virtio — archive

RE: [virtio] RE: [virtio-comment] proposal: use admin command (and aq) of the device to query config space

From: Parav Pandit <[email protected]>
To: [email protected]
Date: Wed, 02 Aug 2023 11:56:00 -0000

> From: Michael S. Tsirkin <[email protected]> > Sent: Wednesday, August 2, 2023 5:21 PM > > There's one thing to say about putting everything in one place, and that is that > one can then find everything in one place. When a device grows incrementally and each functionality also, grouping it per functionality gives better pace to keep things self-contained. Think how messy a set command would be if all 3 functionality in one set command. > For example, at the moment we actually do have a problem with cvq, and the > problem is that it sets internal device state that is not observable (unlike original > pre-1.0 config space which was writeable). > Which part is not observable? > > By the way there's a pci express ECN for relaxed ordering or something like this. > I am yet to look at it, I wonder whether it can be used to avoid the issues we > have with MMIO in a way that is easier to use than DMA. Waiting to deliver new features on new PCI standard will drastically slow down virtio. I don't think its good idea, but I would like to know about such ECN, if there is one.