Arch Linux

aw

Member

Registered: 2013-10-04

Posts: 921

Website

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Am i right in assuming i can't enable Spice at all on nividia passthrough? I'd love to hotplug usb devices to the VM.

Why do you need spice to have hotplug usb devices?  Do you mean hotplug usb from remote clients?  AFAIK, spice requires adding a QXL video head.  If you're using Win8+/OVMF, then that's possible and you can even have the GPU render into the QXL display.  However, you might as well be doing software 3D with the speed you'll get.  You can also disable the QXL display in the guest, I've done this to experiment with piping the audio back to the host over spice.  I don't see why USB wouldn't work the same.  However, I wonder what the value is of doing USB passthrough via spice when you're sitting within a monitor cable length of the host and therefore able to just hotplug usb via virt-manager.

---

http://vfio.blogspot.com
Looking for a more open forum to discuss vfio related uses?  Try https://www.redhat.com/mailman/listinfo/vfio-users

DelusionalLogic

Member

Registered: 2013-05-07

Posts: 40

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Why do you need spice to have hotplug usb devices?  Do you mean hotplug usb from remote clients?  AFAIK, spice requires adding a QXL video head.  If you're using Win8+/OVMF, then that's possible and you can even have the GPU render into the QXL display.  However, you might as well be doing software 3D with the speed you'll get.  You can also disable the QXL display in the guest, I've done this to experiment with piping the audio back to the host over spice.  I don't see why USB wouldn't work the same.  However, I wonder what the value is of doing USB passthrough via spice when you're sitting within a monitor cable length of the host and therefore able to just hotplug usb via virt-manager.

I was under the impression that you would have to reboot the VM to attach a new USB device to it. Is that wrong? If so, then how would i go about hotplugging passthrough devices into the vm. It's all on my local qemu:///system.

I tried virsh attach-device usb-dev.xml (with a correctly formatted xml file specifying my phone vendor and product id) sadly that had no effect on my vm.

I see no option in virt-manager to do this.

EDIT: Okay, so it works fine with virsh attach-device (the problem was that qualcomm sneakily changes product id every time you switch mode, i was using the wrong id). I'd still love to know how this is done in virt-manager.

Last edited by DelusionalLogic (2015-01-19 21:33:51)

aw

Member

Registered: 2013-10-04

Posts: 921

Website

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

I was under the impression that you would have to reboot the VM to attach a new USB device to it. Is that wrong? If so, then how would i go about hotplugging passthrough devices into the vm. It's all on my local qemu:///system.

I tried virsh attach-device usb-dev.xml (with a correctly formatted xml file specifying my phone vendor and product id) sadly that had no effect on my vm.

I see no option in virt-manager to do this.

Hotplug USB should work w/o spice.

View -> Details

Add Hardware -> USB Host device -> [select] -> Finish

---

http://vfio.blogspot.com
Looking for a more open forum to discuss vfio related uses?  Try https://www.redhat.com/mailman/listinfo/vfio-users

DelusionalLogic

Member

Registered: 2013-05-07

Posts: 40

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Hotplug USB should work w/o spice.

View -> Details

Add Hardware -> USB Host device -> [select] -> Finish

Ahh, the problem here is that virt-manager is as dumb as me. It isn't updating the product id of the device, so it's trying to add 0x6765 when the correct id is 0x6764. In static applications (such as a controller) that shouldn't be an issue. thanks.

myweb

Member

Registered: 2013-07-13

Posts: 69

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

With i915 is blacklisted I got host system hanged when run two Guests

DelusionalLogic

Member

Registered: 2013-05-07

Posts: 40

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

aw, you mentioned audio and spice. Is that the only way to get audio back to the host and out through the same speakers?

I'm trying to do it right now, and the ICH6 driver is working (i can see it in windows) but nothing is playing from the host, and pulse isn't detecting a source. I would really prefer not to configure pulse as a system wide service.

