Re: [vfio-users] Boot using second GPU?

[Rich Mingin (vfio-users)]

I'm using an Asus Z97 board and a Gigabyte Z97 board currently, and both
allow for switching the boot GPU between PCIE1, PCIE[2-5] or the iGPU. All
slots are one ACS group, though.

On Sun, Aug 7, 2016 at 10:14 AM, Rokas Kupstys  wrote:

> Thanks for reply. Since i am making a new build i am looking for proper
> motherboard. One i sided with is from asus, but it seems asus
> motherboards do not support switching primary GPU. I might go with
> gigabyte if there is no way to solve this. I am not sure yet though.
> Switching primary gpu in bios is ultimate solution. Directions i
> provided in earlier mail are workaround for people who do not have such
> capability. It is a tricky choice.. Go with beloved asus and suffer
> minor inconvenience or go with gigabyte.. Did you have any problems with
> gigabyte motherboard(s)?
>
>
> Rokas Kupstys
>
> On 2016.08.05 14:44, Hristo Iliev wrote:
> > Am 05.08.2016 10:22, schrieb Rokas Kupstys:
> >
> >> Okay this is unexpected luck. After more tinkering i got it to work!
> >> Here is my setup:
> >>
> >> * AMD FX-8350 CPU + Sabertooth 990FX R2 motherboard
> >> * :01:00.0 - gpu in first slot
> >> * :06:00.0 - gpu in third slot
> >> * UEFI on host and guest.
> >> * Archlinux
> >>
> >> In order to make host use non-boot GPU:
> >>
> >> 1. Add Kernel boot parameter "video=efifb:off". This makes kernel not
> >> use first gpu and boot messages appear on second gpu.
> >>
> >> 2. Bind first gpu (:01:00.0) to vfio-pci driver. I did this by
> >> adding line
> >>
> >>> options vfio-pci ids=1002:677B,1002:AA98
> >> to /etc/modprobe.d/kvm.conf. They are obtained from "lspci -n" which
> >> in my case show:
> >>
> >>> 01:00.0 0300: 1002:677B
> >>> 01:00.1 0403: 1002:AA98
> >> 3. Configure xorg to use second gpu (:06:00.0). I added file
> >> /etc/X11/xorg.conf.d/secondary-gpu.conf with contents:
> >>
> >>> Section "Device"
> >>> Identifier "Device0"
> >>> Driver "radeon"
> >>> VendorName "AMD Corporation"
> >>> BoardName  "AMD Secondary"
> >>> BusID  "PCI:6:0:0"
> >>> EndSection
> >> And thats it! Now when machine boots it shows POST messages and
> >> bootloader on first gpu, but as soon as boot option is selected
> >> display goes blank and kernel boot messages show on second gpu. After
> >> boot you can assign first gpu to VM as usual and it works.
> >> HELP REQUEST: could someone with intel hardware (ideally x99 chipset)
> >> test this method? I am planning a build and if this works i could
> >> settle with 28 lane cpu and save couple hundred dollars. Intel's 40
> >> lane cpus are way overpriced.. And with 28 lane cpus only first slot
> >> can run at x16 speed while other slots downgrade to x8 or less.
> >> Anyhow i would love to hear if this works on intel hardware.
> >>
> >
> > Hi,
> >
> > I have a Gigabyte GA-X99-UD4 motherboard and i7-5820K. There are two GPUs
> > in it - a GTX 970 for pass-through on 03:00.0 and a GT 730 as primary GPU
> > on 06:00.0. The PCIE slot of the GT is selected as primary video output
> > in the UEFI settings. All text and graphics output goes to it - the
> > output
> > of the GTX card remains off the entire time until the VM is booted. The X
> > server does see both cards but since the nvidia module is prevented from
> > binding to the GTX, X cannot use it and starts on the GT. No fiddling
> > with
> > the console driver parameters necessary.
> >
> > Distribution:
> >Arch Linux, 4.6.4-1-ARCH
> >
> > Kernel parameters:
> >... pci-stub.ids=10de:13c2,10de:0fbb,8086:8d20 nvidia-drm.modeset=1
> > ...
> >
> > /etc/modprobe.d/vfio.conf:
> >options vfio-pci ids=10de:13c2,10de:0fbb,8086:8d20
> >
> > /etc/mkinitcpio.conf:
> >...
> >MODULES="vfio vfio_iommu_type1 vfio_pci vfio_virqfd vfat aes_x86_64
> > crc32c_intel nvidia nvidia_modeset nvidia_uvm nvidia_drm"
> >...
> >
> > /etc/X11/xorg.conf.d/20-nvidia.conf:
> >Section "Device"
> > Identifier"Device0"
> > Driver"nvidia"
> > VendorName"NVIDIA Corporation"
> > Option "ConnectToAcpid"   "0"
> >EndSection
> >
> > The only problem with my setup is that the GTX is in PCIE_2, which works
> > as x8 with i7-5820K installed. I cannot fit the card in PCIE_1 because of
> > the oversized CPU cooler. This doesn't actually bug me at all as multiple
> > tests (for example, [1]) have shown negligible difference in gaming FPS
> > between PCI-e 3.0 x8 and x16. The GT card is in PCIE_4.
> >
> > Kind regards,
> > Hristo
> >
> > [1]
> > http://www.gamersnexus.net/guides/2488-pci-e-3-x8-vs-x16-
> performance-impact-on-gpus
> >
> >> Rokas Kupstys
> >>
> >> On 2016.08.05 10:34, Rokas Kupstys wrote:
> >>
> >> I think i got half-way there.. My primary gpu is at :01:00.0 and
> >> secondary on :06:00.0. I used following xorg config:
> >>
> >> Section "Device"
> >> Identifier "Device0"
> >> Driver "radeon"
> >> VendorName "AMD Corporation"
> >> 

Re: [vfio-users] Boot using second GPU?

[Rokas Kupstys]

Thanks for reply. Since i am making a new build i am looking for proper
motherboard. One i sided with is from asus, but it seems asus
motherboards do not support switching primary GPU. I might go with
gigabyte if there is no way to solve this. I am not sure yet though.
Switching primary gpu in bios is ultimate solution. Directions i
provided in earlier mail are workaround for people who do not have such
capability. It is a tricky choice.. Go with beloved asus and suffer
minor inconvenience or go with gigabyte.. Did you have any problems with
gigabyte motherboard(s)?


Rokas Kupstys

On 2016.08.05 14:44, Hristo Iliev wrote:
> Am 05.08.2016 10:22, schrieb Rokas Kupstys:
>
>> Okay this is unexpected luck. After more tinkering i got it to work!
>> Here is my setup:
>>
>> * AMD FX-8350 CPU + Sabertooth 990FX R2 motherboard
>> * :01:00.0 - gpu in first slot
>> * :06:00.0 - gpu in third slot
>> * UEFI on host and guest.
>> * Archlinux
>>
>> In order to make host use non-boot GPU:
>>
>> 1. Add Kernel boot parameter "video=efifb:off". This makes kernel not
>> use first gpu and boot messages appear on second gpu.
>>
>> 2. Bind first gpu (:01:00.0) to vfio-pci driver. I did this by
>> adding line
>>
>>> options vfio-pci ids=1002:677B,1002:AA98
>> to /etc/modprobe.d/kvm.conf. They are obtained from "lspci -n" which
>> in my case show:
>>
>>> 01:00.0 0300: 1002:677B
>>> 01:00.1 0403: 1002:AA98
>> 3. Configure xorg to use second gpu (:06:00.0). I added file
>> /etc/X11/xorg.conf.d/secondary-gpu.conf with contents:
>>
>>> Section "Device"
>>> Identifier "Device0"
>>> Driver "radeon"
>>> VendorName "AMD Corporation"
>>> BoardName  "AMD Secondary"
>>> BusID  "PCI:6:0:0"
>>> EndSection
>> And thats it! Now when machine boots it shows POST messages and
>> bootloader on first gpu, but as soon as boot option is selected
>> display goes blank and kernel boot messages show on second gpu. After
>> boot you can assign first gpu to VM as usual and it works.
>> HELP REQUEST: could someone with intel hardware (ideally x99 chipset)
>> test this method? I am planning a build and if this works i could
>> settle with 28 lane cpu and save couple hundred dollars. Intel's 40
>> lane cpus are way overpriced.. And with 28 lane cpus only first slot
>> can run at x16 speed while other slots downgrade to x8 or less.
>> Anyhow i would love to hear if this works on intel hardware.
>>
>
> Hi,
>
> I have a Gigabyte GA-X99-UD4 motherboard and i7-5820K. There are two GPUs
> in it - a GTX 970 for pass-through on 03:00.0 and a GT 730 as primary GPU
> on 06:00.0. The PCIE slot of the GT is selected as primary video output
> in the UEFI settings. All text and graphics output goes to it - the
> output
> of the GTX card remains off the entire time until the VM is booted. The X
> server does see both cards but since the nvidia module is prevented from
> binding to the GTX, X cannot use it and starts on the GT. No fiddling
> with
> the console driver parameters necessary.
>
> Distribution:
>Arch Linux, 4.6.4-1-ARCH
>
> Kernel parameters:
>... pci-stub.ids=10de:13c2,10de:0fbb,8086:8d20 nvidia-drm.modeset=1
> ...
>
> /etc/modprobe.d/vfio.conf:
>options vfio-pci ids=10de:13c2,10de:0fbb,8086:8d20
>
> /etc/mkinitcpio.conf:
>...
>MODULES="vfio vfio_iommu_type1 vfio_pci vfio_virqfd vfat aes_x86_64
> crc32c_intel nvidia nvidia_modeset nvidia_uvm nvidia_drm"
>...
>
> /etc/X11/xorg.conf.d/20-nvidia.conf:
>Section "Device"
> Identifier"Device0"
> Driver"nvidia"
> VendorName"NVIDIA Corporation"
> Option "ConnectToAcpid"   "0"
>EndSection
>
> The only problem with my setup is that the GTX is in PCIE_2, which works
> as x8 with i7-5820K installed. I cannot fit the card in PCIE_1 because of
> the oversized CPU cooler. This doesn't actually bug me at all as multiple
> tests (for example, [1]) have shown negligible difference in gaming FPS
> between PCI-e 3.0 x8 and x16. The GT card is in PCIE_4.
>
> Kind regards,
> Hristo
>
> [1]
> http://www.gamersnexus.net/guides/2488-pci-e-3-x8-vs-x16-performance-impact-on-gpus
>
>> Rokas Kupstys
>>
>> On 2016.08.05 10:34, Rokas Kupstys wrote:
>>
>> I think i got half-way there.. My primary gpu is at :01:00.0 and
>> secondary on :06:00.0. I used following xorg config:
>>
>> Section "Device"
>> Identifier "Device0"
>> Driver "radeon"
>> VendorName "AMD Corporation"
>> BoardName  "AMD Secondary"
>> BusID  "PCI:6:0:0"
>> EndSection
>>
>> After booting :06:00.0 was still bound to vfio-pci (im yet to sort
>> it out why as i removed modprobe configs and kernel parameters) and i
>> ran following script to bind gpu to correct driver:
>>
>> #!/bin/bash
>>
>> unbind() {
>> dev=$1
>> if [ -e /sys/bus/pci/devices/${dev}/driver ]; then
>> echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind
>> while [ -e /sys/bus/pci/devices/${dev}/driver ]; do
>> sleep 0.1

Re: [vfio-users] Boot using second GPU?

[Hristo Iliev]

Am 05.08.2016 10:22, schrieb Rokas Kupstys:

Okay this is unexpected luck. After more tinkering i got it to work! 
Here is my setup:


* AMD FX-8350 CPU + Sabertooth 990FX R2 motherboard
* :01:00.0 - gpu in first slot
* :06:00.0 - gpu in third slot
* UEFI on host and guest.
* Archlinux

In order to make host use non-boot GPU:

1. Add Kernel boot parameter "video=efifb:off". This makes kernel not 
use first gpu and boot messages appear on second gpu.


2. Bind first gpu (:01:00.0) to vfio-pci driver. I did this by 
adding line



options vfio-pci ids=1002:677B,1002:AA98
to /etc/modprobe.d/kvm.conf. They are obtained from "lspci -n" which in 
my case show:



01:00.0 0300: 1002:677B
01:00.1 0403: 1002:AA98
3. Configure xorg to use second gpu (:06:00.0). I added file 
/etc/X11/xorg.conf.d/secondary-gpu.conf with contents:



Section "Device"
Identifier "Device0"
Driver "radeon"
VendorName "AMD Corporation"
BoardName  "AMD Secondary"
BusID  "PCI:6:0:0"
EndSection
And thats it! Now when machine boots it shows POST messages and 
bootloader on first gpu, but as soon as boot option is selected display 
goes blank and kernel boot messages show on second gpu. After boot you 
can assign first gpu to VM as usual and it works.
HELP REQUEST: could someone with intel hardware (ideally x99 chipset) 
test this method? I am planning a build and if this works i could 
settle with 28 lane cpu and save couple hundred dollars. Intel's 40 
lane cpus are way overpriced.. And with 28 lane cpus only first slot 
can run at x16 speed while other slots downgrade to x8 or less. Anyhow 
i would love to hear if this works on intel hardware.




Hi,

I have a Gigabyte GA-X99-UD4 motherboard and i7-5820K. There are two 
GPUs
in it - a GTX 970 for pass-through on 03:00.0 and a GT 730 as primary 
GPU

on 06:00.0. The PCIE slot of the GT is selected as primary video output
in the UEFI settings. All text and graphics output goes to it - the 
output
of the GTX card remains off the entire time until the VM is booted. The 
X

server does see both cards but since the nvidia module is prevented from
binding to the GTX, X cannot use it and starts on the GT. No fiddling 
with

the console driver parameters necessary.

Distribution:
   Arch Linux, 4.6.4-1-ARCH

Kernel parameters:
   ... pci-stub.ids=10de:13c2,10de:0fbb,8086:8d20 nvidia-drm.modeset=1 
...


/etc/modprobe.d/vfio.conf:
   options vfio-pci ids=10de:13c2,10de:0fbb,8086:8d20

/etc/mkinitcpio.conf:
   ...
   MODULES="vfio vfio_iommu_type1 vfio_pci vfio_virqfd vfat aes_x86_64 
crc32c_intel nvidia nvidia_modeset nvidia_uvm nvidia_drm"

   ...

/etc/X11/xorg.conf.d/20-nvidia.conf:
   Section "Device"
Identifier"Device0"
Driver"nvidia"
VendorName"NVIDIA Corporation"
Option "ConnectToAcpid"   "0"
   EndSection

The only problem with my setup is that the GTX is in PCIE_2, which works
as x8 with i7-5820K installed. I cannot fit the card in PCIE_1 because 
of
the oversized CPU cooler. This doesn't actually bug me at all as 
multiple

tests (for example, [1]) have shown negligible difference in gaming FPS
between PCI-e 3.0 x8 and x16. The GT card is in PCIE_4.

Kind regards,
Hristo

[1] 
http://www.gamersnexus.net/guides/2488-pci-e-3-x8-vs-x16-performance-impact-on-gpus



Rokas Kupstys

On 2016.08.05 10:34, Rokas Kupstys wrote:

I think i got half-way there.. My primary gpu is at :01:00.0 and
secondary on :06:00.0. I used following xorg config:

Section "Device"
Identifier "Device0"
Driver "radeon"
VendorName "AMD Corporation"
BoardName  "AMD Secondary"
BusID  "PCI:6:0:0"
EndSection

After booting :06:00.0 was still bound to vfio-pci (im yet to sort
it out why as i removed modprobe configs and kernel parameters) and i
ran following script to bind gpu to correct driver:

#!/bin/bash

unbind() {
dev=$1
if [ -e /sys/bus/pci/devices/${dev}/driver ]; then
echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind
while [ -e /sys/bus/pci/devices/${dev}/driver ]; do
sleep 0.1
done
fi
}

bind() {
dev=$1
driver=$2
vendor=$(cat /sys/bus/pci/devices/${dev}/vendor)
device=$(cat /sys/bus/pci/devices/${dev}/device)
echo "${vendor} ${device}" > /sys/bus/pci/drivers/${driver}/new_id
echo "$dev" > /sys/bus/pci/drivers/${driver}/bind
}

unbind ":06:00.0"
bind ":06:00.0" "radeon"
#unbind ":01:00.0"

After restarting sddm.service (display manager) i could switch to
secondary gpu and log in to desktop. All worked. Problem is i can not
unbind :01:00.0 so i could pass-through it. Attempt to unbind 
driver

resulted in display freezing. Even secondary gpu froze.

Rokas Kupstys

On 2016.08.05 04:55, Nicolas Roy-Renaud wrote:

That's something you should fix in the BIOS. The boot GPU is special
because the motherboard has to use it to display things such as POST
messages and such, so it's already "tainted" by the time the kernel
gets a hold of it. I 

Re: [vfio-users] Boot using second GPU?

[Rokas Kupstys]

Okay this is unexpected luck. After more tinkering i got it to work!
Here is my setup:

  * AMD FX-8350 CPU + Sabertooth 990FX R2 motherboard
  * :01:00.0 - gpu in first slot
  * :06:00.0 - gpu in third slot
  * UEFI on host and guest.
  * Archlinux

In order to make host use non-boot GPU:

1. Add Kernel boot parameter "video=efifb:off". This makes kernel not
use first gpu and boot messages appear on second gpu.

2. Bind first gpu (:01:00.0) to vfio-pci driver. I did this by
adding line

> options vfio-pci ids=*1002:677b*,*1002:aa98*
to /etc/modprobe.d/kvm.conf. They are obtained from "lspci -n" which in
my case show:

> 01:00.0 0300: *1002:677b*
> 01:00.1 0403: *1002:aa98*
3. Configure xorg to use second gpu (*:06:00.0*). I added file
/etc/X11/xorg.conf.d/secondary-gpu.conf with contents:

> Section "Device"
> Identifier "Device0"
> Driver "radeon"
> VendorName "AMD Corporation"
> BoardName  "AMD Secondary"
> BusID  "*PCI:6:0:0*"
> EndSection
And thats it! Now when machine boots it shows POST messages and
bootloader on first gpu, but as soon as boot option is selected display
goes blank and kernel boot messages show on second gpu. After boot you
can assign first gpu to VM as usual and it works.

***Help request: *could someone with intel hardware (ideally x99
chipset) test this method? I am planning a build and if this works i
could settle with 28 lane cpu and save couple hundred dollars. Intel's
40 lane cpus are way overpriced.. And with 28 lane cpus only first slot
can run at x16 speed while other slots downgrade to x8 or less. Anyhow i
would love to hear if this works on intel hardware.

