivers/virtio/virtio_ring.c:604:39:    expected unsigned short [unsigned] [usertype] nextflag
drivers/virtio/virtio_ring.c:604:39:    got restricted __virtio16
drivers/virtio/virtio_ring.c:612:33: warning: restricted __virtio16 degrades to integer

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-15 06:39:47 +02:00
Michael S. Tsirkin 75bfa81bf0 virtio_ring: mark vring_dma_dev inline
This inline function is unused on configurations
where dma_map/unmap are empty macros.

Make the function inline to avoid gcc errors because
of an unused static function.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-31 00:40:08 +02:00
Ladi Prosek 0ea1e4a6d9 virtio_ring: Make interrupt suppression spec compliant
According to the spec, if the VIRTIO_RING_F_EVENT_IDX feature bit is
negotiated the driver MUST set flags to 0. Not dirtying the available
ring in virtqueue_disable_cb also has a minor positive performance
impact, improving L1 dcache load missed by ~0.5% in vring_bench.

Writes to the used event field (vring_used_event) are still unconditional.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: <stable@vger.kernel.org> # f277ec4 virtio_ring: shadow available
Cc: <stable@vger.kernel.org>
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-31 00:21:40 +02:00
Baoyou Xie af7c1beccf virtio: mark vring_dma_dev() static
We get 1 warning when building kernel with W=1:
drivers/virtio/virtio_ring.c:170:16: warning: no previous prototype for 'vring_dma_dev' [-Wmissing-prototypes]

In fact, this function is only used in the file in which it is
declared and don't need a declaration, but can be made static.
so this patch marks this function with 'static'.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-09-09 21:12:35 +03:00
Michael S. Tsirkin 3cc36f6e34 virtio: fix error handling for debug builds
On error, virtqueue_add calls START_USE but not
END_USE. Thankfully that's normally empty anyway,
but might not be when debugging. Fix it up.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-09 13:42:35 +03:00
Wei Yongjun 58625edf9e virtio: fix memory leak in virtqueue_add()
When using the indirect buffers feature, 'desc' is allocated in
virtqueue_add() but isn't freed before leaving on a ring full error,
causing a memory leak.

For example, it seems rather clear that this can trigger
with virtio net if mergeable buffers are not used.

Cc: stable@vger.kernel.org
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-09 13:42:34 +03:00
Michael S. Tsirkin 1a93769399 virtio: new feature to detect IOMMU device quirk
The interaction between virtio and IOMMUs is messy.

On most systems with virtio, physical addresses match bus addresses,
and it doesn't particularly matter which one we use to program
the device.

On some systems, including Xen and any system with a physical device
that speaks virtio behind a physical IOMMU, we must program the IOMMU
for virtio DMA to work at all.

On other systems, including SPARC and PPC64, virtio-pci devices are
enumerated as though they are behind an IOMMU, but the virtio host
ignores the IOMMU, so we must either pretend that the IOMMU isn't
there or somehow map everything as the identity.

Add a feature bit to detect that quirk: VIRTIO_F_IOMMU_PLATFORM.

Any device with this feature bit set to 0 needs a quirk and has to be
passed physical addresses (as opposed to bus addresses) even though
the device is behind an IOMMU.

Note: it has to be a per-device quirk because for example, there could
be a mix of passed-through and virtual virtio devices. As another
example, some devices could be implemented by an out of process
hypervisor backend (in case of qemu vhost, or vhost-user) and so support
for an IOMMU needs to be coded up separately.

It would be cleanest to handle this in IOMMU core code, but that needs
per-device DMA ops. While we are waiting for that to be implemented, use
a work-around in virtio core.

Note: a "noiommu" feature is a quirk - add a wrapper to make
that clear.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-01 21:44:52 +03:00
Dan Carpenter e00f7bd221 virtio: Silence uninitialized variable warning
Smatch complains that we might not initialize "queue".  The issue is
callers like setup_vq() from virtio_pci_modern.c where "num" could be
something like 2 and "vring_align" is 64.  In that case, vring_size() is
less than PAGE_SIZE.  It won't happen in real life, but we're getting
the value of "num" from a register so it's not really possible to tell
what value it holds with static analysis.

