linux.git/drivers/virtio, branch v6.5-rc2

virtio: allow caller to override device DMA mask in vp_modern

2023-06-27T14:47:08+00:00

To add a bit of vendor flexibility with various virtio based devices,
allow the caller to specify a different DMA mask.  This adds a dma_mask
field to struct virtio_pci_modern_device.  If defined by the driver,
this mask will be used in a call to dma_set_mask_and_coherent() instead
of the traditional DMA_BIT_MASK(64).  This allows limiting the DMA space
on vendor devices with address limitations.

Signed-off-by: Shannon Nelson 
Acked-by: Jason Wang 
Message-Id: <20230519215632.12343-3-shannon.nelson@amd.com>
Signed-off-by: Michael S. Tsirkin

virtio: allow caller to override device id in vp_modern

2023-06-27T14:47:08+00:00

To add a bit of vendor flexibility with various virtio based devices,
allow the caller to check for a different device id.  This adds a function
pointer field to struct virtio_pci_modern_device to specify an override
device id check.  If defined by the driver, this function will be called
to check that the PCI device is the vendor's expected device, and will
return the found device id to be stored in mdev->id.device.  This allows
vendors with alternative vendor device ids to use this library on their
own device BAR.

Note: A lot of the diff in this is simply indenting the existing code
into an else block.

Signed-off-by: Shannon Nelson 
Acked-by: Jason Wang 
Message-Id: <20230519215632.12343-2-shannon.nelson@amd.com>
Signed-off-by: Michael S. Tsirkin

virtio_pci: Optimize virtio_pci_device structure size

2023-06-27T14:47:08+00:00

Improve the size of the virtio_pci_device structure, which is commonly
used to represent a virtio PCI device. A given virtio PCI device can
either of legacy type or modern type, with the
struct virtio_pci_legacy_device occupying 32 bytes and the
struct virtio_pci_modern_device occupying 88 bytes. Make them a union,
thereby save 32 bytes of memory as shown by the pahole tool. This
improvement is particularly beneficial when dealing with numerous
devices, as it helps conserve memory resources.

Before the modification, pahole tool reported the following:
struct virtio_pci_device {
[...]
        struct virtio_pci_legacy_device ldev;            /*   824    32 */
        /* --- cacheline 13 boundary (832 bytes) was 24 bytes ago --- */
        struct virtio_pci_modern_device mdev;            /*   856    88 */

        /* XXX last struct has 4 bytes of padding */
[...]
        /* size: 1056, cachelines: 17, members: 19 */
[...]
};

After the modification, pahole tool reported the following:
struct virtio_pci_device {
[...]
        union {
                struct virtio_pci_legacy_device ldev;    /*   824    32 */
                struct virtio_pci_modern_device mdev;    /*   824    88 */
        };                                               /*   824    88 */
[...]
	/* size: 1024, cachelines: 16, members: 18 */
[...]
};

Signed-off-by: Feng Liu 
Reviewed-by: Jiri Pirko 
Message-Id: <20230516135446.16266-1-feliu@nvidia.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Xuan Zhuo 
Acked-by: Jason Wang

virtio-vdpa: Fix unchecked call to NULL set_vq_affinity

2023-06-27T14:47:08+00:00

The referenced patch calls set_vq_affinity without checking if the op is
valid. This patch adds the check.

Fixes: 3dad56823b53 ("virtio-vdpa: Support interrupt affinity spreading mechanism")
Reviewed-by: Gal Pressman 
Signed-off-by: Dragos Tatulea 
Message-Id: <20230504135053.2283816-1-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Feng Liu

Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-04-28T02:42:02+00:00

Pull MM updates from Andrew Morton:

- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.

- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.

- zsmalloc performance improvements from Sergey Senozhatsky.

- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.

- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful

- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.

- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.

- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).

- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.

- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.

- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.

- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.

- Cleanups to do_fault_around() by Lorenzo Stoakes.

- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.

- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.

- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.

- Lorenzo has also contributed further cleanups of vma_merge().

- Chaitanya Prakash provides some fixes to the mmap selftesting code.

- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.

- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.

- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.

- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.

- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.

- Yosry Ahmed has improved the performance of memcg statistics
flushing.

- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.

- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.

- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.

- Pankaj Raghav has made page_endio() unneeded and has removed it.

