Граф коммитов

131 Коммитов

Автор SHA1 Сообщение Дата
Jason Wang 8d65843c44 Revert "vhost: cache used event for better performance"
This reverts commit 809ecb9bca. Since it
was reported to break vhost_net. We want to cache used event and use
it to check for notification. The assumption was that guest won't move
the event idx back, but this could happen in fact when 16 bit index
wraps around after 64K entries.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-29 14:15:56 -07:00
Ingo Molnar ac6424b981 sched/wait: Rename wait_queue_t => wait_queue_entry_t
Rename:

	wait_queue_t		=>	wait_queue_entry_t

'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.

Start sorting this out by renaming it to 'wait_queue_entry_t'.

This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20 12:18:27 +02:00
Michal Hocko 6c5ab6511f mm: support __GFP_REPEAT in kvmalloc_node for >32kB
vhost code uses __GFP_REPEAT when allocating vhost_virtqueue resp.
vhost_vsock because it would really like to prefer kmalloc to the
vmalloc fallback - see 23cc5a991c ("vhost-net: extend device
allocation to vmalloc") for more context.  Michael Tsirkin has also
noted:

 "__GFP_REPEAT overhead is during allocation time. Using vmalloc means
  all accesses are slowed down. Allocation is not on data path, accesses
  are."

The similar applies to other vhost_kvzalloc users.

Let's teach kvmalloc_node to handle __GFP_REPEAT properly.  There are
two things to be careful about.  First we should prevent from the OOM
killer and so have to involve __GFP_NORETRY by default and secondly
override __GFP_REPEAT for !costly order requests as the __GFP_REPEAT is
ignored for !costly orders.

Supporting __GFP_REPEAT like semantic for !costly request is possible it
would require changes in the page allocator.  This is out of scope of
this patch.

This patch shouldn't introduce any functional change.

Link: http://lkml.kernel.org/r/20170306103032.2540-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:12 -07:00
Linus Torvalds 1827adb11a Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull sched.h split-up from Ingo Molnar:
 "The point of these changes is to significantly reduce the
  <linux/sched.h> header footprint, to speed up the kernel build and to
  have a cleaner header structure.

  After these changes the new <linux/sched.h>'s typical preprocessed
  size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
  lines), which is around 40% faster to build on typical configs.

  Not much changed from the last version (-v2) posted three weeks ago: I
  eliminated quirks, backmerged fixes plus I rebased it to an upstream
  SHA1 from yesterday that includes most changes queued up in -next plus
  all sched.h changes that were pending from Andrew.

  I've re-tested the series both on x86 and on cross-arch defconfigs,
  and did a bisectability test at a number of random points.

  I tried to test as many build configurations as possible, but some
  build breakage is probably still left - but it should be mostly
  limited to architectures that have no cross-compiler binaries
  available on kernel.org, and non-default configurations"

* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
  sched/headers: Clean up <linux/sched.h>
  sched/headers: Remove #ifdefs from <linux/sched.h>
  sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
  sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
  sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
  sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
  sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
  sched/core: Remove unused prefetch_stack()
  sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
  sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
  sched/headers: Remove <linux/signal.h> from <linux/sched.h>
  sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
  sched/headers: Remove the runqueue_is_locked() prototype
  sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
  sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
  sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
  ...
2017-03-03 10:16:38 -08:00
Linus Torvalds 54d7989f47 virtio, vhost: optimizations, fixes
Looks like a quiet cycle for vhost/virtio, just a couple of minor
 tweaks. Most notable is automatic interrupt affinity for blk and scsi.
 Hopefully other devices are not far behind.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull vhost updates from Michael Tsirkin:
 "virtio, vhost: optimizations, fixes

