Messages in this thread | | | Date | Tue, 1 Oct 2019 14:45:26 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH v5] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver |
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On Fri, Sep 13, 2019 at 06:02:55AM +0000, Wei Hu wrote: >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@microsoft.com>
What tree is this based on? I can't get it to apply.
-- Thanks, Sasha
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