Re: [Qemu-devel] [RFC PATCH v5 0/7] vfio IGD assignment

[nicolas prochazka <prochazka.nicolas@gmail.com>]

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hello again,
I'm compiling linux kernel 4.6rc5
i'm compiling your qemu and seabios git

then , I unbind my vga card :
echo "0000:00:02.0" > /sys/bus/pci/devices/0000\:00\:02.0/driver/unbind

and start qemu with this command line ( from ssh )

 /usr/bin/qemu-kvm -name win -S -machine pc-i440fx-2.6,accel=kvm,usb=off
-cpu host,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1fff -m 14257
-mem-prealloc -mem-path /dev/hugepages/libvirt/qemu -realtime mlock=off
-smp 2,sockets=1,cores=2,threads=1 -uuid
ab829652-e53a-32bf-9a18-6722c7e7f785  -global PIIX4_PM.disable_s3=1 -global
PIIX4_PM.disable_s4=1 -boot strict=on -device
piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -drive
file=nbd:unix:/tmp/win.ctl,if=none,id=drive-ide0-0-0,format=raw -device
ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -drive
file=nbd:unix:/tmp/swap.ctl,if=none,id=drive-ide0-0-1,format=raw -device
ide-hd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -device
vfio-pci,host=0000:00:02.0,bus=pci.0,addr=02.0 -vga none

*qemu-system-x86_64: -device
vfio-pci,host=0000:00:02.0,bus=pci.0,addr=02.0: PCI: slot 2 function 0 not
available for vfio-pci, in use by e1000*

what is wrong ?
regards,
Nicolas

lspci shows us :

00:00.0 Host bridge [0600]: Intel Corporation Sky Lake Host Bridge/DRAM
Registers [8086:1904] (rev 09)
00:02.0 VGA compatible controller [0300]: Intel Corporation Sky Lake
Integrated Graphics [8086:1926] (rev 0a)
00:14.0 USB controller [0c03]: Intel Corporation Device [8086:9d2f] (rev 21)
00:14.2 Signal processing controller [1180]: Intel Corporation Device
[8086:9d31] (rev 21)
00:16.0 Communication controller [0780]: Intel Corporation Device
[8086:9d3a] (rev 21)
00:17.0 SATA controller [0106]: Intel Corporation Device [8086:9d03] (rev
21)
00:1c.0 PCI bridge [0604]: Intel Corporation Device [8086:9d14] (rev f1)
00:1d.0 PCI bridge [0604]: Intel Corporation Device [8086:9d18] (rev f1)
00:1e.0 Signal processing controller [1180]: Intel Corporation Device
[8086:9d27] (rev 21)
00:1e.6 SD Host controller [0805]: Intel Corporation Device [8086:9d2d]
(rev 21)
00:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:9d48] (rev 21)
00:1f.2 Memory controller [0580]: Intel Corporation Device [8086:9d21] (rev
21)
00:1f.3 Audio device [0403]: Intel Corporation Device [8086:9d70] (rev 21)
00:1f.4 SMBus [0c05]: Intel Corporation Device [8086:9d23] (rev 21)
00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection
I219-V [8086:1570] (rev 21)
01:00.0 Network controller [0280]: Intel Corporation Wireless 8260
[8086:24f3] (rev 3a)
02:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd
Device [144d:a802] (rev 01)


2016-04-21 17:56 GMT+02:00 Alex Williamson <alex.williamson@redhat.com>:

> This series enables "legacy mode" Intel graphics device assignment on
> SandyBridge and newer CPUs when coupled with a v4.6 Linux host kernel
> and updated SeaBIOS[1].  Legacy mode assignment in this context means
> that we modify the VM to supply the features required for IGD, such as
> an OpRegion, stolen memory, host bridge and ISA bridge, and VGA, as
> opposed to Intel's Universal Pass-Through (UPT) mode where IGD can be
> assigned as if it were a discrete PCI device, with no additional
> modifications of the VM.  The benefit of legacy mode is that we can
> support older hardware, primary graphics mode in the VM, and physical
> display outputs.
>
> Additionally this series adds an new x-igd-opregion=on option which is
> intended to be coupled with UPT mode to enable physically connected
> displays.  This has the same SeaBIOS requirement as legacy mode.
>
> What's new in v5?  Support for generation 8 and newer IGD, such as
> Broadwell and Skylake.  These GPUs support 64bit PTEs, changing the
> GTT sizing and layout.  We also now invalidate the GTT which avoids
> the majority of DMAR faults when assigning these devices.  OpRegion
> support is no longer automatic, except in legacy mode, since it can
> interfere with headless UPT setups.
>
> Legacy mode will only be enabled when IGD is configured at VM address
> 00:02.0, a ROM is present, VGA is available, and the host kernel
> supports vfio device specific regions providing the OpRegion, host
> config space, and ISA/LPC bridge config access.
>
> What's left to do?  Obviously this is post-2.6 material, otherwise
> the remaining blocker is SeaBIOS support.  SeaBIOS would prefer an
> interface that allows reserved memory regions to be assigned and
> populated generically and the base address returned to QEMU without
> SeaBIOS needing device specific code.
>
> What about OVMF/Q35?  The VGA ROM is a critical component of IGD
> legacy mode, but IME the ROM is only a legacy ROM without UEFI
> support.  Therefore I expect it would only be compatible with OVMF
> when run with a CSM, which is not our default.  OpRegion support is
> certainly something we can investigate with OVMF for UPT+OpRegion
> mode on an OVMF VM.  Q35 is unfortunately incompatible with legacy
> mode because in most configurations it already places an LPC/ISA
> bridge at address 00:1f.0 in the VM.  We can't very well modify that
> PCI device to report itself as the host LPC bridge since the feature
> set of the Q35 bridge may be different.  Again, UPT mode is the
> solution here.  Legacy mode will not fail due to a Q35 machine type,
> but will fail if address 00:1f.0 is populated with anything other
> than a vfio-pci-igd-lpc-bridge device.
>
> Note to laptop users, I generally expect that screen dimming and lid
> switches are implemented in ACPI, outside of anything supported here.
> Laptop displays are also more fickle with generic drivers and may not
> work without native device drivers (ie. the windows basic driver may
> not drive the display during an install).
>
> Please test and review.  Thanks,
>
> Alex
>
> [1] http://patchwork.ozlabs.org/patch/583731
> ---
>
> Alex Williamson (7):
>       vfio: Enable sparse mmap capability
>       vfio: Create device specific region info helper
>       vfio/pci: Fix return of vfio_populate_vga()
>       vfio/pci: Consolidate VGA setup
>       vfio/pci: Setup BAR quirks after capabilities probing
>       vfio/pci: Intel graphics legacy mode assignment
>       vfio/pci: Add a separate option for IGD OpRegion support
>
>
>  hw/vfio/common.c              |  103 +++++++
>  hw/vfio/pci-quirks.c          |  617
> +++++++++++++++++++++++++++++++++++++++++
>  hw/vfio/pci.c                 |  145 ++++++----
>  hw/vfio/pci.h                 |    8 +
>  include/hw/vfio/vfio-common.h |    2
>  trace-events                  |   11 +
>  6 files changed, 824 insertions(+), 62 deletions(-)
>
>

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