Last edited by DelusionalLogic (2015-01-20 00:29:02)

redger

Member

Registered: 2014-02-26

Posts: 15

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Help
I am trying to install Win 7 via ovmf / uefi. Win 8 works nicely via ovmf in Libvirt / virt-manager but Win 7 does not
The machine is running Ubuntu 14.04 Trusty LTS, patched to support KVM VMs with VGA passthrough - which has been working well for about a year. And a Win8 uefi VM was easy to install. But I want Win 7
I found NBH reference to success at https://bbs.archlinux.org/viewtopic.php … 0#p1483550 and I tried several variations of that method (starting with a Win 7 image which is known to work for BIOS install)
ie. create a new image including Virtio and QXL drivers using wintoolkit, create a Fat32 partition on a GPT disk, copy the image files to the new partition and then start the VM for install

Somehow I always wind up with BCD issues .. or worse eg.

File:  \EFI\Microsoft\Boot\BCD
Status: 0x0000178
Info: An error occurred while attempting to read the boot configuration data

I've looked at the BCD using bcd-edit and cannot see anything obviously wrong ... but then I'm an absolute neophyte so who knows

The EFI shell is available ..... but I cannot find any useful commands and executing \efi\boot\bootx64.efi just takes me back to the same error - as you might expect

Can anyone advise a way forward ?

DelusionalLogic

Member

Registered: 2013-05-07

Posts: 40

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

I just noticed something, and i can't be the only one.

I'm getting really screwy screen updates on the host. If i switch between pages in my PDF reader the display will be one input behind (if i pgup and then pgdown it will go up when i click down, but then after a couple of seconds it goes down). In vim i'm getting 2 lines highlighted at once, and in firefox sometimes my keypresses does the same as the PDF reader (so i write hello, and the h appears when i press e, then the e when i press l and so on).

It seems to have something to do with the VM running, because it doesn't really happen when it's off. I really wish i could turn off the card (at least the fan, the card does seem to go into D3) when i don't need it.

aw

Member

Registered: 2013-10-04

Posts: 921

Website

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

I just noticed something, and i can't be the only one.

I'm getting really screwy screen updates on the host.[snip]

Are you using synergy?  I had some strange mouse behavior in chrome that was resolved by using the upstream (paid) version of synergy rather than the distro version.  Otherwise I don't notice anything like you're describing with a VM running.  I also don't try to share mouse/keyboard except through synergy.

---

http://vfio.blogspot.com
Looking for a more open forum to discuss vfio related uses?  Try https://www.redhat.com/mailman/listinfo/vfio-users

walkindude

Member

Registered: 2012-03-04

Posts: 29

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Tried to switch GPUs on my mobo:

so, now we have

HD 6850, x16, blue
R9 270, x4, black

after reboot can't load to my kernel, it just stuck on
grub complaining about diskfilter writes (system's on lvm, just wait or press any key -> it goes away, and system boots as expected)

It doesn't matter if I removed pci-ids or not.

But I managed to boot in ARCH-kernel, and now I get in dmesg:

