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Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memor
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO" |
Date: |
Thu, 30 Mar 2017 20:55:11 -0600 |
On Fri, 31 Mar 2017 02:27:11 +0000
"Zhang, Xiong Y" <address@hidden> wrote:
> > On Thu, 30 Mar 2017 18:27:21 +0800
> > Xiong Zhang <address@hidden> 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
- [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Xiong Zhang, 2017/03/30
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Alex Williamson, 2017/03/30
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Zhang, Xiong Y, 2017/03/30
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO",
Alex Williamson <=
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Zhang, Xiong Y, 2017/03/31
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Igor Mammedov, 2017/03/31
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Alex Williamson, 2017/03/31
- Re: [Qemu-devel] [PATCH] Revert "vfio/pci-quirks.c: Disable stolen memory for igd VFIO", Zhang, Xiong Y, 2017/03/31