<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/drivers/virtio, branch v6.1.83</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2023-11-02T08:35:23Z</updated>
<entry>
<title>virtio_pci: fix the common cfg map size</title>
<updated>2023-11-02T08:35:23Z</updated>
<author>
<name>Xuan Zhuo</name>
<email>xuanzhuo@linux.alibaba.com</email>
</author>
<published>2023-10-10T03:11:18Z</published>
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<content type='text'>
commit 061b39fdfe7fd98946e67637213bcbb10a318cca upstream.

The function vp_modern_map_capability() takes the size parameter,
which corresponds to the size of virtio_pci_common_cfg. As a result,
this indicates the size of memory area to map.

Now the size is the size of virtio_pci_common_cfg, but some feature(such
as the _F_RING_RESET) needs the virtio_pci_modern_common_cfg, so this
commit changes the size to the size of virtio_pci_modern_common_cfg.

Cc: stable@vger.kernel.org
Fixes: 0b50cece0b78 ("virtio_pci: introduce helper to get/set queue reset")
Signed-off-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Message-Id: &lt;20231010031120.81272-3-xuanzhuo@linux.alibaba.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Acked-by: Jason Wang &lt;jasowang@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>virtio-mmio: fix memory leak of vm_dev</title>
<updated>2023-11-02T08:35:23Z</updated>
<author>
<name>Maximilian Heyne</name>
<email>mheyne@amazon.de</email>
</author>
<published>2023-09-11T09:03:29Z</published>
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<content type='text'>
commit fab7f259227b8f70aa6d54e1de1a1f5f4729041c upstream.

With the recent removal of vm_dev from devres its memory is only freed
via the callback virtio_mmio_release_dev. However, this only takes
effect after device_add is called by register_virtio_device. Until then
it's an unmanaged resource and must be explicitly freed on error exit.

This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.

Cc: stable@vger.kernel.org
Fixes: 55c91fedd03d ("virtio-mmio: don't break lifecycle of vm_dev")
Signed-off-by: Maximilian Heyne &lt;mheyne@amazon.de&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Tested-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reviewed-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

Message-Id: &lt;20230911090328.40538-1-mheyne@amazon.de&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Reviewed-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
</content>
</entry>
<entry>
<title>virtio_balloon: Fix endless deflation and inflation on arm64</title>
<updated>2023-11-02T08:35:23Z</updated>
<author>
<name>Gavin Shan</name>
<email>gshan@redhat.com</email>
</author>
<published>2023-08-31T01:10:07Z</published>
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<id>urn:sha1:19b30a879065787cd6b56dc15b25a8880d8018de</id>
<content type='text'>
commit 07622bd415639e9709579f400afd19e7e9866e5e upstream.

The deflation request to the target, which isn't unaligned to the
guest page size causes endless deflation and inflation actions. For
example, we receive the flooding QMP events for the changes on memory
balloon's size after a deflation request to the unaligned target is
sent for the ARM64 guest, where we have 64KB base page size.

  /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64      \
  -accel kvm -machine virt,gic-version=host -cpu host          \
  -smp maxcpus=8,cpus=8,sockets=2,clusters=2,cores=2,threads=1 \
  -m 1024M,slots=16,maxmem=64G                                 \
  -object memory-backend-ram,id=mem0,size=512M                 \
  -object memory-backend-ram,id=mem1,size=512M                 \
  -numa node,nodeid=0,memdev=mem0,cpus=0-3                     \
  -numa node,nodeid=1,memdev=mem1,cpus=4-7                     \
    :                                                          \
  -device virtio-balloon-pci,id=balloon0,bus=pcie.10

  { "execute" : "balloon", "arguments": { "value" : 1073672192 } }
  {"return": {}}
  {"timestamp": {"seconds": 1693272173, "microseconds": 88667},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272174, "microseconds": 89704},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272175, "microseconds": 90819},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272176, "microseconds": 91961},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272177, "microseconds": 93040},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}}
  {"timestamp": {"seconds": 1693272178, "microseconds": 94117},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}}
  {"timestamp": {"seconds": 1693272179, "microseconds": 95337},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272180, "microseconds": 96615},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}}
  {"timestamp": {"seconds": 1693272181, "microseconds": 97626},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272182, "microseconds": 98693},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}}
  {"timestamp": {"seconds": 1693272183, "microseconds": 99698},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272184, "microseconds": 100727},  \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272185, "microseconds": 90430},   \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  {"timestamp": {"seconds": 1693272186, "microseconds": 102999},  \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}}
     :
  &lt;The similar QMP events repeat&gt;

Fix it by aligning the target up to the guest page size, 64KB in this
specific case. With this applied, no flooding QMP events are observed
and the memory balloon's size can be stablizied to 0x3ffe0000 soon
after the deflation request is sent.

  { "execute" : "balloon", "arguments": { "value" : 1073672192 } }
  {"return": {}}
  {"timestamp": {"seconds": 1693273328, "microseconds": 793075},  \
   "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}}
  { "execute" : "query-balloon" }
  {"return": {"actual": 1073610752}}

Cc: stable@vger.kernel.org
Signed-off-by: Gavin Shan &lt;gshan@redhat.com&gt;
Tested-by: Zhenyu Zhang &lt;zhenyzha@redhat.com&gt;
Message-Id: &lt;20230831011007.1032822-1-gshan@redhat.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>virtio_ring: fix avail_wrap_counter in virtqueue_add_packed</title>
<updated>2023-09-13T07:42:59Z</updated>
<author>
<name>Yuan Yao</name>
<email>yuanyaogoog@chromium.org</email>
</author>
<published>2023-08-08T05:10:59Z</published>
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<id>urn:sha1:ad8900dd8a568288cf6e332ffd4f11b2e74b17f4</id>
<content type='text'>
[ Upstream commit 1acfe2c1225899eab5ab724c91b7e1eb2881b9ab ]

In current packed virtqueue implementation, the avail_wrap_counter won't
flip, in the case when the driver supplies a descriptor chain with a
length equals to the queue size; total_sg == vq-&gt;packed.vring.num.

Let’s assume the following situation:
vq-&gt;packed.vring.num=4
vq-&gt;packed.next_avail_idx: 1
vq-&gt;packed.avail_wrap_counter: 0

Then the driver adds a descriptor chain containing 4 descriptors.

We expect the following result with avail_wrap_counter flipped:
vq-&gt;packed.next_avail_idx: 1
vq-&gt;packed.avail_wrap_counter: 1

But, the current implementation gives the following result:
vq-&gt;packed.next_avail_idx: 1
vq-&gt;packed.avail_wrap_counter: 0

To reproduce the bug, you can set a packed queue size as small as
possible, so that the driver is more likely to provide a descriptor
chain with a length equal to the packed queue size. For example, in
qemu run following commands:
sudo qemu-system-x86_64 \
-enable-kvm \
-nographic \
-kernel "path/to/kernel_image" \
-m 1G \
-drive file="path/to/rootfs",if=none,id=disk \
-device virtio-blk,drive=disk \
-drive file="path/to/disk_image",if=none,id=rwdisk \
-device virtio-blk,drive=rwdisk,packed=on,queue-size=4,\
indirect_desc=off \
-append "console=ttyS0 root=/dev/vda rw init=/bin/bash"

Inside the VM, create a directory and mount the rwdisk device on it. The
rwdisk will hang and mount operation will not complete.

This commit fixes the wrap counter error by flipping the
packed.avail_wrap_counter, when start of descriptor chain equals to the
end of descriptor chain (head == i).

Fixes: 1ce9e6055fa0 ("virtio_ring: introduce packed ring support")
Signed-off-by: Yuan Yao &lt;yuanyaogoog@chromium.org&gt;
Message-Id: &lt;20230808051110.3492693-1-yuanyaogoog@chromium.org&gt;
Acked-by: Jason Wang &lt;jasowang@redhat.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>virtio-mmio: don't break lifecycle of vm_dev</title>
<updated>2023-08-23T15:52:29Z</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2023-06-29T12:05:26Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=af5818c35173e096085c6ae2e3aac605d3d15e41'/>
<id>urn:sha1:af5818c35173e096085c6ae2e3aac605d3d15e41</id>
<content type='text'>
[ Upstream commit 55c91fedd03d7b9cf0c5199b2eb12b9b8e95281a ]

vm_dev has a separate lifecycle because it has a 'struct device'
embedded. Thus, having a release callback for it is correct.

Allocating the vm_dev struct with devres totally breaks this protection,
though. Instead of waiting for the vm_dev release callback, the memory
is freed when the platform_device is removed. Resulting in a
use-after-free when finally the callback is to be called.

To easily see the problem, compile the kernel with
CONFIG_DEBUG_KOBJECT_RELEASE and unbind with sysfs.