Rokas Kupstys

On 2016.08.05 10:34, Rokas Kupstys wrote:
> I think i got half-way there.. My primary gpu is at :01:00.0 and
> secondary on :06:00.0. I used following xorg config:
>
> Section "Device"
> Identifier "Device0"
> Driver "radeon"
> VendorName "AMD Corporation"
> BoardName  "AMD Secondary"
> BusID  "PCI:6:0:0"
> EndSection
>
> After booting :06:00.0 was still bound to vfio-pci (im yet to sort
> it out why as i removed modprobe configs and kernel parameters) and i
> ran following script to bind gpu to correct driver:
>
> #!/bin/bash
>
> unbind() {
> dev=$1
> if [ -e /sys/bus/pci/devices/${dev}/driver ]; then
> echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind
> while [ -e /sys/bus/pci/devices/${dev}/driver ]; do
> sleep 0.1
> done
> fi
> }
>
> bind() {
> dev=$1
> driver=$2
> vendor=$(cat /sys/bus/pci/devices/${dev}/vendor)
> device=$(cat /sys/bus/pci/devices/${dev}/device)
> echo "${vendor} ${device}" > /sys/bus/pci/drivers/${driver}/new_id
> echo "$dev" > /sys/bus/pci/drivers/${driver}/bind
> }
>
> unbind ":06:00.0"
> bind ":06:00.0" "radeon"
> #unbind ":01:00.0"
>
> After restarting sddm.service (display manager) i could switch to
> secondary gpu and log in to desktop. All worked. Problem is i can not
> unbind :01:00.0 so i could pass-through it. Attempt to unbind driver
> resulted in display freezing. Even secondary gpu froze.
>
>
> Rokas Kupstys
>
> On 2016.08.05 04:55, Nicolas Roy-Renaud wrote:
>> That's something you should fix in the BIOS. The boot GPU is special
>> because the motherboard has to use it to display things such as POST
>> messages and such, so it's already "tainted" by the time the kernel
>> gets a hold of it. I had to put my guest GPU on my motherboard's
>> second PCI slot because of that (can't change the boot GPU in the BIOS
>> settings), which is pretty unconveinient because it blocks access to
>> most of my sata ports.
>>
>> If there's a way to cleanly pass the boot GPU to a VM, I don't know
>> about it. I'd be interested to know too, however.
>>
>> - Nicolas
>>
>> On 2016-08-04 13:59, Rokas Kupstys wrote:
>>> Hey is it possible to make kernel use GPU other than one that is in
>>> first slot? If so - how?
>>>
>>> I have multiple PCIe slots but only first can run at max speed so i
>>> would like to use it for VGA passthrough. However if i put powerful GPU
>>> into the first slot - linux boots using that GPU. I would like to make
>>> kernel use GPU in slot 3. So result should be bios and bootloader
>>> running on gpu in slot #1, but kernel should use gpu in slot #3. I tried
>>> binding first gpu to vfio-pci driver hoping kernel would use next
>>> available gpu. That did not work, i could see one line with systemd
>>> version in low-res console (normally its high-res). I also tryed
>>> fbcon=map:1234 (not exactly being sure what im doing) but that yielded
>>> black screen. Not sure what else i could try.
>>>
>> ___
>> vfio-users mailing list
>> vfio-users@redhat.com
>> https://www.redhat.com/mailman/listinfo/vfio-users
>>
> ___
> vfio-users mailing list
> 

Re: [vfio-users] Boot using second GPU?

[Rokas Kupstys]

I think i got half-way there.. My primary gpu is at :01:00.0 and
secondary on :06:00.0. I used following xorg config:

Section "Device"
Identifier "Device0"
Driver "radeon"
VendorName "AMD Corporation"
BoardName  "AMD Secondary"
BusID  "PCI:6:0:0"
EndSection

After booting :06:00.0 was still bound to vfio-pci (im yet to sort
it out why as i removed modprobe configs and kernel parameters) and i
ran following script to bind gpu to correct driver:

#!/bin/bash

unbind() {
dev=$1
if [ -e /sys/bus/pci/devices/${dev}/driver ]; then
echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind
while [ -e /sys/bus/pci/devices/${dev}/driver ]; do
sleep 0.1
done
fi
}

bind() {
dev=$1
driver=$2
vendor=$(cat /sys/bus/pci/devices/${dev}/vendor)
device=$(cat /sys/bus/pci/devices/${dev}/device)
echo "${vendor} ${device}" > /sys/bus/pci/drivers/${driver}/new_id
echo "$dev" > /sys/bus/pci/drivers/${driver}/bind
}

unbind ":06:00.0"
bind ":06:00.0" "radeon"
#unbind ":01:00.0"

After restarting sddm.service (display manager) i could switch to
secondary gpu and log in to desktop. All worked. Problem is i can not
unbind :01:00.0 so i could pass-through it. Attempt to unbind driver
resulted in display freezing. Even secondary gpu froze.


Rokas Kupstys

On 2016.08.05 04:55, Nicolas Roy-Renaud wrote:
> That's something you should fix in the BIOS. The boot GPU is special
> because the motherboard has to use it to display things such as POST
> messages and such, so it's already "tainted" by the time the kernel
> gets a hold of it. I had to put my guest GPU on my motherboard's
> second PCI slot because of that (can't change the boot GPU in the BIOS
> settings), which is pretty unconveinient because it blocks access to
> most of my sata ports.
>
> If there's a way to cleanly pass the boot GPU to a VM, I don't know
> about it. I'd be interested to know too, however.
>
> - Nicolas
>
> On 2016-08-04 13:59, Rokas Kupstys wrote:
>> Hey is it possible to make kernel use GPU other than one that is in
>> first slot? If so - how?
>>
>> I have multiple PCIe slots but only first can run at max speed so i
>> would like to use it for VGA passthrough. However if i put powerful GPU
>> into the first slot - linux boots using that GPU. I would like to make
>> kernel use GPU in slot 3. So result should be bios and bootloader
>> running on gpu in slot #1, but kernel should use gpu in slot #3. I tried
>> binding first gpu to vfio-pci driver hoping kernel would use next
>> available gpu. That did not work, i could see one line with systemd
>> version in low-res console (normally its high-res). I also tryed
>> fbcon=map:1234 (not exactly being sure what im doing) but that yielded
>> black screen. Not sure what else i could try.
>>
>
> ___
> vfio-users mailing list
> vfio-users@redhat.com
> https://www.redhat.com/mailman/listinfo/vfio-users
>


___
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users

Re: [vfio-users] Boot using second GPU?

[Nicolas Roy-Renaud]

That's something you should fix in the BIOS. The boot GPU is special 
because the motherboard has to use it to display things such as POST 
messages and such, so it's already "tainted" by the time the kernel gets 
a hold of it. I had to put my guest GPU on my motherboard's second PCI 
slot because of that (can't change the boot GPU in the BIOS settings), 
which is pretty unconveinient because it blocks access to most of my 
sata ports.


If there's a way to cleanly pass the boot GPU to a VM, I don't know 
about it. I'd be interested to know too, however.


- Nicolas

On 2016-08-04 13:59, Rokas Kupstys wrote:

Hey is it possible to make kernel use GPU other than one that is in
first slot? If so - how?

I have multiple PCIe slots but only first can run at max speed so i
would like to use it for VGA passthrough. However if i put powerful GPU
into the first slot - linux boots using that GPU. I would like to make
kernel use GPU in slot 3. So result should be bios and bootloader
running on gpu in slot #1, but kernel should use gpu in slot #3. I tried
binding first gpu to vfio-pci driver hoping kernel would use next
available gpu. That did not work, i could see one line with systemd
version in low-res console (normally its high-res). I also tryed
fbcon=map:1234 (not exactly being sure what im doing) but that yielded
black screen. Not sure what else i could try.



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