- Peter Xu contributed some rationalizations of the userfaultfd
selftests.

- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.

- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.

- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.

- Peter Xu fixes a few issues with uffd-wp at fork() time.

- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.

* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2023-04-28T00:05:34+00:00

Pull virtio updates from Michael Tsirkin:
 "virtio,vhost,vdpa: features, fixes, and cleanups:

   - reduction in interrupt rate in virtio

   - perf improvement for VDUSE

   - scalability for vhost-scsi

   - non power of 2 ring support for packed rings

   - better management for mlx5 vdpa

   - suspend for snet

   - VIRTIO_F_NOTIFICATION_DATA

   - shared backend with vdpa-sim-blk

   - user VA support in vdpa-sim

   - better struct packing for virtio

  and fixes, cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (52 commits)
  vhost_vdpa: fix unmap process in no-batch mode
  MAINTAINERS: make me a reviewer of VIRTIO CORE AND NET DRIVERS
  tools/virtio: fix build caused by virtio_ring changes
  virtio_ring: add a struct device forward declaration
  vdpa_sim_blk: support shared backend
  vdpa_sim: move buffer allocation in the devices
  vdpa/snet: use likely/unlikely macros in hot functions
  vdpa/snet: implement kick_vq_with_data callback
  virtio-vdpa: add VIRTIO_F_NOTIFICATION_DATA feature support
  virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
  vdpa/snet: support the suspend vDPA callback
  vdpa/snet: support getting and setting VQ state
  MAINTAINERS: add vringh.h to Virtio Core and Net Drivers
  vringh: address kdoc warnings
  vdpa: address kdoc warnings
  virtio_ring: don't update event idx on get_buf
  vdpa_sim: add support for user VA
  vdpa_sim: replace the spinlock with a mutex to protect the state
  vdpa_sim: use kthread worker
  vdpa_sim: make devices agnostic for work management
  ...

virtio-vdpa: add VIRTIO_F_NOTIFICATION_DATA feature support

2023-04-21T07:02:35+00:00

Add VIRTIO_F_NOTIFICATION_DATA support for vDPA transport.
If this feature is negotiated, the driver passes extra data when kicking
a virtqueue.

A device that offers this feature needs to implement the
kick_vq_with_data callback.

kick_vq_with_data receives the vDPA device and data.
data includes:
16 bits vqn and 16 bits next available index for split virtqueues.
16 bits vqs, 15 least significant bits of next available index
and 1 bit next_wrap for packed virtqueues.

This patch follows a patch [1] by Viktor Prutyanov which adds support
for the MMIO, channel I/O and modern PCI transports.

Signed-off-by: Alvaro Karsz 
Message-Id: <20230413081855.36643-3-alvaro.karsz@solid-run.com>
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang

virtio: add VIRTIO_F_NOTIFICATION_DATA feature support

2023-04-21T07:02:35+00:00

According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
indicates that the driver passes extra data along with the queue
notifications.

In a split queue case, the extra data is 16-bit available index. In a
packed queue case, the extra data is 1-bit wrap counter and 15-bit
available index.

Add support for this feature for MMIO, channel I/O and modern PCI
transports.

Signed-off-by: Viktor Prutyanov 
Acked-by: Jason Wang 
Reviewed-by: Xuan Zhuo 
Message-Id: <20230413081855.36643-2-alvaro.karsz@solid-run.com>
Signed-off-by: Michael S. Tsirkin

virtio_ring: don't update event idx on get_buf

2023-04-21T07:02:34+00:00

In virtio_net, if we disable napi_tx, when we trigger a tx interrupt,
the vq->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(&vq->split.vring) or vq->packed.vring.driver->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 -----------------> 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->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->v4:
-remove change for
-"if (vq->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 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Jason Wang 
Message-Id: <20230329102300.61000-1-huangjie.albert@bytedance.com>
Signed-off-by: Michael S. Tsirkin

vdpa: Add eventfd for the vdpa callback

2023-04-21T07:02:32+00:00

Add eventfd for the vdpa callback so that user
can signal it directly instead of triggering the
callback. It will be used for vhost-vdpa case.

Signed-off-by: Xie Yongji 
Message-Id: <20230323053043.35-9-xieyongji@bytedance.com>
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang