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
