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Add virtqueue_add_inbuf_cache_clean() for passing DMA_ATTR_CPU_CACHE_CLEAN
to virtqueue operations. This suppresses DMA debug cacheline overlap
warnings for buffers where proper cache management is ensured by the
caller.
Message-ID: <e50d38c974859e731e50bda7a0ee5691debf5bc4.1767601130.git.mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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This patch implements in order support for both split virtqueue and
packed virtqueue. Performance could be gained for the device where the
memory access could be expensive (e.g vhost-net or a real PCI device):
Benchmark with KVM guest:
Vhost-net on the host: (pktgen + XDP_DROP):
in_order=off | in_order=on | +%
TX: 4.51Mpps | 5.30Mpps | +17%
RX: 3.47Mpps | 3.61Mpps | + 4%
Vhost-user(testpmd) on the host: (pktgen/XDP_DROP):
For split virtqueue:
in_order=off | in_order=on | +%
TX: 5.60Mpps | 5.60Mpps | +0.0%
RX: 9.16Mpps | 9.61Mpps | +4.9%
For packed virtqueue:
in_order=off | in_order=on | +%
TX: 5.60Mpps | 5.70Mpps | +1.7%
RX: 10.6Mpps | 10.8Mpps | +1.8%
Benchmark also shows no performance impact for in_order=off for queue
size with 256 and 1024.
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-20-jasowang@redhat.com>
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This patch factors out the split core detaching logic that could be
reused by in order feature into a dedicated function.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-19-jasowang@redhat.com>
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Factor out the split indirect descriptor detaching logic in order to
allow it to be reused by the in order support.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-18-jasowang@redhat.com>
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Factor out the core logic for updating last_used_idx to be reused by
the packed in order implementation.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-17-jasowang@redhat.com>
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Factor out core logic of buffer detaching and leave the free list
management to the caller so in_order can just call the core logic.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-16-jasowang@redhat.com>
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Let's determine the last descriptor by counting the number of sg. This
would be consistent with packed virtqueue implementation and ease the
future in-order implementation.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-15-jasowang@redhat.com>
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This patch introduces virtqueue ops which is a set of callbacks
that will be called for different queue layout or features. This would
help to avoid branches for split/packed and will ease the future
implementation like in order.
Note that in order to eliminate the indirect calls this patch uses
global array of const ops to allow compiler to avoid indirect
branches.
Tested with CONFIG_MITIGATION_RETPOLINE, no performance differences
were noticed.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-14-jasowang@redhat.com>
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Switch to use unsigned int for virtqueue_poll_packed() to match
virtqueue_poll() and virtqueue_poll_split() and to ease the
abstraction of the virtqueue ops.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-13-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-12-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-11-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-10-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-9-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-8-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-7-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-6-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-5-jasowang@redhat.com>
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This patch unifies the logic of virtqueue_poll() and more_used() for
better code reusing and ease the future in order implementation.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-4-jasowang@redhat.com>
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Those variants are used internally so let's switch to use
vring_virtqueue as parameter to be consistent with other internal
virtqueue helpers.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-3-jasowang@redhat.com>
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To be consistent with virtqueue_reset().
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251230064649.55597-2-jasowang@redhat.com>
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Since the return value of vring_unmap_one_split() is exactly
vq->split.desc_extra[i].next, 'i = vq->split.desc_extra[i].next' is
redundant. Assign vring_unmap_one_split() to i instead.
Since vq->split.desc_extra is assigned to extra, use extra[i].next
instead of vq->split.desc_extra[i].next to improve readability.
No change in functionality.
Signed-off-by: zhangdongchuan <zhangdongchuan@eswincomputing.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <202511261140162936986@eswincomputing.com>
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Documentation build reported:
WARNING: ./drivers/virtio/virtio_ring.c:3174 function parameter 'vaddr' not described in 'virtqueue_map_free_coherent'
WARNING: ./drivers/virtio/virtio_ring.c:3308 expecting prototype for virtqueue_mapping_error(). Prototype was for virtqueue_map_mapping_error() instead
The kernel-doc block for virtqueue_map_free_coherent() omitted the @vaddr parameter, and
the kernel-doc header for virtqueue_map_mapping_error() used the wrong function name
(virtqueue_mapping_error) instead of the actual function name.
This change updates:
- the function name in the comment to virtqueue_map_mapping_error()
- adds the missing @vaddr description in the comment for virtqueue_map_free_coherent()
Fixes: b41cb3bcf67f ("virtio: rename dma helpers")
Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251110202920.2250244-1-kriish.sharma2006@gmail.com>
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Pull virtio updates from Michael Tsirkin:
"Just fixes and cleanups this time around. The mapping cleanups are
preparing the ground for new features, though"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio-vdpa: Drop redundant conversion to bool
vduse: Use fixed 4KB bounce pages for non-4KB page size
vduse: switch to use virtio map API instead of DMA API
vdpa: introduce map ops
vdpa: support virtio_map
virtio: introduce map ops in virtio core
virtio_ring: rename dma_handle to map_handle
virtio: introduce virtio_map container union
virtio: rename dma helpers
virtio_ring: switch to use dma_{map|unmap}_page()
virtio_ring: constify virtqueue pointer for DMA helpers
virtio_balloon: Remove redundant __GFP_NOWARN
vhost: vringh: Fix copy_to_iter return value check
vhost: vringh: Modify the return value check
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This patch introduces map operations for virtio device. Virtio used to
use DMA API which is not necessarily the case since some devices
doesn't do DMA. Instead of using tricks and abusing DMA API, let's
simply abstract the current mapping logic into a virtio specific
mapping operations. For the device or transport that doesn't do DMA,
they can implement their own mapping logic without the need to trick
DMA core. In this case the mapping metadata is opaque to the virtio
core that will be passed back to the transport or device specific map
operations. For other devices, DMA API will still be used, so map
token will still be the dma device to minimize the changeset and
performance impact.
The mapping operations are abstracted as a independent structure
instead of reusing virtio_config_ops. This allows the transport can
simply reuse the structure for lower layers like vDPA.
A set of new mapping helpers were introduced for the device that want
to do mapping by themselves.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-7-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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Following patch will introduce virtio map operations which means the
address is not necessarily used for DMA. Let's rename the dma_handle
to map_handle first.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-6-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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Following patch will introduce the mapping operations for virtio
device. In order to achieve this, besides the dma device, virtio core
needs to support a transport or device specific mapping metadata as well.
So this patch introduces a union container of a dma device. The idea
is the allow the transport layer to pass device specific mapping
metadata which will be used as a parameter for the virtio mapping
operations. For the transport or device that is using DMA, dma device
is still being used.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-5-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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Following patch will introduce virtio mapping function to avoid
abusing DMA API for device that doesn't do DMA. To ease the
introduction, this patch rename "dma" to "map" for the current dma
mapping helpers.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-4-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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This patch switches to use dma_{map|unmap}_page() to reduce the
coverage of DMA operations. This would help for the following rework
on the virtio map operations.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-3-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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This patch constifies the virtqueue pointer for DMA helpers.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20250821064641.5025-2-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
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Convert the KMSAN DMA handling function from page-based to physical
address-based interface.
The refactoring renames kmsan_handle_dma() parameters from accepting
(struct page *page, size_t offset, size_t size) to (phys_addr_t phys,
size_t size). The existing semantics where callers are expected to
provide only kmap memory is continued here.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/3557cbaf66e935bc794f37d2b891ef75cbf2c80c.1757423202.git.leonro@nvidia.com
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drivers handle ENOSPC specially since it's an error one can
get from a working VQ. Document the semantics.
Message-Id: <2e6ec46b8d5e6755be291cec8e2ec57ef286e97b.1748356035.git.mst@redhat.com>
Reported-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
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The virtqueue_resize() function was not correctly propagating error codes
from its internal resize helper functions, specifically
virtqueue_resize_packet() and virtqueue_resize_split(). If these helpers
returned an error, but the subsequent call to virtqueue_enable_after_reset()
succeeded, the original error from the resize operation would be masked.
Consequently, virtqueue_resize() could incorrectly report success to its
caller despite an underlying resize failure.
This change restores the original code behavior:
if (vdev->config->enable_vq_after_reset(_vq))
return -EBUSY;
return err;
Fix: commit ad48d53b5b3f ("virtio_ring: separate the logic of reset/enable from virtqueue_resize")
Cc: xuanzhuo@linux.alibaba.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20250521092236.661410-2-lvivier@redhat.com
Tested-by: Lei Yang <leiyang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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syzbot reports a data-race when accessing the event_triggered, here is the
simplified stack when the issue occurred:
==================================================================
BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed
write to 0xffff8881025bc452 of 1 bytes by task 3288 on cpu 0:
virtqueue_enable_cb_delayed+0x42/0x3c0 drivers/virtio/virtio_ring.c:2653
start_xmit+0x230/0x1310 drivers/net/virtio_net.c:3264
__netdev_start_xmit include/linux/netdevice.h:5151 [inline]
netdev_start_xmit include/linux/netdevice.h:5160 [inline]
xmit_one net/core/dev.c:3800 [inline]
read to 0xffff8881025bc452 of 1 bytes by interrupt on cpu 1:
virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:880 [inline]
virtqueue_disable_cb+0x92/0x180 drivers/virtio/virtio_ring.c:2566
skb_xmit_done+0x5f/0x140 drivers/net/virtio_net.c:777
vring_interrupt+0x161/0x190 drivers/virtio/virtio_ring.c:2715
__handle_irq_event_percpu+0x95/0x490 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
value changed: 0x01 -> 0x00
==================================================================
When the data race occurs, the function virtqueue_enable_cb_delayed() sets
event_triggered to false, and virtqueue_disable_cb_split/packed() reads it
as false due to the race condition. Since event_triggered is an unreliable
hint used for optimization, this should only cause the driver temporarily
suggest that the device not send an interrupt notification when the event
index is used.
Fix this KCSAN reported data-race issue by explicitly tagging the access as
data_racy.
Reported-by: syzbot+efe683d57990864b8c8e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67c7761a.050a0220.15b4b9.0018.GAE@google.com/
Signed-off-by: Zhongqiu Han <quic_zhonhan@quicinc.com>
Message-Id: <20250312130412.3516307-1-quic_zhonhan@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
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When virtqueue_reset() has actually recycled all unused buffers,
additional work may be required in some cases. Relying solely on its
return status is fragile, so introduce a new function argument
'recycle_done', which is invoked when it really occurs.
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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When virtqueue_resize() has actually recycled all unused buffers,
additional work may be required in some cases. Relying solely on its
return status is fragile, so introduce a new function argument
'recycle_done', which is invoked when the recycle really occurs.
Cc: <stable@vger.kernel.org> # v6.11+
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Pull virtio updates from Michael Tsirkin:
"A small number of improvements all over the place"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio_vdpa: remove redundant check on desc
virtio_fs: store actual queue index in mq_map
virtio_fs: add informative log for new tag discovery
virtio: Make vring_new_virtqueue support packed vring
virtio_pmem: Add freeze/restore callbacks
vdpa/mlx5: Fix suboptimal range on iotlb iteration
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Now, this API is useless. remove it.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-8-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Two APIs are introduced to submit premapped per-buffers.
int virtqueue_add_inbuf_premapped(struct virtqueue *vq,
struct scatterlist *sg, unsigned int num,
void *data,
void *ctx,
gfp_t gfp);
int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
struct scatterlist *sg, unsigned int num,
void *data,
gfp_t gfp);
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-6-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The current configuration sets the virtqueue (vq) to premapped mode,
implying that all buffers submitted to this queue must be mapped ahead
of time. This presents a challenge for the virtnet send queue (sq): the
virtnet driver would be required to keep track of dma information for vq
size * 17, which can be substantial. However, if the premapped mode were
applied on a per-buffer basis, the complexity would be greatly reduced.
With AF_XDP enabled, AF_XDP buffers would become premapped, while kernel
skb buffers could remain unmapped.
And consider that some sgs are not generated by the virtio driver,
that may be passed from the block stack. So we can not change the
sgs, new APIs are the better way.
So we pass the new argument 'premapped' to indicate the buffers
submitted to virtio are premapped in advance. Additionally,
DMA unmap operations for these buffers will be bypassed.
Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-5-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The subsequent commit needs to know whether every indirect buffer is
premapped or not. So we need to introduce an extra struct for every
indirect buffer to record this info.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-4-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The subsequent commit needs to know whether every indirect buffer is
premapped or not. So we need to introduce an extra struct for every
indirect buffer to record this info.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-3-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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To make the code readable, introduce vring_need_unmap_buffer() to
replace do_unmap.
use_dma_api premapped -> vring_need_unmap_buffer()
1. false false false
2. true false true
3. true true false
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-2-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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It is used for testing in tools/virtio/vringh_test.c.
If vring_new_virtqueue supports packed vring, we can add support for
packed vring to vringh and test it.
Signed-off-by: Wenyu Huang <huangwenyu1998@gmail.com>
Message-Id: <20241013033233.65026-1-huangwenyu1998@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
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Setting event_triggered from the interrupt handler
is fundamentally racy. There are races of 2 types:
1. vq processing can read false value while interrupt
triggered and set it to true.
result will be a bit of extra work when disabling cbs, no big deal.
1. vq processing can set false value then interrupt
immediately sets true value
since interrupt then triggers a callback which will
process buffers, this is also not an issue.
However, looks like KCSAN can not figure all this out, and warns about
the race between the write and the read. Tag the access data_racy for
now. We should probably look at ways to make this more
straight-forwardly correct.
Message-ID: <6bdd771a4fb7625a9227971b3cf4745c34c31a32.1726153334.git.mst@redhat.com>
Reported-by: syzbot+8a02104389c2e0ef5049@syzkaller.appspotmail.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Marco Elver <elver@google.com>
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With ARCH=sh, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/virtio/virtio.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/virtio/virtio_ring.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Message-Id: <20240702-md-sh-drivers-virtio-v1-1-cf7325ab6ccc@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Add kmsan for virtqueue_dma_map_single_attrs to fix:
BUG: KMSAN: uninit-value in receive_buf+0x45ca/0x6990
receive_buf+0x45ca/0x6990
virtnet_poll+0x17e0/0x3130
net_rx_action+0x832/0x26e0
handle_softirqs+0x330/0x10f0
[...]
Uninit was created at:
__alloc_pages_noprof+0x62a/0xe60
alloc_pages_noprof+0x392/0x830
skb_page_frag_refill+0x21a/0x5c0
virtnet_rq_alloc+0x50/0x1500
try_fill_recv+0x372/0x54c0
virtnet_open+0x210/0xbe0
__dev_open+0x56e/0x920
__dev_change_flags+0x39c/0x2000
dev_change_flags+0xaa/0x200
do_setlink+0x197a/0x7420
rtnl_setlink+0x77c/0x860
[...]
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Tested-by: Alexander Potapenko <glider@google.com>
Message-Id: <20240606111345.93600-1-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> # s390x
Acked-by: Jason Wang <jasowang@redhat.com>
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Now, we have virtio DMA APIs, the driver can be the premapped
mode whatever the virtio core uses dma api or not.
So remove the limit of checking use_dma_api from
virtqueue_set_dma_premapped().
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20240511031404.30903-2-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When use_dma_api and premapped are true, then the do_unmap is false.
Because the do_unmap is false, vring_unmap_extra_packed is not called by
detach_buf_packed.
if (unlikely(vq->do_unmap)) {
curr = id;
for (i = 0; i < state->num; i++) {
vring_unmap_extra_packed(vq,
&vq->packed.desc_extra[curr]);
curr = vq->packed.desc_extra[curr].next;
}
}
So the indirect desc table is not unmapped. This causes the unmap leak.
So here, we check vq->use_dma_api instead. Synchronously, dma info is
updated based on use_dma_api judgment
This bug does not occur, because no driver use the premapped with
indirect.
Fixes: b319940f83c2 ("virtio_ring: skip unmap for premapped")
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Message-Id: <20240223071833.26095-1-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Now the APIs virtqueue_dma_sync_single_range_for_{cpu,device} ignore
the parameter 'dir', that is a mistake.