walkindude@Desktop> sudo dmesg | grep -i AMD-Vi                                                                                ~
[sudo] password for walkindude:
[    0.107871] AMD-Vi: device: 00:00.2 cap: 0040 seg: 0 flags: 3e info 1300
[    0.107872] AMD-Vi:        mmio-addr: 00000000feb20000
[    0.107883] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 00:00.0 flags: 00
[    0.107885] AMD-Vi:   DEV_RANGE_END         devid: 00:00.2
[    0.107886] AMD-Vi:   DEV_SELECT             devid: 00:02.0 flags: 00
[    0.107887] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 01:00.0 flags: 00
[    0.107888] AMD-Vi:   DEV_RANGE_END         devid: 01:00.1
[    0.107889] AMD-Vi:   DEV_SELECT             devid: 00:11.0 flags: 00
[    0.107890] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 00:12.0 flags: 00
[    0.107891] AMD-Vi:   DEV_RANGE_END         devid: 00:12.2
[    0.107892] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 00:13.0 flags: 00
[    0.107893] AMD-Vi:   DEV_RANGE_END         devid: 00:13.2
[    0.107894] AMD-Vi:   DEV_SELECT             devid: 00:14.0 flags: d7
[    0.107895] AMD-Vi:   DEV_SELECT             devid: 00:14.3 flags: 00
[    0.107896] AMD-Vi:   DEV_SELECT             devid: 00:14.4 flags: 00
[    0.107898] AMD-Vi:   DEV_ALIAS_RANGE         devid: 02:00.0 flags: 00 devid_to: 00:14.4
[    0.107898] AMD-Vi:   DEV_RANGE_END         devid: 02:1f.7
[    0.107906] AMD-Vi:   DEV_SELECT             devid: 00:14.5 flags: 00
[    0.107907] AMD-Vi:   DEV_SELECT             devid: 00:15.0 flags: 00
[    0.107908] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 03:00.0 flags: 00
[    0.107909] AMD-Vi:   DEV_RANGE_END         devid: 03:00.1
[    0.107910] AMD-Vi:   DEV_SELECT_RANGE_START     devid: 00:16.0 flags: 00
[    0.107911] AMD-Vi:   DEV_RANGE_END         devid: 00:16.2
[    0.107912] AMD-Vi:   DEV_SPECIAL(IOAPIC[0])        devid: 00:14.0
[    0.107914] AMD-Vi:   DEV_SPECIAL(HPET[0])        devid: 00:14.0
[    0.107915] AMD-Vi:   DEV_SPECIAL(IOAPIC[255])        devid: 00:00.1
[    2.908990] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
[    2.908992] AMD-Vi: Interrupt remapping enabled
[    2.909114] AMD-Vi: Initialized for Passthrough Mode
[    3.045906] AMD-Vi: Completion-Wait loop timed out
[    3.156248] AMD-Vi: Completion-Wait loop timed out
[    3.266509] AMD-Vi: Completion-Wait loop timed out
[    3.376798] AMD-Vi: Completion-Wait loop timed out
[    3.487084] AMD-Vi: Completion-Wait loop timed out
[    3.597349] AMD-Vi: Completion-Wait loop timed out
[    3.707628] AMD-Vi: Completion-Wait loop timed out
[    3.817917] AMD-Vi: Completion-Wait loop timed out
[    3.928191] AMD-Vi: Completion-Wait loop timed out
[    4.017795] AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=03:00.0 address=0x00000002331e88e0]
[    4.017805] AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=03:00.0 address=0x00000002331e8900]
[    4.017810] AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=03:00.0 address=0x00000002331e8930]

If I switch GPUs back,my kernel boots, but during this process I'm seing something strange (can't find it later in logs, so I shot it by my phone camera)
http://rghost.net/private/60392304/15d7 … e5413.view
These two line were present on all my attempts (on this and previous pages of current topic)

In dmesg after

AMD-Vi: Initialized for Passthrough Mode

nothing, no lines about

Completion-Wait loop timed out or

Event logged [IOTLB_INV_TIMEOUT device=03:00.0 address=0x00000002331e8900]

UEFI bios on my mobo (M5A97 PRO) is the latest available: 1604. I'd flashed it a long time ago, during the installation of FX CPU.

What is wrong here? Should I buy the second revision or completely another AM3+ motherboard? or smth wrong in my settings?

So no Windows with Seabios on this configuration?

walkindude@Desktop> sudo lspci -v -s 3:00.0                                                                                     ~
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Barts PRO [Radeon HD 6850] (prog-if 00 [VGA controller])
    Subsystem: PC Partner Limited / Sapphire Technology Device e174
    Flags: fast devsel, IRQ 16
    Memory at c0000000 (64-bit, prefetchable) [size=256M]
    Memory at fe820000 (64-bit, non-prefetchable) [size=128K]
    I/O ports at c000 [size=256]
    Expansion ROM at fe800000 [disabled] [size=128K]
    Capabilities: [50] Power Management version 3
    Capabilities: [58] Express Legacy Endpoint, MSI 00
    Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
    Capabilities: [150] Advanced Error Reporting
    Kernel driver in use: vfio-pci
    Kernel modules: radeon

meaning no MSI support currently enabled, am I right? Could I enable it?

