From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Date: Tue, 01 Oct 2019 18:48:28 +0000 Subject: Re: [PATHC v6] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver Message-Id: <20191001184828.GF8171@sasha-vm> List-Id: References: <20190918060227.6834-1-weh@microsoft.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Michael Kelley Cc: "info@metux.net" , "alexandre.belloni@bootlin.com" , Wei Hu , "shc_work@mail.ru" , "gregkh@linuxfoundation.org" , Haiyang Zhang , "rdunlap@infradead.org" , Dexuan Cui , "linux-hyperv@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "baijiaju1990@gmail.com" , "linux-fbdev@vger.kernel.org" , Stephen Hemminger , KY Srinivasan , "lee.jones@linaro.org" On Fri, Sep 20, 2019 at 05:26:34PM +0000, Michael Kelley wrote: >From: Michael Kelley 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 > >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