Let's just silence the warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-05-01 15:50:08 +03:00
Andy Lutomirski 78fe398723 vring: Use the DMA API on Xen
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
2016-03-02 17:01:59 +02:00
Andy Lutomirski 2a2d1382fe virtio: Add improved queue allocation API
This leaves vring_new_virtqueue alone for compatbility, but it
adds two new improved APIs:

vring_create_virtqueue: Creates a virtqueue backed by automatically
allocated coherent memory.  (Some day it this could be extended to
support non-coherent memory, too, if there ends up being a platform
on which it's worthwhile.)

__vring_new_virtqueue: Creates a virtqueue with a manually-specified
layout.  This should allow mic_virtio to work much more cleanly.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:01:57 +02:00
Andy Lutomirski 780bc7903a virtio_ring: Support DMA APIs
virtio_ring currently sends the device (usually a hypervisor)
physical addresses of its I/O buffers.  This is okay when DMA
addresses and physical addresses are the same thing, but this isn't
always the case.  For example, this never works on Xen guests, and
it is likely to fail if a physical "virtio" device ever ends up
behind an IOMMU or swiotlb.

The immediate use case for me is to enable virtio on Xen guests.
For that to work, we need vring to support DMA address translation
as well as a corresponding change to virtio_pci or to another
driver.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:01:57 +02:00
Andy Lutomirski d26c96c810 vring: Introduce vring_use_dma_api()
This is a kludge, but no one has come up with a a better idea yet.
We'll introduce DMA API support guarded by vring_use_dma_api().
Eventually we may be able to return true on more and more systems,
and hopefully we can get rid of vring_use_dma_api() entirely some
day.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:01:56 +02:00
Michael S. Tsirkin 788e5b3a5d virtio_ring: use virt_store_mb
We need a full barrier after writing out event index, using
virt_store_mb there seems better than open-coding.  As usual, we need a
wrapper to account for strong barriers.

It's tempting to use this in vhost as well, for that, we'll
need a variant of smp_store_mb that works on __user pointers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-01-12 20:47:02 +02:00
Venkatesh Srinivas f277ec42f3 virtio_ring: shadow available ring flags & index
Improves cacheline transfer flow of available ring header.

Virtqueues are implemented as a pair of rings, one producer->consumer
avail ring and one consumer->producer used ring; preceding the
avail ring in memory are two contiguous u16 fields -- avail->flags
and avail->idx. A producer posts work by writing to avail->idx and
a consumer reads avail->idx.

The flags and idx fields only need to be written by a producer CPU
and only read by a consumer CPU; when the producer and consumer are
running on different CPUs and the virtio_ring code is structured to
only have source writes/sink reads, we can continuously transfer the
avail header cacheline between 'M' states between cores. This flow
optimizes core -> core bandwidth on certain CPUs.

(see: "Software Optimization Guide for AMD Family 15h Processors",
Section 11.6; similar language appears in the 10h guide and should
apply to CPUs w/ exclusive caches, using LLC as a transfer cache)

Unfortunately the existing virtio_ring code issued reads to the
avail->idx and read-modify-writes to avail->flags on the producer.

This change shadows the flags and index fields in producer memory;
the vring code now reads from the shadows and only ever writes to
avail->flags and avail->idx, allowing the cacheline to transfer
core -> core optimally.

In a concurrent version of vring_bench, the time required for
10,000,000 buffer checkout/returns was reduced by ~2% (average
across many runs) on an AMD Piledriver (15h) CPU:

(w/o shadowing):
 Performance counter stats for './vring_bench':
     5,451,082,016      L1-dcache-loads
     ...
       2.221477739 seconds time elapsed

(w/ shadowing):
 Performance counter stats for './vring_bench':
     5,405,701,361      L1-dcache-loads
     ...
       2.168405376 seconds time elapsed

The further away (in a NUMA sense) virtio producers and consumers are
from each other, the more we expect to benefit. Physical implementations
of virtio devices and implementations of virtio where the consumer polls
vring avail indexes (vhost) should also benefit.

