Re: [virtio-dev] Device-to-driver notification management for hardware implementations

[Stefan Hajnoczi <stefanha@redhat.com>]

On Wed, Sep 12, 2018 at 05:41:07PM +0100, David Riddoch wrote:
> The VIRTIO_F_NOTIFICATION_DATA feature helps hardware implementations by
> telling them directly how many descriptors are available in the ring, saving
> speculative reads.  There is a related issue with interrupts: As things
> stand, after writing 'used' descriptors into the ring (packed or split) the
> device has to read the event idx to determine whether a device-to-driver
> notification (interrupt) is needed.
> 
> It would be very helpful to a hardware implementation if the event idx could
> be written directly to the device.  Has anyone proposed an extension to
> address this already?  (I have some thoughts on how to do this if we don't
> have a proposal yet).

Hi David,
Has there been any further discussion on this topic?  It seems like a
useful feature to have in VIRTIO.

Stefan

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