Re: [RFC 7/11] virtio_pci: new, capability-aware driver.
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On Sun, 18 Dec 2011 12:18:32 +0200, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > On Fri, Dec 16, 2011 at 12:20:08PM +1030, Rusty Russell wrote: > > Perhaps a new feature VIRTIO_F_UNSTABLE? Which (unlike other features) > > appears and vanishes around config writes by either side? Kind of a > > hack though... > > Not sure how this can work in such a setup: when would guest > check this bit to avoid races? > A separate registers also seems nicer than a flag. > > Some other possible design choices: > - a flag to signal config accesses in progress by guest > host would need to buffer changes and apply them in one go > when flag is cleared > - a register to make host get/set config in guest memory > - use a control vq for all devices - seqlock-style generation count register(s)? Has the advantage of being a noop if things never change. - continue to ignore it ;) And yes, it's a more general problem than virtio_pci... Cheers, Rusty. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization