Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

[Jason Wang <jasowang@redhat.com>]

在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
> On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
>> This patch switch to read virtqueue size from the capability instead
>> of depending on the hardcoded value. This allows the per virtqueue
>> size could be advertised.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
> So let's add an ioctl for this? It's really a bug we don't..


As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM 
actually. Instead it checks the result VHOST_VDPA_SET_VRING_NUM.

So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all 
the virtqueues.

If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it 
will have a user or not.

Thanks


>
>> ---
>>   drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> index 2926641fb586..198f7076e4d9 100644
>> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
>> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
>> @@ -18,7 +18,6 @@
>>   #include <linux/virtio_pci.h>
>>   #include <linux/virtio_pci_modern.h>
>>   
>> -#define VP_VDPA_QUEUE_MAX 256
>>   #define VP_VDPA_DRIVER_NAME "vp_vdpa"
>>   #define VP_VDPA_NAME_SIZE 256
>>   
>> @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>>   
>>   static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
>>   {
>> -	return VP_VDPA_QUEUE_MAX;
>> +	struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
>> +	struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
>> +
>> +	return vp_modern_get_queue_size(mdev, qid);
>>   }
>>   
>>   static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
>> -- 
>> 2.25.1