From: "Zhang, Xiong Y" <xiong.y.zhang@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Zhang, Xiong Y" <xiong.y.zhang@intel.com>
Subject: Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO"
Date: Fri, 31 Mar 2017 02:27:11 +0000 [thread overview]
Message-ID: <8082FF9BCB2B054996454E47167FF4EC1C4930B3@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <20170330090148.16048141@t450s.home>
> On Thu, 30 Mar 2017 18:27:21 +0800
> Xiong Zhang <xiong.y.zhang@intel.com> 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 ?
> Please clarify Gen9+, is this Kaby Lake?
[Zhang, Xiong Y] Gen 9+ is SkyLake and later.
> 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.
next prev parent reply other threads:[~2017-03-31 2:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-30 10:27 [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO" Xiong Zhang
2017-03-30 15:01 ` Alex Williamson
2017-03-31 2:27 ` Zhang, Xiong Y [this message]
2017-03-31 2:55 ` Alex Williamson
2017-03-31 7:07 ` Zhang, Xiong Y
2017-03-31 17:03 ` Igor Mammedov
2017-03-31 17:27 ` Alex Williamson
2017-04-01 2:35 ` Zhang, Xiong Y
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