Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa

[Jason Wang <jasowang@redhat.com>]

在 2022/1/5 下午2:40, Longpeng (Mike, Cloud Infrastructure Service Product 
Dept.) 写道:
>
>> -----Original Message-----
>> From: Jason Wang [mailto:jasowang@redhat.com]
>> Sent: Wednesday, January 5, 2022 12:36 PM
>> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
>> <longpeng2@huawei.com>
>> Cc: Stefan Hajnoczi <stefanha@redhat.com>; mst <mst@redhat.com>; Stefano
>> Garzarella <sgarzare@redhat.com>; Cornelia Huck <cohuck@redhat.com>; pbonzini
>> <pbonzini@redhat.com>; Gonglei (Arei) <arei.gonglei@huawei.com>; Yechuan
>> <yechuan@huawei.com>; Huangzhichao <huangzhichao@huawei.com>; qemu-devel
>> <qemu-devel@nongnu.org>
>> Subject: Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa
>>
>> On Wed, Jan 5, 2022 at 8:59 AM Longpeng(Mike) <longpeng2@huawei.com> wrote:
>>> From: Longpeng <longpeng2@huawei.com>
>>>
>>> To support generic vdpa deivce, we need add the following ioctls:
>>> - GET_VECTORS_NUM: the count of vectors that supported
>> Does this mean MSI vectors? If yes, it looks like a layer violation:
>> vhost is transport independent.  And it reveals device implementation
>> details which block (cross vendor) migration.
>>
> Can we set the VirtIOPCIProxy.nvectors to "the count of virtqueues + 1 (config)" ?


That should work.

Thanks


>
>> Thanks
>>
>>> - GET_CONFIG_SIZE: the size of the virtio config space
>>> - GET_VQS_NUM: the count of virtqueues that exported
>>>
>>> Signed-off-by: Longpeng <longpeng2@huawei.com>
>>> ---
>>>   linux-headers/linux/vhost.h | 10 ++++++++++
>>>   1 file changed, 10 insertions(+)
>>>
>>> diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h
>>> index c998860d7b..c5edd75d15 100644
>>> --- a/linux-headers/linux/vhost.h
>>> +++ b/linux-headers/linux/vhost.h
>>> @@ -150,4 +150,14 @@
>>>   /* Get the valid iova range */
>>>   #define VHOST_VDPA_GET_IOVA_RANGE      _IOR(VHOST_VIRTIO, 0x78, \
>>>                                               struct vhost_vdpa_iova_range)
>>> +
>>> +/* Get the number of vectors */
>>> +#define VHOST_VDPA_GET_VECTORS_NUM     _IOR(VHOST_VIRTIO, 0x79, int)
>>> +
>>> +/* Get the virtio config size */
>>> +#define VHOST_VDPA_GET_CONFIG_SIZE     _IOR(VHOST_VIRTIO, 0x80, int)
>>> +
>>> +/* Get the number of virtqueues */
>>> +#define VHOST_VDPA_GET_VQS_NUM         _IOR(VHOST_VIRTIO, 0x81, int)
>>> +
>>>   #endif
>>> --
>>> 2.23.0
>>>