Re: [PATHC v6] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver

[Sasha Levin]

On Wed, Oct 02, 2019 at 08:09:41AM +0000, Dexuan Cui wrote:
> > -----Original Message-----
> > From: Sasha Levin <sashal@xxxxxxxxxx>
> > Sent: Tuesday, October 1, 2019 11:48 AM
> >
> > On Fri, Sep 20, 2019 at 05:26:34PM +0000, Michael Kelley wrote:
> > >From: Michael Kelley <mikelley@xxxxxxxxxxxxx>  Sent: Wednesday,
> > September 18, 2019 2:48 PM
> > >> >
> > >> > Without deferred IO support, hyperv_fb driver informs the host to refresh
> > >> > the entire guest frame buffer at fixed rate, e.g. at 20Hz, no matter there
> > >> > is screen update or not. This patch supports deferred IO for screens in
> > >> > graphics mode and also enables the frame buffer on-demand refresh. The
> > >> > highest refresh rate is still set at 20Hz.
> > >> >
> > >> > Currently Hyper-V only takes a physical address from guest as the starting
> > >> > address of frame buffer. This implies the guest must allocate contiguous
> > >> > physical memory for frame buffer. In addition, Hyper-V Gen 2 VMs only
> > >> > accept address from MMIO region as frame buffer address. Due to these
> > >> > limitations on Hyper-V host, we keep a shadow copy of frame buffer
> > >> > in the guest. This means one more copy of the dirty rectangle inside
> > >> > guest when doing the on-demand refresh. This can be optimized in the
> > >> > future with help from host. For now the host performance gain from
> > deferred
> > >> > IO outweighs the shadow copy impact in the guest.
> > >> >
> > >> > Signed-off-by: Wei Hu <weh@xxxxxxxxxxxxx>
> > >
> > >Sasha -- this patch and one other from Wei Hu for the Hyper-V frame buffer
> > >driver should be ready.  Both patches affect only the Hyper-V frame buffer
> > >driver so can go through the Hyper-V tree.  Can you pick these up?  Thx.
> >
> > I can't get this to apply anywhere, what tree is it based on?
> >
> > --
> > Thanks,
> > Sasha
>
> Hi Sasha,
> Today's hyperv/linux.git's hyperv-next branch's top commit is
>    48b72a2697d5 ("hv_netvsc: Add the support of hibernation").
>
> Please pick up two patches from Wei Hu:
> #1: [PATCH v4] video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V host
> #2: [PATHC v6] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver

Ah, I guess I was missing the first one. I've queued both for
hyperv-next, thanks!

--
Thanks,
Sasha