virtio — archive

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

From: Cornelia Huck <[email protected]>
To: [email protected]
Date: Fri, 25 Nov 2022 12:10:00 -0000

On Fri, Nov 25 2022, "Michael S. Tsirkin" <[email protected]> wrote: > 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. Ok, so not completely useless.