[v3] virtio: features,fixes

[PULL v3 74/85] virtio: remove virtio_tswap16s() call in vring_packed_event_read()

Michael S. Tsirkin posted 85 patches 2 months, 2 weeks ago

Diff against v1 v1 v2 v2 v3
Download mbox

Maintainers: David Hildenbrand <david@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Raphael Norwitz <raphael@enfabrica.net>, "Michael S. Tsirkin" <mst@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Shannon Zhao <shannon.zhaosl@gmail.com>, Ani Sinha <anisinha@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Fan Ni <fan.ni@samsung.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Sergio Lopez <slp@redhat.com>, Akihiko Odaki <akihiko.odaki@daynix.com>, Sriram Yagnaraman <sriram.yagnaraman@ericsson.com>, Jason Wang <jasowang@redhat.com>, Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>, Jesper Devantier <foss@defmacro.it>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, Harsh Prateek Bora <harshpb@linux.ibm.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Fam Zheng <fam@euphon.net>, "Alex Bennée" <alex.bennee@linaro.org>, Stefan Hajnoczi <stefanha@redhat.com>, Eric Auger <eric.auger@redhat.com>, Stefano Stabellini <sstabellini@kernel.org>, Anthony PERARD <anthony@xenproject.org>, Paul Durrant <paul@xen.org>, Cornelia Huck <cohuck@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>, David Woodhouse <dwmw2@infradead.org>, Laurent Vivier <lvivier@redhat.com>, Coiby Xu <Coiby.Xu@gmail.com>

Expand all Fold all

[PULL v3 74/85] virtio: remove virtio_tswap16s() call in vring_packed_event_read()

Posted by Michael S. Tsirkin 2 months, 2 weeks ago

From: Stefano Garzarella <sgarzare@redhat.com>

Commit d152cdd6f6 ("virtio: use virtio accessor to access packed event")
switched using of address_space_read_cached() to virito_lduw_phys_cached()
to access packed descriptor event.

When we used address_space_read_cached(), we needed to call
virtio_tswap16s() to handle the endianess of the field, but
virito_lduw_phys_cached() already handles it internally, so we no longer
need to call virtio_tswap16s() (as the commit had done for `off_wrap`,
but forgot for `flags`).

Fixes: d152cdd6f6 ("virtio: use virtio accessor to access packed event")
Cc: jasowang@redhat.com
Cc: qemu-stable@nongnu.org
Reported-by: Xoykie <xoykie@gmail.com>
Link: https://lore.kernel.org/qemu-devel/CAFU8RB_pjr77zMLsM0Unf9xPNxfr_--Tjr49F_eX32ZBc5o2zQ@mail.gmail.com
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20240701075208.19634-1-sgarzare@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 3678ec2f88..583a224163 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -323,7 +323,6 @@ static void vring_packed_event_read(VirtIODevice *vdev,
     /* Make sure flags is seen before off_wrap */
     smp_rmb();
     e->off_wrap = virtio_lduw_phys_cached(vdev, cache, off_off);
-    virtio_tswap16s(vdev, &e->flags);
 }
 
 static void vring_packed_off_wrap_write(VirtIODevice *vdev,
-- 
MST