From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28693C352AA for ; Tue, 1 Oct 2019 18:45:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0261D215EA for ; Tue, 1 Oct 2019 18:45:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569955532; bh=tSA0eH9++rEulu7t4v7lBqNfCOSP45VX2fYHTJajmIw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=PpKk41X5ockMffZApoe/3qpua6eUtGFrx/CoFn8vqdVdmIlHgFLYCe9qdyPTJpeq2 o0ASw4yjn2u6s18pC/eRp+6EYuUNadQ39UjHn3esa2W/XyyXxjcpHe2UNRHvu9MUbQ bNvTbtR0d20quVPau1ufMYNy8GMOLv5bImpUHbLY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726100AbfJASpb (ORCPT ); Tue, 1 Oct 2019 14:45:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:36000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725851AbfJASp2 (ORCPT ); Tue, 1 Oct 2019 14:45:28 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1DD95215EA; Tue, 1 Oct 2019 18:45:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569955527; bh=tSA0eH9++rEulu7t4v7lBqNfCOSP45VX2fYHTJajmIw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hGwXl5KenUFK6V19PoWZFBUaizhy7wGsLSmuwo71F64a03cLn+s42VVQQxB3oM4VA xvWwn8ePcDfEv9LhI3Aghg+dlRq8CXruUwcqoTicuXQtSBTVo5AVacMZkg9tDQWCM2 91TZgYTkyx2usfmibcp0aptevWtTjOCNyUA2LN48= Date: Tue, 1 Oct 2019 14:45:26 -0400 From: Sasha Levin To: Wei Hu Cc: Michael Kelley , "rdunlap@infradead.org" , "shc_work@mail.ru" , "gregkh@linuxfoundation.org" , "lee.jones@linaro.org" , "alexandre.belloni@bootlin.com" , "baijiaju1990@gmail.com" , "fthain@telegraphics.com.au" , "info@metux.net" , "linux-hyperv@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-fbdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Stephen Hemminger , Haiyang Zhang , KY Srinivasan , Dexuan Cui Subject: Re: [PATCH v5] video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver Message-ID: <20191001184526.GE8171@sasha-vm> References: <20190913060209.3604-1-weh@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190913060209.3604-1-weh@microsoft.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org 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 What tree is this based on? I can't get it to apply. -- Thanks, Sasha