Signed-off-by: Venkatesh Srinivas <venkateshs@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-07 17:28:11 +02:00
Michal Hocko 82107539bb virtio: Do not drop __GFP_HIGH in alloc_indirect
b92b1b89a3 ("virtio: force vring descriptors to be allocated from
lowmem") tried to exclude highmem pages for descriptors so it cleared
__GFP_HIGHMEM from a given gfp mask. The patch also cleared __GFP_HIGH
which doesn't make much sense for this fix because __GFP_HIGH only
controls access to memory reserves and it doesn't have any influence
on the zone selection. Some of the call paths use GFP_ATOMIC and
dropping __GFP_HIGH will reduce their changes for success because the
lack of access to memory reserves.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Mel Gorman <mgorman@techsingularity.net>
2015-12-07 17:28:11 +02:00
Tetsuo Handa 5e05bf5833 virtio: Avoid possible kernel panic if DEBUG is enabled.
The virtqueue_add() calls START_USE() upon entry. The virtqueue_kick() is
called if vq->num_added == (1 << 16) - 1 before calling END_USE().
The virtqueue_kick_prepare() called via virtqueue_kick() calls START_USE()
upon entry, and will call panic() if DEBUG is enabled.
Move this virtqueue_kick() call to after END_USE() call.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-02-11 15:03:14 +10:30
Michael S. Tsirkin 43b4f721ce virtio_ring: coding style fix
Most of our code has
struct foo {
}

Fix one instances where ring is inconsistent.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-01-21 16:28:57 +10:30
Michael S. Tsirkin 747ae34a6e virtio: make VIRTIO_F_VERSION_1 a transport bit
Activate VIRTIO_F_VERSION_1 automatically unless legacy_only
is set.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-12-09 12:06:32 +02:00
Cornelia Huck 8906265215 virtio: allow transports to get avail/used addresses
For virtio-1, we can theoretically have a more complex virtqueue
layout with avail and used buffers not on a contiguous memory area
with the descriptor table. For now, it's fine for a transport driver
to stay with the old layout: It needs, however, a way to access
the locations of the avail/used rings so it can register them with
the host.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-12-09 12:05:25 +02:00
Michael S. Tsirkin 00e6f3d9d9 virtio_ring: switch to new memory access APIs
Use virtioXX_to_cpu and friends for access to
all multibyte structures in memory.

Note: this is intentionally mechanical.
A follow-up patch will split long lines etc.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2014-12-09 12:05:25 +02:00
Michael S. Tsirkin e16e12be34 virtio: use u32, not bitmap for features
It seemed like a good idea to use bitmap for features
in struct virtio_device, but it's actually a pain,
and seems to become even more painful when we get more
than 32 feature bits.  Just change it to a u32 for now.

Based on patch by Rusty.

Suggested-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2014-12-09 12:05:23 +02:00
Rusty Russell b25bd2515e virtio_ring: unify direct/indirect code paths.
virtqueue_add() populates the virtqueue descriptor table from the sgs
given.  If it uses an indirect descriptor table, then it puts a single
descriptor in the descriptor table pointing to the kmalloc'ed indirect
table where the sg is populated.

Previously vring_add_indirect() did the allocation and the simple
linear layout.  We replace that with alloc_indirect() which allocates
the indirect table then chains it like the normal descriptor table so
we can reuse the core logic.

This slows down pktgen by less than 1/2 a percent (which uses direct
descriptors), as well as vring_bench, but it's far neater.

vring_bench before:
	1061485790-1104800648(1.08254e+09+/-6.6e+06)ns
vring_bench after:
	1125610268-1183528965(1.14172e+09+/-8e+06)ns

pktgen before:
   787781-796334(793165+/-2.4e+03)pps 365-369(367.5+/-1.2)Mb/sec (365530384-369498976(3.68028e+08+/-1.1e+06)bps) errors: 0

pktgen after:
   779988-790404(786391+/-2.5e+03)pps 361-366(364.35+/-1.3)Mb/sec (361914432-366747456(3.64885e+08+/-1.2e+06)bps) errors: 0

Now, if we make force indirect descriptors by turning off any_header_sg
in virtio_net.c:

pktgen before:
  713773-721062(718374+/-2.1e+03)pps 331-334(332.95+/-0.92)Mb/sec (331190672-334572768(3.33325e+08+/-9.6e+05)bps) errors: 0
pktgen after:
  710542-719195(714898+/-2.4e+03)pps 329-333(331.15+/-1.1)Mb/sec (329691488-333706480(3.31713e+08+/-1.1e+06)bps) errors: 0

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 12:52:35 -04:00
Rusty Russell eeebf9b1fc virtio_ring: assume sgs are always well-formed.
We used to have several callers which just used arrays.  They're
gone, so we can use sg_next() everywhere, simplifying the code.

