From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42728) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ctmib-00047c-HC for qemu-devel@nongnu.org; Thu, 30 Mar 2017 22:55:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ctmiY-0000DG-EX for qemu-devel@nongnu.org; Thu, 30 Mar 2017 22:55:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52672) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ctmiY-0000CZ-8k for qemu-devel@nongnu.org; Thu, 30 Mar 2017 22:55:14 -0400 Date: Thu, 30 Mar 2017 20:55:11 -0600 From: Alex Williamson Message-ID: <20170330205511.28be6306@t450s.home> In-Reply-To: <8082FF9BCB2B054996454E47167FF4EC1C4930B3@SHSMSX104.ccr.corp.intel.com> References: <1490869641-29873-1-git-send-email-xiong.y.zhang@intel.com> <20170330090148.16048141@t450s.home> <8082FF9BCB2B054996454E47167FF4EC1C4930B3@SHSMSX104.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Zhang, Xiong Y" Cc: "qemu-devel@nongnu.org" On Fri, 31 Mar 2017 02:27:11 +0000 "Zhang, Xiong Y" wrote: > > On Thu, 30 Mar 2017 18:27:21 +0800 > > Xiong Zhang wrote: > > > > > This reverts commit c2b2e158cc7b1cb431bd6039824ec13c3184a775. > > > > > > The original patch intend to prevent linux i915 driver from using > > > stolen meory. But this patch breaks windows IGD driver loading on > > > Gen9+, as IGD HW will use stolen memory on Gen9+, once windows IGD > > > driver see zero size stolen memory, it will unload. > > > Meanwhile stolen memory will be disabled in 915 when i915 run as > > > a guest. > > > > Does this mean that legacy mode IGD assignment is not going to work > > on Gen9+ with Windows? Will it continue to work with Gen8-? > [Zhang, Xiong Y] I try to use the following qemu command to enable legacy mode on SKyLake, but It seems the entry point of wins IGD driver isn't called(I couldn't confirm this as I don't have the source code, but I didn't see any IGD driver info from windbg while I could see many info in upt mode), so driver doesn't bind to IGD after win 8.1 boot up. > #qemu-system-x86_64 -M pc -enable-kvm -smp 2 -m 2G -vga none -nographic -cpu host -hda "$IMAGE" -device vfio-pci,host=00:02.0,x-vga=true,id=hostdev0,bus=pci.0,addr=0x2 > Is this the right method to enable legacy mode ? Yeah, that should do it. x-vga should not be necessary, but shouldn't hurt IIRC. Any dmesg errors regarding the ROM? I think we have trouble with the ROM if the host is booted in UEFI mode. > > > Please clarify Gen9+, is this Kaby Lake? > [Zhang, Xiong Y] Gen 9+ is SkyLake and later. Ok, then I cannot test since I only have access to BDW. We do have users that might start complaining if this is a new change in the Windows driver for SKL+. > > I assume this patch is intended for QEMU 2.9, it's helpful to make that > > explicit during the rc freeze. Thanks, > [Zhang, Xiong Y] Yes, as the original patch has entered into Qemu 2.9 rc1. So this reverted patch should be entered into the later 2.9 rc. > Sorry for the troubles. Ok, no problem. Thanks, Alex