virtio — archive

[PATCH v9 00/10] Introduce device group and device management

From: Michael S. Tsirkin <[email protected]>
To: [email protected]
Date: Fri, 25 Nov 2022 11:56:00 -0000

On Fri, Nov 25, 2022 at 12:42:23PM +0100, Cornelia Huck wrote: > On Fri, Nov 25 2022, Jason Wang <[email protected]> wrote: > > > ? 2022/11/24 16:36, Michael S. Tsirkin ??: > >> On Thu, Nov 24, 2022 at 02:51:21PM +0800, Jason Wang wrote: > >>> On Thu, Nov 24, 2022 at 5:08 AM Michael S. Tsirkin <[email protected]> wrote: > >>>> +The device MUST NOT fail a command solely because the buffers > >>>> +provided are shorter or longer than described in this > >>>> +specification. > >>> I may miss something but how can it work if the buffer is shorter? > >> driver does not care what's there. > >> > >> this is mostly for forward compatibility - we'll add more fields and > >> I don't want to explain separately that old drivers post > >> short buffers with less fields. > > > > > > For example: > > > > The patch said: > > > > struct virtio_admin_cmd_list { > > /* Indicates which of the below fields were returned > > le32 device_admin_cmds[]; > > }; > > > > Does it mean the query can still succeed even if there's no space for > > virtio_admin_cmd_list in the writable buffer? > > Can we pick an absolute minimum length? All drivers need to be able to > at least accommodate this one. Or is it ok for the driver to send a > completely useless query that doesn't get any data back? I think it might be a way to check that a group exists. -- MST