On my laptop, this slowed down vring_bench by 15%:

vring_bench before:
	936153354-967745359(9.44739e+08+/-6.1e+06)ns
vring_bench after:
	1061485790-1104800648(1.08254e+09+/-6.6e+06)ns

However, a more realistic test using pktgen on a AMD FX(tm)-8320 saw
a few percent improvement:

pktgen before:
  767390-792966(785159+/-6.5e+03)pps 356-367(363.75+/-2.9)Mb/sec (356068960-367936224(3.64314e+08+/-3e+06)bps) errors: 0

pktgen after:
   787781-796334(793165+/-2.4e+03)pps 365-369(367.5+/-1.2)Mb/sec (365530384-369498976(3.68028e+08+/-1.1e+06)bps) errors: 0

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 12:50:46 -04:00
Rusty Russell e2dcdfe95c virtio: virtio_break_device() to mark all virtqueues broken.
Good for post-apocalyptic scenarios, like S/390 hotplug.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-28 11:34:13 +09:30
Rusty Russell 70670444c2 virtio: fail adding buffer on broken queues.
Heinz points out that adding buffers to a broken virtqueue (which
should "never happen") still works.  Failing allows drivers to detect
and complain about broken devices.

Now drivers are robust, we can add this extra check.

Reported-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 11:27:57 +10:30
Joel Stanley 6abb2dd928 tools/virtio: fix missing kmemleak_ignore symbol
In commit bb478d8b16 virtio_ring: plug kmemleak false positive,
kmemleak_ignore was introduced. This broke compilation of virtio_test:

  cc -g -O2 -Wall -I. -I ../../usr/include/ -Wno-pointer-sign
    -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD
    -U_FORTIFY_SOURCE   -c -o virtio_ring.o ../../drivers/virtio/virtio_ring.c
  ../../drivers/virtio/virtio_ring.c: In function ‘vring_add_indirect’:
  ../../drivers/virtio/virtio_ring.c:177:2: warning: implicit declaration
  of function ‘kmemleak_ignore’ [-Wimplicit-function-declaration]
    kmemleak_ignore(desc);
    ^
  cc   virtio_test.o virtio_ring.o   -o virtio_test
  virtio_ring.o: In function `vring_add_indirect':
  tools/virtio/../../drivers/virtio/virtio_ring.c:177:
  undefined reference to `kmemleak_ignore'

Add a dummy header for tools/virtio, and add #incldue <linux/kmemleak.h>
to drivers/virtio/virtio_ring.c so it is picked up by the userspace
tools.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 11:23:25 +10:30
Heinz Graalfs 2342d6a651 virtio_ring: adapt to notify() returning bool
Correct if statement to check for bool returned by notify()
(introduced in 5b1bf7cb67).

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-11-05 21:21:08 +10:30
Heinz Graalfs b3b32c9413 virtio_ring: add new function virtqueue_is_broken()
Add new function virtqueue_is_broken(). Callers of virtqueue_get_buf()
should check for a broken queue.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29 11:28:17 +10:30
Heinz Graalfs 5b1bf7cb67 virtio_ring: let virtqueue_{kick()/notify()} return a bool
virtqueue_{kick()/notify()} should exploit the new host notification API.
If the notify call returned with a negative value the host kick failed
(e.g. a kick triggered after a device was hot-unplugged). In this case
the virtqueue is set to 'broken' and false is returned, otherwise true.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29 11:28:12 +10:30
Heinz Graalfs 46f9c2b925 virtio_ring: change host notification API
Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host notification seems to be one
prerequisite in order to be able to handle such errors in the context
where the kick is triggered.

This patch changes the notify API. The notify function must return a
bool return value. It returns false if the host notification failed.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29 11:28:11 +10:30
Rusty Russell bb478d8b16 virtio_ring: plug kmemleak false positive.
unreferenced object 0xffff88003d467e20 (size 32):
  comm "softirq", pid 0, jiffies 4295197765 (age 6.364s)
  hex dump (first 32 bytes):
    28 19 bf 3d 00 00 00 00 0c 00 00 00 01 00 01 00  (..=............
    02 dc 51 3c 00 00 00 00 56 00 00 00 00 00 00 00  ..Q<....V.......
  backtrace:
    [<ffffffff8152db19>] kmemleak_alloc+0x59/0xc0
    [<ffffffff81102e93>] __kmalloc+0xf3/0x180
    [<ffffffff812db5d6>] vring_add_indirect+0x36/0x280
    [<ffffffff812dc59f>] virtqueue_add_outbuf+0xbf/0x4e0
    [<ffffffff813a8b30>] start_xmit+0x1a0/0x3b0
    [<ffffffff81445861>] dev_hard_start_xmit+0x2d1/0x4d0
    [<ffffffff81460052>] sch_direct_xmit+0xf2/0x1c0
    [<ffffffff81445c28>] dev_queue_xmit+0x1c8/0x460
    [<ffffffff814e3187>] ip6_finish_output2+0x1d7/0x470
    [<ffffffff814e34b0>] ip6_finish_output+0x90/0xb0
    [<ffffffff814e3507>] ip6_output+0x37/0xb0
    [<ffffffff815021eb>] igmp6_send+0x2db/0x470
    [<ffffffff81502645>] igmp6_timer_handler+0x95/0xa0
    [<ffffffff8104b57c>] call_timer_fn+0x2c/0x90
    [<ffffffff8104b7ba>] run_timer_softirq+0x1da/0x1f0
    [<ffffffff81045721>] __do_softirq+0xd1/0x1b0

Address gets embedded in a descriptor via virt_to_phys().  See detach_buf,
which frees it:

	if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT)
		kfree(phys_to_virt(vq->vring.desc[i].addr));

Reported-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Fix-suggested-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Typing-done-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-17 10:55:35 +10:30
Linus Torvalds 496322bc91 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:
 "This is a re-do of the net-next pull request for the current merge
  window.  The only difference from the one I made the other day is that
  this has Eliezer's interface renames and the timeout handling changes
  made based upon your feedback, as well as a few bug fixes that have
  trickeled in.

  Highlights:

   1) Low latency device polling, eliminating the cost of interrupt
      handling and context switches.  Allows direct polling of a network
      device from socket operations, such as recvmsg() and poll().

      Currently ixgbe, mlx4, and bnx2x support this feature.

      Full high level description, performance numbers, and design in
      commit 0a4db187a9 ("Merge branch 'll_poll'")

      From Eliezer Tamir.

   2) With the routing cache removed, ip_check_mc_rcu() gets exercised
      more than ever before in the case where we have lots of multicast
      addresses.  Use a hash table instead of a simple linked list, from
      Eric Dumazet.

   3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from
      Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski,
      Marek Puzyniak, Michal Kazior, and Sujith Manoharan.

   4) Support reporting the TUN device persist flag to userspace, from
      Pavel Emelyanov.

   5) Allow controlling network device VF link state using netlink, from
      Rony Efraim.

   6) Support GRE tunneling in openvswitch, from Pravin B Shelar.

   7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from
      Daniel Borkmann and Eric Dumazet.

   8) Allow controlling of TCP quickack behavior on a per-route basis,
      from Cong Wang.

   9) Several bug fixes and improvements to vxlan from Stephen
      Hemminger, Pravin B Shelar, and Mike Rapoport.  In particular,
      support receiving on multiple UDP ports.

  10) Major cleanups, particular in the area of debugging and cookie
      lifetime handline, to the SCTP protocol code.  From Daniel
      Borkmann.

  11) Allow packets to cross network namespaces when traversing tunnel
      devices.  From Nicolas Dichtel.

  12) Allow monitoring netlink traffic via AF_PACKET sockets, in a
      manner akin to how we monitor real network traffic via ptype_all.
      From Daniel Borkmann.

  13) Several bug fixes and improvements for the new alx device driver,
      from Johannes Berg.

  14) Fix scalability issues in the netem packet scheduler's time queue,
      by using an rbtree.  From Eric Dumazet.

  15) Several bug fixes in TCP loss recovery handling, from Yuchung
      Cheng.

  16) Add support for GSO segmentation of MPLS packets, from Simon
      Horman.

  17) Make network notifiers have a real data type for the opaque
      pointer that's passed into them.  Use this to properly handle
      network device flag changes in arp_netdev_event().  From Jiri
      Pirko and Timo Teräs.

  18) Convert several drivers over to module_pci_driver(), from Peter
      Huewe.

  19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a
      O(1) calculation instead.  From Eric Dumazet.

