Re: [Query] [GUEST PAGE HINTING] How to handle virtqueue_kick from the guest in QEMU

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Aug 17, 2017 at 06:53:31PM +0200, Paolo Bonzini wrote:
> On 11/08/2017 23:00, Nitesh Narayan Lal wrote:
> > One way to go about
> > this is to have my own function pointer pointing a to a function
> > qemu_page_hinting() in virtio-balloon.c under QEMU. Now the part where I
> > am not sure is how exactly I will ensure that when virtqueue_kick
> > arrives in QEMU this function is invoked. (I am planning to use the same
> > deflate_vq for my use-case).
> 
> You can use a separate virtq as Michael mentioned.
> 
> Another possibility is to extend virtio-balloon to support 64-bit values
> in the virtqueues.  Then when shifting PFNs right you have bits 52-63
> free, and you can put flags in there (e.g. bit 52=0 means deflate, bit
> 52=1 means page hint).
>
> Of course, if your action is going to be MADV_DONTNEED, you don't need
> to do anything special.
> 
> Paolo

Forgot to say: when you discuss virtio host/guest interface changes,
please copy virtio-dev@lists.oasis-open.org. (Subscriber only, sorry
about that).

-- 
MST