  Looks like a quiet cycle for vhost/virtio, just a couple of minor
  tweaks. Most notable is automatic interrupt affinity for blk and scsi.
  Hopefully other devices are not far behind"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio-console: avoid DMA from stack
  vhost: introduce O(1) vq metadata cache
  virtio_scsi: use virtio IRQ affinity
  virtio_blk: use virtio IRQ affinity
  blk-mq: provide a default queue mapping for virtio device
  virtio: provide a method to get the IRQ affinity mask for a virtqueue
  virtio: allow drivers to request IRQ affinity when creating VQs
  virtio_pci: simplify MSI-X setup
  virtio_pci: don't duplicate the msix_enable flag in struct pci_dev
  virtio_pci: use shared interrupts for virtqueues
  virtio_pci: remove struct virtio_pci_vq_info
  vhost: try avoiding avail index access when getting descriptor
  virtio_mmio: expose header to userspace
2017-03-02 13:53:13 -08:00
Ingo Molnar 174cd4b1e5 sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>
Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:32 +01:00
Ingo Molnar 6e84f31522 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h>
We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/mm.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

The APIs that are going to be moved first are:

   mm_alloc()
   __mmdrop()
   mmdrop()
   mmdrop_async_fn()
   mmdrop_async()
   mmget_not_zero()
   mmput()
   mmput_async()
   get_task_mm()
   mm_access()
   mm_release()

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:28 +01:00
Jason Wang f889491380 vhost: introduce O(1) vq metadata cache
When device IOTLB is enabled, all address translations were stored in
interval tree. O(lgN) searching time could be slow for virtqueue
metadata (avail, used and descriptors) since they were accessed much
often than other addresses. So this patch introduces an O(1) array
which points to the interval tree nodes that store the translations of
vq metadata. Those array were update during vq IOTLB prefetching and
were reset during each invalidation and tlb update. Each time we want
to access vq metadata, this small array were queried before interval
tree. This would be sufficient for static mappings but not dynamic
mappings, we could do optimizations on top.

Test were done with l2fwd in guest (2M hugepage):

   noiommu  | before        | after
tx 1.32Mpps | 1.06Mpps(82%) | 1.30Mpps(98%)
rx 2.33Mpps | 1.46Mpps(63%) | 2.29Mpps(98%)

We can almost reach the same performance as noiommu mode.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-03-02 01:35:06 +02:00
Jason Wang e3b56cdd43 vhost: try avoiding avail index access when getting descriptor
If last avail idx is not equal to cached avail idx, we're sure there's
still available buffers in the virtqueue so there's no need to re-read
avail idx. So let's skip this to avoid unnecessary userspace memory
access and memory barrier. Pktgen test show about 3% improvement on rx
pps.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-02-27 20:37:27 +02:00
David S. Miller 3efa70d78f Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
The conflict was an interaction between a bug fix in the
netvsc driver in 'net' and an optimization of the RX path
in 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-07 16:29:30 -05:00
Halil Pasic cda8bba0f9 vhost: fix initialization for vq->is_le
Currently, under certain circumstances vhost_init_is_le does just a part
of the initialization job, and depends on vhost_reset_is_le being called
too. For this reason vhost_vq_init_access used to call vhost_reset_is_le
when vq->private_data is NULL. This is not only counter intuitive, but
also real a problem because it breaks vhost_net. The bug was introduced to
vhost_net with commit 2751c9882b ("vhost: cross-endian support for
legacy devices"). The symptom is corruption of the vq's used.idx field
(virtio) after VHOST_NET_SET_BACKEND was issued as a part of the vhost
shutdown on a vq with pending descriptors.

Let us make sure the outcome of vhost_init_is_le never depend on the state
it is actually supposed to initialize, and fix virtio_net by removing the
reset from vhost_vq_init_access.

With the above, there is no reason for vhost_reset_is_le to do just half
of the job. Let us make vhost_reset_is_le reinitialize is_le.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reported-by: Michael A. Tebolt <miket@us.ibm.com>
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fixes: commit 2751c9882b ("vhost: cross-endian support for legacy devices")
Cc: <stable@vger.kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Michael A. Tebolt <miket@us.ibm.com>
2017-02-03 23:38:57 +02:00
Jason Wang 275bf960ac vhost: better detection of available buffers
This patch tries to do several tweaks on vhost_vq_avail_empty() for a
better performance:

- check cached avail index first which could avoid userspace memory access.
- using unlikely() for the failure of userspace access
- check vq->last_avail_idx instead of cached avail index as the last
  step.