Also tried these patches
http://vfio.blogspot.co.uk/2014/08/fixe … uests.html
the same,
AFTER choosing device to boot - black screen

Last edited by walkindude (2015-01-20 23:16:43)

DelusionalLogic

Member

Registered: 2013-05-07

Posts: 40

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Okay then. I guess i jumped the gun a bit. I noticed that it wasn't happening earlier, when the VM was down for a reboot, but was now. After turning off the VM and playing around a bit it's actually vims fault.

When i do some copy and paste operations in vim (or whatever it feels like it sometimes) it will start to not refresh a line on the screen. It seems that when this happens i have the issues in Zathura as well (my pdf reader). Quitting Vim while the issue is ongoing actually completely fixes the issue in zathura. Very strange, not the VM's fault though. Even stranger is that i've never had this problem before switching my graphics cards (the 660 was my main before), so either the VM does have some effect or the video card is acting up.

EDIT: Tried it again, and the issue happened again. It seems to be linked to the usage of the virtual machine as well... What's the current status on CPU pinning and hugepages? are either of those known to cause problems if on/off?

Last edited by DelusionalLogic (2015-01-20 20:10:39)

myweb

Member

Registered: 2013-07-13

Posts: 69

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

aw
Could you please specify what log files, actions should be performed in order to collect necessary information - why virtual machine is not booted (screen is not turned on) if Nvidia GT640 is set as primary VGA device (via vfio x-vga=on).

Thank you in advance!

MrTUX-10

Member

Registered: 2015-01-06

Posts: 12

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Thank you all nbhs, and everyone else for your contributions to this thread! It has been so helpful getting everything setup. I've had my VM running for a while now, everything runs pretty damn well. I'm using an Intel 4820k, EVGA-X79 Motherboard, GTX,970 with the latest drivers. I was wondering if anyone could provide some insight on vcpu pinning, i have cset and cgroups setup, and the performance on the machine is actually pretty awesome, but with that, making it even faster is always better, I have looked around a bit from googling, and everthing seems to point to an xml file, however I didn't create it using libvirt, I launch it from as script. Does anyone have any idea how you would pin the vpcu's? That would be so helpful!

Thanks in advance!

walkindude

Member

Registered: 2012-03-04

Posts: 29

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Tried one last solution (why I didn't do it earlier?). Booted in ARCH kernel (with no additional patching at all), and NO black screen: Windows DVD boots as expected!!
So I guess something wrong either in -ck patches or uksm.

No, nothing wrong with them:
just removed custom dsdt table from kernel and now no black screen

Last edited by walkindude (2015-01-21 16:55:28)

walkindude

Member

Registered: 2012-03-04

Posts: 29

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Catalyst installs without problems, I have 1920x1080 on guest.
Windows 10 Build 9888
Seabios for now, because desired card hasn't UEFI bios (6850) or maybe I don't know how to get one. Had seen on youtube how they managed to do it with 7000 series videocard, but for me it didn't work.

redger

Member

Registered: 2014-02-26

Posts: 15

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

@walkindude
for UEFI bios on older AMD cards, try here http://www.overclock.net/t/1474306/rade … ios-thread ... worked for me

walkindude

Member

Registered: 2012-03-04

Posts: 29

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

@redger
Yep, saw it, but not very thorough.. didn't find Sapphire 6850 1 gb, and moved to seabios then

tried it, now getting

walkindude@Desktop> ~/rom-parser/rom-parser uefi.rom                                                                                                                                                                                                                  ~/Dropbox
Valid ROM signature found @0h, PCIR offset 1ech
    PCIR: type 0, vendor: 1002, device: 6739, class: 030000
    PCIR: revision 0, vendor revision: d0a
Valid ROM signature found @fa00h, PCIR offset 1ch
    PCIR: type 3, vendor: 1002, device: 6779, class: 030000
    PCIR: revision 0, vendor revision: 0
        EFI: Signature Valid
    Last image

but isn't 1002:6779 a 6450? so I just lowered my card?)

