01 May, 2016
1 commit
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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
Signed-off-by: Michael S. Tsirkin
02 Mar, 2016
4 commits
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Signed-off-by: Andy Lutomirski
Signed-off-by: Michael S. Tsirkin
Reviewed-by: David Vrabel
Reviewed-by: Wei Liu -
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
Signed-off-by: Michael S. Tsirkin -
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
Signed-off-by: Michael S. Tsirkin -
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
Signed-off-by: Michael S. Tsirkin
13 Jan, 2016
1 commit
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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
Acked-by: Peter Zijlstra (Intel)
07 Dec, 2015
2 commits
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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 elapsedThe 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
Signed-off-by: Michael S. Tsirkin -
b92b1b89a33c ("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
Signed-off-by: Michael S. Tsirkin
Acked-by: Will Deacon
Reviewed-by: Mel Gorman
11 Feb, 2015
1 commit
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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
Signed-off-by: Rusty Russell
21 Jan, 2015
1 commit
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Most of our code has
struct foo {
}Fix one instances where ring is inconsistent.
Signed-off-by: Michael S. Tsirkin
Signed-off-by: Rusty Russell
09 Dec, 2014
4 commits
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Activate VIRTIO_F_VERSION_1 automatically unless legacy_only
is set.Signed-off-by: Michael S. Tsirkin
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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
Signed-off-by: Cornelia HuckSigned-off-by: Michael S. Tsirkin
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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
Reviewed-by: Cornelia Huck -
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
Signed-off-by: Rusty Russell
Signed-off-by: Cornelia Huck
Signed-off-by: Michael S. Tsirkin
Reviewed-by: Cornelia Huck
14 Sep, 2014
2 commits
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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)nspktgen 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: 0pktgen 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: 0Now, 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: 0Signed-off-by: Rusty Russell
Signed-off-by: David S. Miller -
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)nsHowever, 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: 0pktgen 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: 0Signed-off-by: Rusty Russell
Signed-off-by: David S. Miller
28 Apr, 2014
1 commit
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Good for post-apocalyptic scenarios, like S/390 hotplug.
Signed-off-by: Rusty Russell
13 Mar, 2014
2 commits
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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
Signed-off-by: Rusty Russell -
In commit bb478d8b167 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
to drivers/virtio/virtio_ring.c so it is picked up by the userspace
tools.Signed-off-by: Joel Stanley
Signed-off-by: Rusty Russell
05 Nov, 2013
1 commit
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Correct if statement to check for bool returned by notify()
(introduced in 5b1bf7cb673a).Signed-off-by: Heinz Graalfs
Signed-off-by: Rusty Russell
29 Oct, 2013
3 commits
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Add new function virtqueue_is_broken(). Callers of virtqueue_get_buf()
should check for a broken queue.Signed-off-by: Heinz Graalfs
Signed-off-by: Rusty Russell -
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
Signed-off-by: Rusty Russell -
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
Signed-off-by: Rusty Russell
17 Oct, 2013
1 commit
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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] kmemleak_alloc+0x59/0xc0
[] __kmalloc+0xf3/0x180
[] vring_add_indirect+0x36/0x280
[] virtqueue_add_outbuf+0xbf/0x4e0
[] start_xmit+0x1a0/0x3b0
[] dev_hard_start_xmit+0x2d1/0x4d0
[] sch_direct_xmit+0xf2/0x1c0
[] dev_queue_xmit+0x1c8/0x460
[] ip6_finish_output2+0x1d7/0x470
[] ip6_finish_output+0x90/0xb0
[] ip6_output+0x37/0xb0
[] igmp6_send+0x2db/0x470
[] igmp6_timer_handler+0x95/0xa0
[] call_timer_fn+0x2c/0x90
[] run_timer_softirq+0x1da/0x1f0
[] __do_softirq+0xd1/0x1b0Address 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
Fix-suggested-by: Christoph Paasch
Typing-done-by: Rusty Russell
Signed-off-by: Rusty Russell
10 Jul, 2013
2 commits
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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 0a4db187a999 ("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
... -
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
Signed-off-by: David S. Miller
20 May, 2013
1 commit
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All users changed to virtqueue_add_sg() or virtqueue_add_outbuf/inbuf.
Signed-off-by: Rusty Russell
20 Mar, 2013
3 commits
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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
-
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
Reviewed-by: Wanlong Gao
Reviewed-by: Asias He -
The host side of ring needs this logic too.
Signed-off-by: Rusty Russell
18 Dec, 2012
2 commits
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Now noone relies on this behavior, we simplify virtqueue_add_buf() so it
return 0 or -errno.Signed-off-by: Rusty Russell
Acked-by: Michael S. Tsirkin -
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
Signed-off-by: Rusty Russell
22 Oct, 2012
1 commit
-
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
Signed-off-by: Will Deacon
Signed-off-by: Rusty Russell
28 Sep, 2012
1 commit
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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
Signed-off-by: Paolo Bonzini
Signed-off-by: Rusty Russell
28 Jan, 2012
2 commits
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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 ee7cd8981e15bcb365fc762afe3fc47b8242f630.
Signed-off-by: Jason Wang
Acked-by: Michael S. Tsirkin
Signed-off-by: Rusty Russell
Cc: stable@kernel.org -
Note: this fixes a bug introduced recently in
7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.Signed-off-by: Jason Wang
Acked-by: Michael S. Tsirkin
Signed-off-by: Rusty Russell
12 Jan, 2012
4 commits
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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
-
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
-
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
-
Based on patch by Christoph for virtio_blk speedup:
Split virtqueue_kick to be able to do the actual notification
outside the lock protecting the virtqueue. This patch was
originally done by Stefan Hajnoczi, but I can't find the
original one anymore and had to recreated it from memory.
Pointers to the original or corrections for the commit message
are welcome.Stefan's patch was here:
https://github.com/stefanha/linux/commit/a6d06644e3a58e57a774e77d7dc34c4a5a2e7496
http://www.spinics.net/lists/linux-virtualization/msg14616.htmlThird time's the charm!
Signed-off-by: Rusty Russell