This patch is need for batching supports which needs to peek whether
or not there's still available buffers in the ring.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-18 16:35:29 -05:00
Linus Torvalds 9a19a6db37 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:

 - more ->d_init() stuff (work.dcache)

 - pathname resolution cleanups (work.namei)

 - a few missing iov_iter primitives - copy_from_iter_full() and
   friends. Either copy the full requested amount, advance the iterator
   and return true, or fail, return false and do _not_ advance the
   iterator. Quite a few open-coded callers converted (and became more
   readable and harder to fuck up that way) (work.iov_iter)

 - several assorted patches, the big one being logfs removal

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  logfs: remove from tree
  vfs: fix put_compat_statfs64() does not handle errors
  namei: fold should_follow_link() with the step into not-followed link
  namei: pass both WALK_GET and WALK_MORE to should_follow_link()
  namei: invert WALK_PUT logics
  namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
  namei: saner calling conventions for mountpoint_last()
  namei.c: get rid of user_path_parent()
  switch getfrag callbacks to ..._full() primitives
  make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success
  [iov_iter] new primitives - copy_from_iter_full() and friends
  don't open-code file_inode()
  ceph: switch to use of ->d_init()
  ceph: unify dentry_operations instances
  lustre: switch to use of ->d_init()
2016-12-16 10:24:44 -08:00
Jason Wang 809ecb9bca vhost: cache used event for better performance
When event index was enabled, we need to fetch used event from
userspace memory each time. This userspace fetch (with memory
barrier) could be saved sometime when 1) caching used event and 2)
if used event is ahead of new and old to new updating does not cross
it, we're sure there's no need to notify guest.

This will be useful for heavy tx load e.g guest pktgen test with Linux
driver shows ~3.5% improvement.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-16 00:12:50 +02:00
Michael S. Tsirkin 72952cc061 vhost: add missing __user annotations
Several vhost functions were missing __user annotations
on pointers, causing sparse warnings. Fix this up.

sparse also warns about vhost_process_iotlb_msg which
is local and should be static. Fix that up as well.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-15 06:59:18 +02:00
Michael S. Tsirkin 2f952c0105 vhost: make interval tree static inline
vhost_umem_interval_tree is only used locally within vhost.c, mark it
static. As some functions generated go unused, this triggers warnings
unless we also mark it inline.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-15 06:59:17 +02:00
Peng Tao 635abf0191 vhost: remove unnecessary smp_mb from vhost_work_queue
test_and_set_bit() already implies a memory barrier.

Signed-off-by: Peng Tao <bergwolf@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-08 11:26:46 -05:00
Al Viro cbbd26b8b1 [iov_iter] new primitives - copy_from_iter_full() and friends
copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.

Convert some obvious users.  *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case.  Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 14:33:36 -05:00
Michael S. Tsirkin ec33d031a1 vhost: detect 32 bit integer wrap around
Detect and fail early if long wrap around is triggered.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-02 16:54:28 +03:00
Jason Wang 6b1e6cc785 vhost: new device IOTLB API
This patch tries to implement an device IOTLB for vhost. This could be
used with userspace(qemu) implementation of DMA remapping
to emulate an IOMMU for the guest.

The idea is simple, cache the translation in a software device IOTLB
(which is implemented as an interval tree) in vhost and use vhost_net
file descriptor for reporting IOTLB miss and IOTLB
update/invalidation. When vhost meets an IOTLB miss, the fault
address, size and access can be read from the file. After userspace
finishes the translation, it writes the translated address to the
vhost_net file to update the device IOTLB.

When device IOTLB is enabled by setting VIRTIO_F_IOMMU_PLATFORM all vq
addresses set by ioctl are treated as iova instead of virtual address and
the accessing can only be done through IOTLB instead of direct userspace
memory access. Before each round or vq processing, all vq metadata is
prefetched in device IOTLB to make sure no translation fault happens
during vq processing.

In most cases, virtqueues are contiguous even in virtual address space.
The IOTLB translation for virtqueue itself may make it a little
slower. We might add fast path cache on top of this patch.

Signed-off-by: Jason Wang <jasowang@redhat.com>
[mst: use virtio feature bit: VHOST_F_DEVICE_IOTLB -> VIRTIO_F_IOMMU_PLATFORM ]
[mst: fix build warnings ]
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
[ weiyj.lk: missing unlock on error ]
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
2016-08-02 16:53:54 +03:00
Jason Wang a9709d6874 vhost: convert pre sorted vhost memory array to interval tree
Current pre-sorted memory region array has some limitations for future
device IOTLB conversion:

1) need extra work for adding and removing a single region, and it's
   expected to be slow because of sorting or memory re-allocation.
2) need extra work of removing a large range which may intersect
   several regions with different size.
3) need trick for a replacement policy like LRU

To overcome the above shortcomings, this patch convert it to interval
tree which can easily address the above issue with almost no extra
work.

The patch could be used for:

- Extend the current API and only let the userspace to send diffs of
  memory table.
- Simplify Device IOTLB implementation.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-02 02:57:31 +03:00
Jason Wang bfe2bc5128 vhost: introduce vhost memory accessors
This patch introduces vhost memory accessors which were just wrappers
for userspace address access helpers. This is a requirement for vhost
device iotlb implementation which will add iotlb translations in those
accessors.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-02 02:57:30 +03:00
Jason Wang 04b96e5528 vhost: lockless enqueuing
We use spinlock to synchronize the work list now which may cause
unnecessary contentions. So this patch switch to use llist to remove
this contention. Pktgen tests shows about 5% improvement:

Before:
~1300000 pps
After:
~1370000 pps

Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-01 21:44:51 +03:00
Jason Wang 7235acdb11 vhost: simplify work flushing
We used to implement the work flushing through tracking queued seq,
done seq, and the number of flushing. This patch simplify this by just
implement work flushing through another kind of vhost work with
completion. This will be used by lockless enqueuing patch.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-08-01 21:44:50 +03:00
Jason Wang 0308813724 vhost_net: basic polling support
This patch tries to poll for new added tx buffer or socket receive
queue for a while at the end of tx/rx processing. The maximum time
spent on polling were specified through a new kind of vring ioctl.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-11 02:18:53 +02:00
Jason Wang d4a60603fa vhost: introduce vhost_vq_avail_empty()
This patch introduces a helper which will return true if we're sure
that the available ring is empty for a specific vq. When we're not
sure, e.g vq access failure, return false instead. This could be used
for busy polling code to exit the busy loop.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-11 02:18:50 +02:00
Jason Wang 526d3e7ff5 vhost: introduce vhost_has_work()
This path introduces a helper which can give a hint for whether or not
there's a work queued in the work list. This could be used for busy
polling code to exit the busy loop.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-11 02:18:45 +02:00
Greg Kurz 80f7d0301e vhost: rename vhost_init_used()
Looking at how callers use this, maybe we should just rename init_used
to vhost_vq_init_access. The _used suffix was a hint that we
access the vq used ring. But maybe what callers care about is
that it must be called after access_ok.

Also, this function manipulates the vq->is_le field which isn't related
to the vq used ring.

This patch simply renames vhost_init_used() to vhost_vq_init_access() as
suggested by Michael.

No behaviour change.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:02:04 +02:00
Greg Kurz c507203756 vhost: rename cross-endian helpers
The default use case for vhost is when the host and the vring have the
same endianness (default native endianness). But there are cases where
they differ and vhost should byteswap when accessing the vring.

The first case is when the host is big endian and the vring belongs to
a virtio 1.0 device, which is always little endian.

This is covered by the vq->is_le field. This field is initialized when
userspace calls the VHOST_SET_FEATURES ioctl. It is reset when the device
stops.

We already have a vhost_init_is_le() helper, but the reset operation is
opencoded as follows:

	vq->is_le = virtio_legacy_is_little_endian();

It isn't clear that we are resetting vq->is_le here.

This patch moves the code to a helper with a more explicit name.

The other case where we may have to byteswap is when the architecture can
switch endianness at runtime (bi-endian). If endianness differs in the host
and in the guest, then legacy devices need to be used in cross-endian mode.

This mode is available with CONFIG_VHOST_CROSS_ENDIAN_LEGACY=y, which
introduces a vq->user_be field. Userspace may enable cross-endian mode
by calling the SET_VRING_ENDIAN ioctl before the device is started. The
cross-endian mode is disabled when the device is stopped.

