Re: [PATCHv7 00/16] Linux: FIFO-based event channel ABI

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 10/18/2013 10:23 AM, David Vrabel wrote:
> This is the complete Linux guest-side implementation of the FIFO-based
> event channel ABI described in this design document:

With one more comment for 06/16,

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

>
>    http://xenbits.xen.org/people/dvrabel/event-channels-F.pdf
>
> The Xen implementation is now available in xen-unstable.
>
> Note that __startup_pirq() was never ideal as failure when binding a
> PIRQ to an event channel cannot be propagated to the calling driver
> since the irq_startup callback cannot return an error.  This series
> adds another (very unlikely) failure point to __startup_pirq().
>
> I have a half-bakedpatch series to refactor when PIRQs are setup and
> torn down but this won't be ready for a while and I do not think this
> is a prerequisite for applying the FIFO-based ABI series.
>
> Patch 1 is a obvious refactoring of common code.
>
> Patch 2-6 prepare for supporting multiple ABIs.
>
> Patch 7 adds the low-level evtchn_ops hooks.
>
> Patch 8-9 add an additional hook for ABI-specific per-port setup
> (used for expanding the event array as more event are bound).
>
> Patch 10 allows many more event channels to be supported by altering
> how the event channel to irq map is allocated.  Note that other
> factors limit the number of supported IRQs (IRQs is 8192 + 64 *
> NR_CPUS).
>
> Patch 11 is some trival refactoring.
>
> Patch 12 removes a limit on the number of event channels supported by
> the xen-evtchn driver.
>
> Patch 13 adds the hypervisor ABI.
>
> Patches 14-15 Set the priority of VIRQ_TIMER events to the highest.
>
> Patch 16 adds the FIFO-based ABI implementation.
>
> Changes in v7:
>
> - Add xen.fifo_events command line option (defaults to true).
> - Use xen_evtchn_nr_channels() in xen_evtchn driver.
> - Drop unnecessary test in evtchn_fifo_unmask()
> - Refactor irq_info setup/cleanup a bit.
>
> Changes in v6:
>
> - nlevel -> 2l to match naming in Xen.
>
> Changes in v5 (v4 not posted):
>
> - Set priority of VIRQ_TIMER.
> - Remove NR_EVENT_CHANNELS limit from xen-evtchn driver.
> - Licence drivers/xen/events/fifo.c under a dual MIT/GPLv2.
>
> Changes in v3:
>
> - Support suspend/resume by reinitializing the control blocks on resume.
> - Only init control block if one does not exist (should fix CPU
>    hotplug).
>