Messages in this thread | | | From | Cornelia Huck <> | Subject | Re: [PATCH V2 4/5] virtio-pci: implement synchronize_vqs() | Date | Tue, 12 Apr 2022 18:48:47 +0200 |
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On Tue, Apr 12 2022, Halil Pasic <pasic@linux.ibm.com> wrote:
> On Mon, 11 Apr 2022 16:27:41 +0200 > Cornelia Huck <cohuck@redhat.com> wrote:
>> My main concern is that we would need to synchronize against a single >> interrupt that covers all kinds of I/O interrupts, not just a single >> device... >> > > Could we synchronize on struct airq_info's lock member? If we were > to grab all of these that might be involved...
Hm, that could possibly narrow the sync down to a subset, which seems better. For devices still using classic interrupts, per-device sync would be easy.
> > AFAIU for the synchronize implementation we need a lock or a set of locks > that contain all the possible vring_interrupt() calls with the queuues > that belong to the given device as a critical section. That way, one > has the acquire's and release's in place so that the vrign_interrupt() > either guaranteed to finish before the change of driver_ready is > guaranteed to be complete, or it is guaranteed to see the change. > > In any case, I guess we should first get clear on the first part. I.e. > when do we want to allow host->guest notifications.
Also, whether we just care about vring interrupts, or general device interrupts (not sure if a config change interrupt may also trigger things we do not want to trigger?)
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