[ 6.101666] ------------[ cut here ]------------
[ 6.102079] DMA-API: virtio-pci 0000:00:04.0: device driver syncs DMA memory with different direction [device address=0x00000000ae010000] [size=32752 bytes] [mapped with DMA_FROM_DEVICE] [synced with DMA_BIDIRECTIONAL]
[ 6.103630] WARNING: CPU: 6 PID: 0 at kernel/dma/debug.c:1125 check_sync+0x53e/0x6c0
[ 6.107420] CPU: 6 PID: 0 Comm: swapper/6 Tainted: G E 6.6.0+ #290
[ 6.108030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[ 6.108936] RIP: 0010:check_sync+0x53e/0x6c0
[ 6.109289] Code: 24 10 e8 f5 d9 74 00 4c 8b 4c 24 10 4c 8b 44 24 18 48 8b 4c 24 20 48 89 c6 41 56 4c 89 ea 48 c7 c7 b0 f1 50 82 e8 32 fc f3 ff <0f> 0b 48 c7 c7 48 4b 4a 82 e8 74 d9 fc ff 8b 73 4c 48 8d 7b 50 31
[ 6.110750] RSP: 0018:ffffc90000180cd8 EFLAGS: 00010092
[ 6.111178] RAX: 00000000000000ce RBX: ffff888100aa5900 RCX: 0000000000000000
[ 6.111744] RDX: 0000000000000104 RSI: ffffffff824c3208 RDI: 00000000ffffffff
[ 6.112316] RBP: ffffc90000180d40 R08: 0000000000000000 R09: 00000000fffeffff
[ 6.112893] R10: ffffc90000180b98 R11: ffffffff82f63308 R12: ffffffff83d5af00
[ 6.113460] R13: ffff888100998200 R14: ffffffff824a4b5f R15: 0000000000000286
[ 6.114027] FS: 0000000000000000(0000) GS:ffff88842fd80000(0000) knlGS:0000000000000000
[ 6.114665] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 6.115128] CR2: 00007f10f1e03030 CR3: 0000000108272004 CR4: 0000000000770ee0
[ 6.115701] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 6.116272] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 6.116842] PKRU: 55555554
[ 6.117069] Call Trace:
[ 6.117275] <IRQ>
[ 6.117452] ? __warn+0x84/0x140
[ 6.117727] ? check_sync+0x53e/0x6c0
[ 6.118034] ? __report_bug+0xea/0x100
[ 6.118353] ? check_sync+0x53e/0x6c0
[ 6.118653] ? report_bug+0x41/0xc0
[ 6.118944] ? handle_bug+0x3c/0x70
[ 6.119237] ? exc_invalid_op+0x18/0x70
[ 6.119551] ? asm_exc_invalid_op+0x1a/0x20
[ 6.119900] ? check_sync+0x53e/0x6c0
[ 6.120199] ? check_sync+0x53e/0x6c0
[ 6.120499] debug_dma_sync_single_for_cpu+0x5c/0x70
[ 6.120906] ? dma_sync_single_for_cpu+0xb7/0x100
[ 6.121291] virtnet_rq_unmap+0x158/0x170 [virtio_net]
[ 6.121716] virtnet_receive+0x196/0x220 [virtio_net]
[ 6.122135] virtnet_poll+0x48/0x1b0 [virtio_net]
[ 6.122524] __napi_poll+0x29/0x1b0
[ 6.123083] net_rx_action+0x282/0x360
[ 6.123612] __do_softirq+0xf3/0x2fb
[ 6.124138] __irq_exit_rcu+0x8e/0xf0
[ 6.124663] common_interrupt+0xbc/0xe0
[ 6.125202] </IRQ>
We need to enable CONFIG_DMA_API_DEBUG and work with need sync mode(such
as swiotlb) to reproduce this warn.
Fixes: 8bd2f71054bd ("virtio_ring: introduce dma sync api for virtqueue")
Reported-by: "Ning, Hongyu" <hongyu.ning@linux.intel.com>
Closes: https://lore.kernel.org/all/f37cb55a-6fc8-4e21-8789-46d468325eea@linux.intel.com/
Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Message-Id: <20231201033303.25141-1-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
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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->packed.vring.num.
Let’s assume the following situation:
vq->packed.vring.num=4
vq->packed.next_avail_idx: 1
vq->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->packed.next_avail_idx: 1
vq->packed.avail_wrap_counter: 1
But, the current implementation gives the following result:
vq->packed.next_avail_idx: 1
vq->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 <yuanyaogoog@chromium.org>
Message-Id: <20230808051110.3492693-1-yuanyaogoog@chromium.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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