  20) Support setting of explicit tunnel peer addresses in ipv6, just
      like ipv4.  From Nicolas Dichtel.

  21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet.

  22) Prevent a single high rate flow from overruning an individual cpu
      during RX packet processing via selective flow shedding.  From
      Willem de Bruijn.

  23) Don't use spinlocks in TCP md5 signing fast paths, from Eric
      Dumazet.

  24) Don't just drop GSO packets which are above the TBF scheduler's
      burst limit, chop them up so they are in-bounds instead.  Also
      from Eric Dumazet.

  25) VLAN offloads are missed when configured on top of a bridge, fix
      from Vlad Yasevich.

  26) Support IPV6 in ping sockets.  From Lorenzo Colitti.

  27) Receive flow steering targets should be updated at poll() time
      too, from David Majnemer.

  28) Fix several corner case regressions in PMTU/redirect handling due
      to the routing cache removal, from Timo Teräs.

  29) We have to be mindful of ipv4 mapped ipv6 sockets in
      upd_v6_push_pending_frames().  From Hannes Frederic Sowa.

  30) Fix L2TP sequence number handling bugs, from James Chapman."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits)
  drivers/net: caif: fix wrong rtnl_is_locked() usage
  drivers/net: enic: release rtnl_lock on error-path
  vhost-net: fix use-after-free in vhost_net_flush
  net: mv643xx_eth: do not use port number as platform device id
  net: sctp: confirm route during forward progress
  virtio_net: fix race in RX VQ processing
  virtio: support unlocked queue poll
  net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit
  Documentation: Fix references to defunct linux-net@vger.kernel.org
  net/fs: change busy poll time accounting
  net: rename low latency sockets functions to busy poll
  bridge: fix some kernel warning in multicast timer
  sfc: Fix memory leak when discarding scattered packets
  sit: fix tunnel update via netlink
  dt:net:stmmac: Add dt specific phy reset callback support.
  dt:net:stmmac: Add support to dwmac version 3.610 and 3.710
  dt:net:stmmac: Allocate platform data only if its NULL.
  net:stmmac: fix memleak in the open method
  ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available
  net: ipv6: fix wrong ping_v6_sendmsg return value
  ...
2013-07-09 18:24:39 -07:00
Michael S. Tsirkin cc229884d3 virtio: support unlocked queue poll
This adds a way to check ring empty state after enable_cb outside any
locks. Will be used by virtio_net.

Note: there's room for more optimization: caller is likely to have a
memory barrier already, which means we might be able to get rid of a
barrier here.  Deferring this optimization until we do some
benchmarking.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-09 12:45:37 -07:00
Rusty Russell b3087e48ce virtio: remove virtqueue_add_buf().
All users changed to virtqueue_add_sg() or virtqueue_add_outbuf/inbuf.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-05-20 12:16:01 +09:30
Rusty Russell 282edb3649 virtio_ring: virtqueue_add_outbuf / virtqueue_add_inbuf.
These are specialized versions of virtqueue_add_buf(), which cover
over 80% of cases and are far clearer.

In particular, the scatterlists passed to these functions don't have
to be clean (ie. we ignore end markers).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-03-20 15:44:52 +10:30
Rusty Russell 13816c768d virtio_ring: virtqueue_add_sgs, to add multiple sgs.
virtio_scsi can really use this, to avoid the current hack of copying
the whole sg array.  Some other things get slightly neater, too.

This causes a slowdown in virtqueue_add_buf(), which is implemented as
a wrapper.  This is addressed in the next patches.

for i in `seq 50`; do /usr/bin/time -f 'Wall time:%e' ./vringh_test --indirect --eventidx --parallel --fast-vringh; done 2>&1 | stats --trim-outliers:

Before:
	Using CPUS 0 and 3
	Guest: notified 0, pinged 39009-39063(39062)
	Host: notified 39009-39063(39062), pinged 0
	Wall time:1.700000-1.950000(1.723542)

After:
	Using CPUS 0 and 3
	Guest: notified 0, pinged 39062-39063(39063)
	Host: notified 39062-39063(39063), pinged 0
	Wall time:1.760000-2.220000(1.789167)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
2013-03-20 15:43:29 +10:30
Rusty Russell a9a0fef779 virtio_ring: expose virtio barriers for use in vringh.
The host side of ring needs this logic too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-03-20 14:00:41 +10:30
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
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
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
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
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