The fix is easy, don't use devres in this case.

Found during my research about object lifetime problems.

Fixes: 7eb781b1bbb7 ("virtio_mmio: add cleanup for virtio_mmio_probe")
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Message-Id: &lt;20230629120526.7184-1-wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>virtio_ring: don't update event idx on get_buf</title>
<updated>2023-05-11T14:03:31Z</updated>
<author>
<name>Albert Huang</name>
<email>huangjie.albert@bytedance.com</email>
</author>
<published>2023-03-29T10:23:00Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=ce818ee162cf4b528f717bbab089eeb6b54ff428'/>
<id>urn:sha1:ce818ee162cf4b528f717bbab089eeb6b54ff428</id>
<content type='text'>
[ Upstream commit 6c0b057cec5eade4c3afec3908821176931a9997 ]

In virtio_net, if we disable napi_tx, when we trigger a tx interrupt,
the vq-&gt;event_triggered will be set to true. It is then never reset
until we explicitly call virtqueue_enable_cb_delayed or
virtqueue_enable_cb_prepare.

If we disable the napi_tx, virtqueue_enable_cb* will only be called when
the tx ring is getting relatively empty.

Since event_triggered is true, VRING_AVAIL_F_NO_INTERRUPT or
VRING_PACKED_EVENT_FLAG_DISABLE will not be set. As a result we update
vring_used_event(&amp;vq-&gt;split.vring) or vq-&gt;packed.vring.driver-&gt;off_wrap
every time we call virtqueue_get_buf_ctx. This causes more interrupts.

To summarize:
1) event_triggered was set to true in vring_interrupt()
2) after this nothing will happen in virtqueue_disable_cb() so
   VRING_AVAIL_F_NO_INTERRUPT is not set in avail_flags_shadow
3) virtqueue_get_buf_ctx_split() will still think the cb is enabled
   and then it will publish a new event index

To fix:
update VRING_AVAIL_F_NO_INTERRUPT or VRING_PACKED_EVENT_FLAG_DISABLE in
the vq when we call virtqueue_disable_cb even when event_triggered is
true.

Tested with iperf:
iperf3 tcp stream:
vm1 -----------------&gt; vm2
vm2 just receives tcp data stream from vm1, and sends acks to vm1,
there are many tx interrupts in vm2.
with the patch applied there are just a few tx interrupts.

v2-&gt;v3:
-update the interrupt disable flag even with the event_triggered is set,
-instead of checking whether event_triggered is set in
-virtqueue_get_buf_ctx_{packed/split}, will cause the drivers  which have
-not called virtqueue_{enable/disable}_cb to miss notifications.

v3-&gt;v4:
-remove change for
-"if (vq-&gt;packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE)"
-in virtqueue_disable_cb_packed

Fixes: 8d622d21d248 ("virtio: fix up virtio_disable_cb")
Signed-off-by: Albert Huang &lt;huangjie.albert@bytedance.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: Jason Wang &lt;jasowang@redhat.com&gt;
Message-Id: &lt;20230329102300.61000-1-huangjie.albert@bytedance.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>virtio_pci: modify ENOENT to EINVAL</title>
<updated>2023-01-24T06:24:31Z</updated>
<author>
<name>Angus Chen</name>
<email>angus.chen@jaguarmicro.com</email>
</author>
<published>2022-11-01T11:16:54Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=ab23a6dbfc7232a6d5b6baff781ad1f3d32dbdb0'/>
<id>urn:sha1:ab23a6dbfc7232a6d5b6baff781ad1f3d32dbdb0</id>
<content type='text'>
[ Upstream commit b66ead2d0ecac00c3a06a6218af5411cb5fcb5d5 ]

Virtio_crypto use max_data_queues+1 to setup vqs,
we use vp_modern_get_num_queues to protect the vq range in setup_vq.
We could enter index &gt;= vp_modern_get_num_queues(mdev) in setup_vq
if common-&gt;num_queues is not set well,and it return -ENOENT.
It is better to use -EINVAL instead.

