linux.git/include/linux/virtio_config.h, branch v6.1

virtio: kerneldocs fixes and enhancements

2022-08-16T05:40:24+00:00

Fix variable names in some kerneldocs, naming in others.
Add kerneldocs for struct vring_desc and vring_interrupt.

Signed-off-by: Ricardo Cañuelo 
Message-Id: <20220810094004.1250-2-ricardo.canuelo@collabora.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck

virtio: Revert "virtio: find_vqs() add arg sizes"

2022-08-16T05:40:24+00:00

This reverts commit a10fba0377145fccefea4dc4dd5915b7ed87e546: the
proposed API isn't supported on all transports but no
effort was made to address this.

It might not be hard to fix if we want to: maybe just
rename size to size_hint and make sure legacy
transports ignore the hint.

But it's not sure what the benefit is in any case, so
let's drop it.

Fixes: a10fba037714 ("virtio: find_vqs() add arg sizes")
Signed-off-by: Michael S. Tsirkin 
Message-Id: <20220816053602.173815-8-mst@redhat.com>

virtio: Revert "virtio: add helper virtio_find_vqs_ctx_size()"

2022-08-16T05:38:28+00:00

This reverts commit fe3dc04e31aa51f91dc7f741a5f76cc4817eb5b4: the
API is now unused and in fact can't be implemented on top of a legacy
device.

Fixes: fe3dc04e31aa ("virtio: add helper virtio_find_vqs_ctx_size()")
Cc: "Xuan Zhuo" 
Signed-off-by: Michael S. Tsirkin 
Message-Id: <20220816053602.173815-3-mst@redhat.com>

virtio: add helper virtio_find_vqs_ctx_size()

2022-08-11T08:06:41+00:00

Introduce helper virtio_find_vqs_ctx_size() to call find_vqs and specify
the maximum size of each vq ring.

Signed-off-by: Xuan Zhuo 
Acked-by: Jason Wang 
Message-Id: <20220801063902.129329-37-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin

virtio: find_vqs() add arg sizes

2022-08-11T08:06:40+00:00

find_vqs() adds a new parameter sizes to specify the size of each vq
vring.

NULL as sizes means that all queues in find_vqs() use the maximum size.
A value in the array is 0, which means that the corresponding queue uses
the maximum size.

In the split scenario, the meaning of size is the largest size, because
it may be limited by memory, the virtio core will try a smaller size.
And the size is power of 2.

Signed-off-by: Xuan Zhuo 
Acked-by: Hans de Goede 
Reviewed-by: Mathieu Poirier 
Acked-by: Jason Wang 
Message-Id: <20220801063902.129329-34-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin

virtio: struct virtio_config_ops add callbacks for queue_reset

2022-08-11T08:06:38+00:00

reset can be divided into the following four steps (example):
 1. transport: notify the device to reset the queue
 2. vring:     recycle the buffer submitted
 3. vring:     reset/resize the vring (may re-alloc)
 4. transport: mmap vring to device, and enable the queue

In order to support queue reset, add two callbacks in struct
virtio_config_ops to implement steps 1 and 4.

Signed-off-by: Xuan Zhuo 
Acked-by: Jason Wang 
Message-Id: <20220801063902.129329-3-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin

virtio: disable notification hardening by default

2022-06-24T06:49:48+00:00

We try to harden virtio device notifications in 8b4ec69d7e09 ("virtio:
harden vring IRQ"). It works with the assumption that the driver or
core can properly call virtio_device_ready() at the right
place. Unfortunately, this seems to be not true and uncover various
bugs of the existing drivers, mainly the issue of using
virtio_device_ready() incorrectly.

So let's add a Kconfig option and disable it by default. It gives
us time to fix the drivers and then we can consider re-enabling it.

Signed-off-by: Jason Wang 
Message-Id: <20220622012940.21441-1-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck

virtio: replace arch_has_restricted_virtio_memory_access()

2022-06-06T06:22:01+00:00

Instead of using arch_has_restricted_virtio_memory_access() together
with CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, replace those
with platform_has() and a new platform feature
PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS.

Signed-off-by: Juergen Gross 
Reviewed-by: Oleksandr Tyshchenko 
Tested-by: Oleksandr Tyshchenko  # Arm64 only
Reviewed-by: Christoph Hellwig 
Acked-by: Borislav Petkov

virtio: use WARN_ON() to warning illegal status value

2022-05-31T16:45:10+00:00

We used to use BUG_ON() in virtio_device_ready() to detect illegal
status value, this seems sub-optimal since the value is under the
control of the device. Switch to use WARN_ON() instead.

Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: "Paul E. McKenney" 
Cc: Marc Zyngier 
Cc: Halil Pasic 
Cc: Cornelia Huck 
Cc: Vineeth Vijayan 
Cc: Peter Oberparleiter 
Cc: linux-s390@vger.kernel.org
Signed-off-by: Jason Wang 
Message-Id: <20220527060120.20964-10-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Xuan Zhuo

virtio: harden vring IRQ

2022-05-31T16:45:10+00:00

This is a rework on the previous IRQ hardening that is done for
virtio-pci where several drawbacks were found and were reverted:

1) try to use IRQF_NO_AUTOEN which is not friendly to affinity managed IRQ
   that is used by some device such as virtio-blk
2) done only for PCI transport

The vq->broken is re-used in this patch for implementing the IRQ
hardening. The vq->broken is set to true during both initialization
and reset. And the vq->broken is set to false in
virtio_device_ready(). Then vring_interrupt() can check and return
when vq->broken is true. And in this case, switch to return IRQ_NONE
to let the interrupt core aware of such invalid interrupt to prevent
IRQ storm.

The reason of using a per queue variable instead of a per device one
is that we may need it for per queue reset hardening in the future.

Note that the hardening is only done for vring interrupt since the
config interrupt hardening is already done in commit 22b7050a024d7
("virtio: defer config changed notifications"). But the method that is
used by config interrupt can't be reused by the vring interrupt
handler because it uses spinlock to do the synchronization which is
expensive.

Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: "Paul E. McKenney" 
Cc: Marc Zyngier 
Cc: Halil Pasic 
Cc: Cornelia Huck 
Cc: Vineeth Vijayan 
Cc: Peter Oberparleiter 
Cc: linux-s390@vger.kernel.org
Signed-off-by: Jason Wang 
Message-Id: <20220527060120.20964-9-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Xuan Zhuo