The loop may exist if vq->broken is true,
virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split
will return NULL, so virtnet_poll will reschedule napi to
receive packet, it will lead cpu usage(si) to 100%.

call trace as below:
virtnet_poll
	virtnet_receive
		virtqueue_get_buf_ctx
			virtqueue_get_buf_ctx_packed
			virtqueue_get_buf_ctx_split
	virtqueue_napi_complete
		virtqueue_poll           //return true
		virtqueue_napi_schedule //it will reschedule napi

to fix this, return false if vq is broken in virtqueue_poll.
Signed-off-by: Mao Wenan <wenan.mao@linux.alibaba.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/1596354249-96204-1-git-send-email-wenan.mao@linux.alibaba.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

Speed and duplex config fields depend on VIRTIO_NET_F_SPEED_DUPLEX
which being 63>31 depends on VIRTIO_F_VERSION_1.

Accordingly, use LE accessors for these fields.
Reported-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

All drivers now use virtio_cread/write_le for LE config
space fields. Drop LE option from virtio_cread/write, only leaving
the option to access transitional fields.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio iommu is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio mem is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtgpu is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio pmem is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio crypto is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio fs is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Virtio input is modern-only. Use LE accessors for config space.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Balloon is LE, it's cleaner to access it as such directly.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Mirrors virtio_cread_feature but for LE fields.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

To be used by modern code, as well as to handle LE only fields such as
balloon.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

_Generic version allowed __uXX types but that is no longer necessary:

Transitional devices should all use __virtioXX types (and __leXX for
fields not present in the legacy devices).
Modern ones should use __leXX.
_uXX type would be a bug.
Let's prevent that.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Min compiler version has been raised, so that's ok now.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Use vars of the correct type instead of casting.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

VDPA sim accesses config space as native endian - this is
wrong since it's a modern device and actually uses LE.

It only supports modern guests so we could punt and
just force LE, but let's use the full virtio APIs since people
tend to copy/paste code, and this is not data path anyway.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

We normally expect vdpa to use the modern interface.
However for consistency, let's use same APIs as vhost
for legacy guests.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

For new helpers handling legacy features to be effective,
vhost needs to invoke them. Tie them in.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Some legacy guests just assume features are 0 after reset.
We detect that config space is accessed before features are
set and set features to 0 automatically.
Note: some legacy guests might not even access config space, if this is
reported in the field we might need to catch a kick to handle these.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

mlxbf-tmfifo accesses config space using native types -
which works for it since the legacy virtio native types.

This will break if it ever needs to support modern virtio,
so with new tags previously introduced for virtio net config,
sparse now warns for this in drivers.

Since this is a legacy only device, fix it up using
virtio_legacy_is_little_endian for now.

No functional changes.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Transitional devices should all use __virtioXX types (and __leXX for
fields not present in legacy devices).
Modern ones should use __leXX.
_uXX type would be a bug.
Let's prevent that.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since this is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Since this is a modern-only device,
tag config space fields as having little endian-ness.

TODO: check other uses of __virtioXX types in this header,
should probably be __leXX.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since this is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since this is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since gpu is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since fs is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Since crypto is a modern-only device,
tag config space fields as having little endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Tag config space fields as having little endian-ness.
Note that balloon is special: LE even when using
the legacy interface.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Tag config space fields as having virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Currently all config space fields are of the type __uXX.
This confuses people and some drivers (notably vdpa)
access them using CPU endian-ness - which only
works well for legacy or LE platforms.

Update virtio_cread/virtio_cwrite macros to allow __virtioXX
and __leXX field types. Follow-up patches will convert
config space to use these types.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>

virtio_store_mb was built with split ring in mind so it accepts
__virtio16 arguments. Packed ring uses __le16 values, so sparse
complains.  It's just a store with some barriers so let's convert it to
a macro, we don't loose too much type safety by doing that.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>

balloon uses virtio32_to_cpu instead of cpu_to_virtio32
to convert a native endian number to virtio.
No practical difference but makes sparse warn.
Fix it up.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Now that the corresponding feature bit has been renamed,
rename the quirk too - it's about special ways to
do DMA, not necessarily about the IOMMU.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>