The current names of the helpers that manipulate vq->user_be are unclear.

This patch renames those helpers to clearly show that this is cross-endian
stuff and with explicit enable/disable semantics.

No behaviour change.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:02:00 +02:00
Greg Kurz e1f33be918 vhost: fix error path in vhost_init_used()
We don't want side effects. If something fails, we rollback vq->is_le to
its previous value.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02 17:01:49 +02:00
Michael S. Tsirkin 5fba13b5cf vhost: replace % with & on data path
We know vring num is a power of 2, so use &
to mask the high bits.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-07 17:28:10 +02:00
Michael S. Tsirkin d542483876 vhost: relax log address alignment
commit 5d9a07b0de ("vhost: relax used
address alignment") fixed the alignment for the used virtual address,
but not for the physical address used for logging.

That's a mistake: alignment should clearly be the same for virtual and
physical addresses,

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-07 17:27:54 +02:00
Igor Mammedov 1e0994730f vhost: fix error handling for memory region alloc
callers of vhost_kvzalloc() expect the same behaviour on
allocation error as from kmalloc/vmalloc i.e. NULL return
value. So just return vzmalloc() returned value instead of
returning ERR_PTR(-ENOMEM)

Fixes: 4de7255f7d ("vhost: extend memory regions allocation to vmalloc")

Spotted-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-07-27 18:05:05 +03:00
Marc-André Lureau 7932c0bd77 vhost: actually track log eventfd file
While reviewing vhost log code, I found out that log_file is never
set. Note: I haven't tested the change (QEMU doesn't use LOG_FD yet).

Cc: stable@vger.kernel.org
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-07-27 18:04:58 +03:00
Igor Mammedov c9ce42f72f vhost: add max_mem_regions module parameter
it became possible to use a bigger amount of memory
slots, which is used by memory hotplug for
registering hotplugged memory.
However QEMU crashes if it's used with more than ~60
pc-dimm devices and vhost-net enabled since host kernel
in module vhost-net refuses to accept more than 64
memory regions.

Allow to tweak limit via max_mem_regions module paramemter
with default value set to 64 slots.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-07-13 23:17:19 +03:00
Igor Mammedov 4de7255f7d vhost: extend memory regions allocation to vmalloc
with large number of memory regions we could end up with
high order allocations and kmalloc could fail if
host is under memory pressure.
Considering that memory regions array is used on hot path
try harder to allocate using kmalloc and if it fails resort
to vmalloc.
It's still better than just failing vhost_set_memory() and
causing guest crash due to it when a new memory hotplugged
to guest.

I'll still look at QEMU side solution to reduce amount of
memory regions it feeds to vhost to make things even better,
but it doesn't hurt for kernel to behave smarter and don't
crash older QEMU's which could use large amount of memory
regions.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-07-13 23:17:18 +03:00
Igor Mammedov bcfeacab45 vhost: use binary search instead of linear in find_region()
For default region layouts performance stays the same
as linear search i.e. it takes around 210ns average for
translate_desc() that inlines find_region().

But it scales better with larger amount of regions,
235ns BS vs 300ns LS with 55 memory regions
and it will be about the same values when allowed number
of slots is increased to 509 like it has been done in kvm.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-07-01 10:12:12 +02:00
Greg Kurz 2751c9882b vhost: cross-endian support for legacy devices
This patch brings cross-endian support to vhost when used to implement
legacy virtio devices. Since it is a relatively rare situation, the
feature availability is controlled by a kernel config option (not set
by default).

The vq->is_le boolean field is added to cache the endianness to be
used for ring accesses. It defaults to native endian, as expected
by legacy virtio devices. When the ring gets active, we force little
endian if the device is modern. When the ring is deactivated, we
revert to the native endian default.

If cross-endian was compiled in, a vq->user_be boolean field is added
so that userspace may request a specific endianness. This field is
used to override the default when activating the ring of a legacy
device. It has no effect on modern devices.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2015-06-01 15:48:55 +02:00
Al Viro aad9a1cec7 vhost: switch vhost get_indirect() to iov_iter, kill memcpy_fromiovec()
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-04 01:34:15 -05:00
Michael S. Tsirkin 5d9a07b0de vhost: relax used address alignment
virtio 1.0 only requires used address to be 4 byte aligned,
vhost required 8 bytes (size of vring_used_elem).
Fix up vhost to match that.

Additionally, while vhost correctly requires 8 byte
alignment for log, it's unconnected to used ring:
it's a consequence that log has u64 entries.
Tweak code to make that clearer.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-12-29 10:55:06 +02:00
Michael S. Tsirkin 3b1bbe8935 vhost: virtio 1.0 endian-ness support
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-12-09 12:05:29 +02:00
Michael S. Tsirkin 64f7f0510c vhost: switch to __get/__put_user exclusively
Most places in vhost can use __get/__put_user rather than
get/put_user since addresses are pre-validated.
This should be good for performance, but this also
will help make code sparse-clean: get/put_user macros
don't play well with __virtioXX bitwise tags.
Switch to get/put_user to __ variants everywhere in vhost.
There's one exception - for consistency switch that
as well, and add an explicit access_ok check.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-12-09 12:05:29 +02:00
Michael S. Tsirkin 47283bef7e vhost: move memory pointer to VQs
commit 2ae76693b8bcabf370b981cd00c36cd41d33fabc
    vhost: replace rcu with mutex
replaced rcu sync for memory accesses with VQ mutex locl/unlock.
This is correct since all accesses are under VQ mutex, but incomplete:
we still do useless rcu lock/unlock operations, someone might copy this
code into some other context where this won't be right.
This use of RCU is also non standard and hard to understand.
Let's copy the pointer to each VQ structure, this way
the access rules become straight-forward, and there's
no need for RCU anymore.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-09 16:21:07 +03:00
Michael S. Tsirkin ea16c51433 vhost: move acked_features to VQs
Refactor code to make sure features are only accessed
under VQ mutex. This makes everything simpler, no need
for RCU here anymore.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-09 16:21:06 +03:00
Michael S. Tsirkin 98f9ca0a3f vhost: replace rcu with mutex
All memory accesses are done under some VQ mutex.
So lock/unlock all VQs is a faster equivalent of synchronize_rcu()
for memory access changes.
Some guests cause a lot of these changes, so it's helpful
to make them faster.

Reported-by: "Gonglei (Arei)" <arei.gonglei@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-09 16:21:06 +03:00
Zhi Yong Wu 59566b6e8c vhost: remove the dead branch
Since vhost_dev_init() forever return 0, some branches are never run,
therefore need to be removed.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 15:22:05 -05:00
Qin Chuanyu ac9fde2474 vhost: wake up worker outside spin_lock
the wake_up_process func is included by spin_lock/unlock in
vhost_work_queue,
but it could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2 using iperf,
the num as below.
                  original                 modified
thread_num  tp(Gbps)   vhost(%)  |  tp(Gbps)     vhost(%)
1           9.59        28.82    |   9.59        27.49
8           9.61        32.92    |   9.62        26.77
64          9.58        46.48    |   9.55        38.99
256         9.6         63.7     |   9.6         52.59

Signed-off-by: Chuanyu Qin <qinchuanyu@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-09-17 09:21:32 +03:00
Jason Wang c49e4e573b vhost: switch to use vhost_add_used_n()
Let vhost_add_used() to use vhost_add_used_n() to reduce the code
duplication. To avoid the overhead brought by __copy_to_user(). We will use
put_user() when one used need to be added.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-03 22:46:57 -04:00
Asias He 35596b2796 vhost: Include linux/uio.h instead of linux/socket.h
memcpy_fromiovec is moved from net/core/iovec.c to lib/iovec.c.
linux/uio.h provides the declaration for memcpy_fromiovec.

Include linux/uio.h instead of inux/socket.h for it.

Signed-off-by: Asias He <asias@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-20 15:05:04 -07:00
Asias He 6ac1afbf61 vhost: Make vhost a separate module
Currently, vhost-net and vhost-scsi are sharing the vhost core code.
However, vhost-scsi shares the code by including the vhost.c file
directly.

Making vhost a separate module makes it is easier to share code with
other vhost devices.

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-07-07 17:33:44 +03:00