virtio — archive

[PATCH v10 00/10] Introduce device group and device management

From: David Edmondson <[email protected]>
To: [email protected]
Date: Wed, 08 Mar 2023 12:59:00 -0000

"Michael S. Tsirkin" <[email protected]> writes: > On Tue, Mar 07, 2023 at 11:04:33AM +0000, David Edmondson wrote: >> "Michael S. Tsirkin" <[email protected]> writes: >> > +The driver MAY block use of VIRTIO_ADMIN_CMD_LIST_QUERY and >> > +VIRTIO_ADMIN_CMD_LIST_USE by issuing VIRTIO_ADMIN_CMD_LIST_USE >> > +with respective bits cleared in \field{command_specific_data}. >> >> This runs contrary to the assertion "The list of supported commands MUST >> NOT shrink", given that a driver is told to assume that >> VIRTIO_ADMIN_CMD_LIST_QUERY and VIRTIO_ADMIN_CMD_LIST_USE are the only >> commands initially available. > > Commands are still available just disabled, the meaning of > "MUST NOT shrink" is clarified by the following: > > > > +after reporting a given command as supported through > > > +VIRTIO_ADMIN_CMD_LIST_QUERY the device MUST NOT later report it > > > +as unsupported. > I will stick an "i.e." there to make it hopefully clearer. This puzzles me. I can see the point of blocking LIST_USE, but not of blocking LIST_QUERY. What's the purpose of this? -- Time is waiting to explain, why refuse?