Signed-off-by: Angus Chen &lt;angus.chen@jaguarmicro.com&gt;
Message-Id: &lt;20221101111655.1947-1-angus.chen@jaguarmicro.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>virtio_pci: use irq to detect interrupt support</title>
<updated>2022-10-13T13:33:03Z</updated>
<author>
<name>Michael S. Tsirkin</name>
<email>mst@redhat.com</email>
</author>
<published>2022-10-12T21:58:28Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=2145ab513e3b3f910bd4a93abbdfa74fc65dfea4'/>
<id>urn:sha1:2145ab513e3b3f910bd4a93abbdfa74fc65dfea4</id>
<content type='text'>
commit 71491c54eafa ("virtio_pci: don't try to use intxif pin is zero")
breaks virtio_pci on powerpc, when running as a qemu guest.

vp_find_vqs() bails out because pci_dev-&gt;pin == 0.

But pci_dev-&gt;irq is populated correctly, so vp_find_vqs_intx() would
succeed if we called it - which is what the code used to do.

This seems to happen because pci_dev-&gt;pin is not populated in
pci_assign_irq(). A PCI core bug? Maybe.

However Linus said:
	I really think that that is basically the only time you should use
	that 'pci_dev-&gt;pin' thing: it basically exists not for "does this
	device have an IRQ", but for "what is the routing of this irq on this
	device".

and
	The correct way to check for "no irq" doesn't use NO_IRQ at all, it just does
		if (dev-&gt;irq) ...

so let's just check irq and be done with it.

Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Reported-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Fixes: 71491c54eafa ("virtio_pci: don't try to use intxif pin is zero")
Cc: "Angus Chen" &lt;angus.chen@jaguarmicro.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Tested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Acked-by: Jason Wang &lt;jasowang@redhat.com&gt;
Message-Id: &lt;20221012220312.308522-1-mst@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2022-10-11T00:53:04Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-10-11T00:53:04Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=27bc50fc90647bbf7b734c3fc306a5e61350da53'/>
<id>urn:sha1:27bc50fc90647bbf7b734c3fc306a5e61350da53</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
   linux-next for a couple of months without, to my knowledge, any
   negative reports (or any positive ones, come to that).

 - Also the Maple Tree from Liam Howlett. An overlapping range-based
   tree for vmas. It it apparently slightly more efficient in its own
   right, but is mainly targeted at enabling work to reduce mmap_lock
   contention.

   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.

   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   at [1]. This has yet to be addressed due to Liam's unfortunately
   timed vacation. He is now back and we'll get this fixed up.

 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
   clang-generated instrumentation to detect used-unintialized bugs down
   to the single bit level.

   KMSAN keeps finding bugs. New ones, as well as the legacy ones.

 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.

 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
   support file/shmem-backed pages.

 - userfaultfd updates from Axel Rasmussen

 - zsmalloc cleanups from Alexey Romanov

 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
   memory-failure

 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.

 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.

 - memcg cleanups from Kairui Song.

 - memcg fixes and cleanups from Johannes Weiner.

 - Vishal Moola provides more folio conversions

 - Zhang Yi removed ll_rw_block() :(

 - migration enhancements from Peter Xu

 - migration error-path bugfixes from Huang Ying

 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths. For optimizations by PMEM drivers, DRM
   drivers, etc.

 - vma merging improvements from Jakub Matěn.

 - NUMA hinting cleanups from David Hildenbrand.

 - xu xin added aditional userspace visibility into KSM merging
   activity.

 - THP &amp; KSM code consolidation from Qi Zheng.

 - more folio work from Matthew Wilcox.

 - KASAN updates from Andrey Konovalov.

 - DAMON cleanups from Kaixu Xia.

 - DAMON work from SeongJae Park: fixes, cleanups.

 - hugetlb sysfs cleanups from Muchun Song.

 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.

Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]

* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
  hugetlb: allocate vma lock for all sharable vmas
  hugetlb: take hugetlb vma_lock when clearing vma_lock-&gt;vma pointer
  hugetlb: fix vma lock handling during split vma and range unmapping
  mglru: mm/vmscan.c: fix imprecise comments
  mm/mglru: don't sync disk for each aging cycle
  mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
  mm: memcontrol: use do_memsw_account() in a few more places
  mm: memcontrol: deprecate swapaccounting=0 mode
  mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
  mm/secretmem: remove reduntant return value
  mm/hugetlb: add available_huge_pages() func
  mm: remove unused inline functions from include/linux/mm_inline.h
  selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
  selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
  selftests/vm: add thp collapse shmem testing
  selftests/vm: add thp collapse file and tmpfs testing
  selftests/vm: modularize thp collapse memory operations
  selftests/vm: dedup THP helpers
  mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
  mm/madvise: add file and shmem support to MADV_COLLAPSE
  ...
</content>
</entry>
<entry>
<title>virtio_pci: don't try to use intxif pin is zero</title>
<updated>2022-10-08T00:00:44Z</updated>
<author>
<name>Angus Chen</name>
<email>angus.chen@jaguarmicro.com</email>
</author>
<published>2022-09-30T00:09:15Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=71491c54eafa318fdd24a1f26a1c82b28e1ac21d'/>
<id>urn:sha1:71491c54eafa318fdd24a1f26a1c82b28e1ac21d</id>
<content type='text'>
The background is that we use dpu in cloud computing,the arch is x86,80
cores. We will have a lots of virtio devices,like 512 or more.
When we probe about 200 virtio_blk devices,it will fail and
the stack is printed as follows:

[25338.485128] virtio-pci 0000:b3:00.0: virtio_pci: leaving for legacy driver
[25338.496174] genirq: Flags mismatch irq 0. 00000080 (virtio418) vs. 00015a00 (timer)
[25338.503822] CPU: 20 PID: 5431 Comm: kworker/20:0 Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-305.30.1.el8.x86_64
[25338.516403] Hardware name: Inspur NF5280M5/YZMB-00882-10E, BIOS 4.1.21 08/25/2021
[25338.523881] Workqueue: events work_for_cpu_fn
[25338.528235] Call Trace:
[25338.530687]  dump_stack+0x5c/0x80
[25338.534000]  __setup_irq.cold.53+0x7c/0xd3
[25338.538098]  request_threaded_irq+0xf5/0x160
[25338.542371]  vp_find_vqs+0xc7/0x190
[25338.545866]  init_vq+0x17c/0x2e0 [virtio_blk]
[25338.550223]  ? ncpus_cmp_func+0x10/0x10
[25338.554061]  virtblk_probe+0xe6/0x8a0 [virtio_blk]
[25338.558846]  virtio_dev_probe+0x158/0x1f0
[25338.562861]  really_probe+0x255/0x4a0
[25338.566524]  ? __driver_attach_async_helper+0x90/0x90
[25338.571567]  driver_probe_device+0x49/0xc0
[25338.575660]  bus_for_each_drv+0x79/0xc0
[25338.579499]  __device_attach+0xdc/0x160
[25338.583337]  bus_probe_device+0x9d/0xb0
[25338.587167]  device_add+0x418/0x780
[25338.590654]  register_virtio_device+0x9e/0xe0
[25338.595011]  virtio_pci_probe+0xb3/0x140
[25338.598941]  local_pci_probe+0x41/0x90
[25338.602689]  work_for_cpu_fn+0x16/0x20
[25338.606443]  process_one_work+0x1a7/0x360
[25338.610456]  ? create_worker+0x1a0/0x1a0
[25338.614381]  worker_thread+0x1cf/0x390
[25338.618132]  ? create_worker+0x1a0/0x1a0
[25338.622051]  kthread+0x116/0x130
[25338.625283]  ? kthread_flush_work_fn+0x10/0x10
[25338.629731]  ret_from_fork+0x1f/0x40
[25338.633395] virtio_blk: probe of virtio418 failed with error -16

The log :
"genirq: Flags mismatch irq 0. 00000080 (virtio418) vs. 00015a00 (timer)"
was printed because of the irq 0 is used by timer exclusive,and when
vp_find_vqs call vp_find_vqs_msix and returns false twice (for
whatever reason), then it will call vp_find_vqs_intx as a fallback.
Because vp_dev-&gt;pci_dev-&gt;irq is zero, we request irq 0 with
flag IRQF_SHARED, and get a backtrace like above.

According to PCI spec about "Interrupt Pin" Register (Offset 3Dh):
"The Interrupt Pin register is a read-only register that identifies the
 legacy interrupt Message(s) the Function uses. Valid values are 01h, 02h,
 03h, and 04h that map to legacy interrupt Messages for INTA,
 INTB, INTC, and INTD respectively. A value of 00h indicates that the
 Function uses no legacy interrupt Message(s)."

So if vp_dev-&gt;pci_dev-&gt;pin is zero, we should not request legacy
interrupt.

Signed-off-by: Angus Chen &lt;angus.chen@jaguarmicro.com&gt;
Suggested-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Message-Id: &lt;20220930000915.548-1-angus.chen@jaguarmicro.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
</content>
</entry>
</feed>
