Re: [PATCH v2] vdpa: Fix endian bugs in shadow virtqueue

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 13/2/25 07:43, Eugenio Perez Martin wrote:
> On Wed, Feb 12, 2025 at 7:11 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
>>
>> On 12/2/25 17:49, Konstantin Shkolnyy wrote:
>>> VDPA didn't work on a big-endian machine due to missing/incorrect
>>> CPU<->LE data format conversions.
>>>
>>> Signed-off-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
>>> ---
>>> Changes in v2: Change desc_next[] from LE format to "CPU".
>>>
>>>    hw/virtio/vhost-shadow-virtqueue.c | 18 ++++++++++--------
>>>    1 file changed, 10 insertions(+), 8 deletions(-)
>>
>>
>>> @@ -228,10 +228,12 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
>>>        smp_mb();
>>>
>>>        if (virtio_vdev_has_feature(svq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
>>> -        uint16_t avail_event = *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]);
>>> +        uint16_t avail_event = le16_to_cpu(
>>> +                *(uint16_t *)(&svq->vring.used->ring[svq->vring.num]));
>>
>> Nitpicking, sometimes using the ld/st API is cleaner (here lduw_le_p).
>>
> 
> I'm not sure if it is right in SVQ, as it is not accessing guest
> memory but QEMU memory that has been mapped to a device. But if you
> think it is still a valid use case for ld* and st* family I'd be
> totally ok with that usage.

No need to change, better use a consistent API over the file.

Regards,

Phil.