Besides for now system is quite stable and I've already install a lot of things and don't really want to make any more experiments and reinstall everything again.

Thanks anyway

----

One question remains:

Arch:

Screen 1 -- Screen 2 <-- hdmi1
Synergy server

Windows:

Screen 2 <-- hdmi2
Synergy client

Synergys on both system work, I can use my host mouse / keyboard in guest, but

- If I place hosts horizontally I can't move to arch at all.

- If I place windows above, then at start I can move mouse in arch, but after it goes up in windows - it'll never return.

4kGamer

Member

Registered: 2014-10-29

Posts: 88

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

one question; these days I am enjoying my successful VM Although I don't have to much time. Exams in exactly one month! Therefore I don't want to break something that works. However having archlinux as a host, I am kinda relying on system updates

So: How safe is it to update lnux without breaking the VM?

walkindude

Member

Registered: 2012-03-04

Posts: 29

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

@4kGamer
Arch doesn't force you to update and will live one month and more happily without them.

As for me:
built new versions of kernel, qemu, libvirt several times, also upgraded other packages as well - all mistakes with VM were my own, not some buggy update

Also there is /var/cache/pacman/pkg is something goes terribly wrong

Last edited by walkindude (2015-01-22 13:12:02)

KKF

Member

Registered: 2015-01-21

Posts: 3

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Hey guys,

I am new to all this and have wanted to try it out for a while as a learning experience for myself.  I have the budget to build a PC just for this.  For starters I would like to have one Windows 8 VM and Elementary OS as host; if possible.  Eventually I would like to have an OSX VM and a Windows VM, though I understand how difficult that can be.

With anything of this magnitude I want to make sure I buy the right components for the job.  The only components I own at this point are a 660 ti gpu and a R4 case.  I will probably buy a 970 gpu at some point in the future but no rush at this point.  Any advise on what to buy for MOBO, CPU, and Ram?  Should I buy two separate SSD for each VM?  I have a server that hosts all my documents and files so don't need to much space on those SSD's. 

The OSX VM would mainly be used for Photoshop as my girlfriend prefers the layout of Photoshop in OSX to Windows. The Windows VM would be used for gaming.  I play Heroes of the Storm and SC2.  So nothing to intensive.

While I really do not have a budget for this I don't want to spend 2000 dollars either as it really is for learning and the challenge of putting this together.  So what would be my best options for a MOBO, CPU, and Ram? 

After I buy everything I plan to do an extensive how to on cost and time it took me, a novice, to do this.

Thanks!

Last edited by KKF (2015-01-22 18:57:21)

4kGamer

Member

Registered: 2014-10-29

Posts: 88

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

@dude Thank you. I tried and everything is still working. Phew

@KKF: Make sure you get the motherboard right. Everything else depends on you.

I use this one: ASROCK Z97 Extreme6

It has been recommended to me by the user Archer here in this thread and I couldn't be happier

Last edited by 4kGamer (2015-01-22 20:15:38)

aw

Member

Registered: 2013-10-04

Posts: 921

Website

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Hey guys,

I am new to all this and have wanted to try it out for a while as a learning experience for myself.  I have the budget to build a PC just for this.  For starters I would like to have one Windows 8 VM and Elementary OS as host; if possible.  Eventually I would like to have an OSX VM and a Windows VM, though I understand how difficult that can be.

With anything of this magnitude I want to make sure I buy the right components for the job.  The only components I own at this point are a 660 ti gpu and a R4 case.  I will probably buy a 970 gpu at some point in the future but no rush at this point.  Any advise on what to buy for MOBO, CPU, and Ram?  Should I buy two separate SSD for each VM?  I have a server that hosts all my documents and files so don't need to much space on those SSD's. 

The OSX VM would mainly be used for Photoshop as my girlfriend prefers the layout of Photoshop in OSX to Windows. The Windows VM would be used for gaming.  I play Heroes of the Storm and SC2.  So nothing to intensive.

While I really do not have a budget for this I don't want to spend 2000 dollars either as it really is for learning and the challenge of putting this together.  So what would be my best options for a MOBO, CPU, and Ram? 

After I buy everything I plan to do an extensive how to on cost and time it took me, a novice, to do this.

Thanks!

Use a Xeon E5 or better and non-Intel graphics for the host if you don't want to deal with patching your kernel for ACS or VGA arbitration (BTW, X99 PCH root port patch just posted).  Gigabyte motherboards seem to be the most configurable when it comes selecting a primary graphics device, which may be important if you end up with 3 graphics cards.  If you blow all your money on an over-spec'd GPU for your needs and skimp a "client" processor, you'll pay for it patching your kernel forever.  Also, make sure you scale your core count and memory for the intended usage.  If you want to game at the same time as your gf is photoshop'ing, then you need to be able to dedicate some cores to each VM.  Also, OSX w/ GPU assignment is not something a lot of people are doing, so be sure to do your research on whether it's really an option.  There are parts of getting OSX to work that cannot be discussed on forums like this.

---

http://vfio.blogspot.com
Looking for a more open forum to discuss vfio related uses?  Try https://www.redhat.com/mailman/listinfo/vfio-users

Denso

Member

Registered: 2014-08-30

Posts: 179

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

@aw :

Started recieving these after I upgraded to 3.19-rc1 and still reciving them on 3.19-rc5 :

[Thu Jan 22 23:13:54 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:13:54 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:55 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:13:55 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:55 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:13:55 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:56 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:13:56 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:56 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:13:56 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:57 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:13:57 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:58 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:13:58 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:58 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:13:58 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:59 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:13:59 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:13:59 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:13:59 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:00 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:00 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:00 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:00 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:01 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:01 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:01 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:01 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:02 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:02 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:03 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:03 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:03 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:03 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:04 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:04 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:04 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:04 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:05 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:05 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:05 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:05 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:06 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:06 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:07 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:07 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:07 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:07 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:08 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:08 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:08 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:08 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:09 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:09 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:09 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:09 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:10 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:10 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:10 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:10 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:11 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:11 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:12 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:12 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:12 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:12 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:13 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:13 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:13 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:13 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:14 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:14 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:14 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:14 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:15 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:15 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:16 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:16 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:16 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:16 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:17 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:17 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:17 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:17 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:18 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:18 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:18 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:18 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:19 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:19 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:19 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:19 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:20 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:20 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:21 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:21 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:21 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:21 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:22 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:22 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:22 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:22 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:23 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:23 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:23 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:23 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:24 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:24 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:25 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:25 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:25 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:25 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:26 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:26 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:26 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:26 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:27 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:27 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:27 2015] dmar: DRHD: handling fault status reg 302
[Thu Jan 22 23:14:27 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:28 2015] dmar: DRHD: handling fault status reg 402
[Thu Jan 22 23:14:28 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:28 2015] dmar: DRHD: handling fault status reg 502
[Thu Jan 22 23:14:28 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:29 2015] dmar: DRHD: handling fault status reg 602
[Thu Jan 22 23:14:29 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:30 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:30 2015] dmar: DMAR:[DMA Read] Request device [02:00.1] fault addr 10af25000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf11f000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf169000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf201000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf299000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf331000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf128000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf1c5000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf260000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf2fa000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf466000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf11f000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf18b000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf22a000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf2cc000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf370000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DRHD: handling fault status reg 700
[Thu Jan 22 23:14:46 2015] dmar: DRHD: handling fault status reg 702
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf456000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DRHD: handling fault status reg 2
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf45f000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:46 2015] dmar: DRHD: handling fault status reg 102
[Thu Jan 22 23:14:46 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf45c000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:49 2015] dmar: DRHD: handling fault status reg 202
[Thu Jan 22 23:14:49 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bef2e000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:49 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bef7d000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:49 2015] dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr bf01c000
DMAR:[fault reason 06] PTE Read access is not set
[Thu Jan 22 23:14:49 2015] dmar: DMAR:[DMA Read] Request device [00:1a.0] fault addr ffffd000
DMAR:[fault reason 06] PTE Read access is not set

02:00.0 --> Nvidia GTX 770
00:1a.0 --> Intel X99 USB controller

Sometimes , the VM that has the GTX 770 throws code 43 and refuse to initialize the GPU when the above errors appear . Sometimes , it works perfectly even with the aforementioned errors .

mostlyharmless

Member

Registered: 2014-01-16

Posts: 72

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

So, I've been trying Arch instead of Slackware and have noticed a few odd things.  My qemu script is

QEMU_SDL_SAMPLES=2048 \
qemu-system-x86_64 -enable-kvm -M q35 -m 8192 -cpu host -smp 6,sockets=1,cores=6,threads=1 \
-bios /usr/share/qemu/bios.bin -vga none\
-device ioh3420,bus=pcie.0,addr=1c.0,multifunction=on,port=1,chassis=1,id=root.1 \
-device vfio-pci,host=03:00.0,bus=root.1,addr=00.0,multifunction=on,x-vga=on \
-drive file=/dev/mapper/cryptvg2-win7,id=disk,if=virtio \
-device piix4-ide,bus=pcie.0 \
-drive file=/dev/sr0,id=cddisk -device ide-cd,bus=ide.1,drive=cddisk \
-net vde -net nic,vlan=0,model=virtio \
-device ich9-intel-hda,bus=pcie.0,addr=1b.0,id=sound0 \
-device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 \
-drive file=virtio-win-0.1-74.iso,id=isocd -device ide-cd,bus=ide.2,drive=isocd \
-rtc base=localtime

Which works fine under Slackware -current with kernel 3.16.2... but doesn't under Arch.  There are two issues.  First, qemu doesn't execute, it terminates with an error about how "ide-hd" yes "h" not "c" previously being in use. Which is odd considering there is no ide-hd.

The line -drive file=/dev/sr0,id=cddisk -device ide-cd,bus=ide.1,drive=cddisk  is responsible, remove it and the problem goes away.  I can't find any permutation of -cdrom,  -device or -drive commands that allow sharing of the host cdrom drive.  Did I miss something new in qemu?  The version under slackware is 2.0.0.

The second problem is that Windows blue screens and can't boot, once I remove the offending cdrom line.  If I run the qemu script without passthrough (using vga-std) and without the cdrom line, then it boots fine.  Did something else change?

I also note that when I do boot successfully there are some console error messages about pulseaudio, presumably something I'm supposed to use under Arch and have not set up. (Slackware doesn't do pulseaudio, it's against our/their religion)

The hardware is an Nvidia Quadro K2000, the CPU intel 4960K, no intel graphics, vfio bind seems to have worked and there is the usual /dev/vfio/vfio and other files present.

Last edited by mostlyharmless (2015-01-22 21:18:02)

nythrix

Member

Registered: 2015-01-22

Posts: 4

Re: KVM VGA-Passthrough using the new vfio-vga support in kernel =>3.9

Thanks to the awesome people helping out in this thread I've been able to successfully pass through a 9600GT to a Windows 7 guest.

Unfortunately, linux guests don't work. I tried my oldish Debian VM, which has been running on "-vga std" since forever but I loose graphics output around the time the console switches fonts during boot (not sure how to describe it). Everything happens very quickly so the last messages I'm able to make out are stuff about intel RAPL and something about BARs ..? I wiped out the VM and reinstalled Debian but the problem persisted. The installation itself was flawless though (with passthrough). Twice.

Then I tried installing Fedora 21 Workstation. Couldn't get much further than some sort of greeting menu. It seems the signal is again lost during attempts to fiddle with the graphics/framebuffer.

Is this some sort of device reset problems I'm observing?

PS: I'm running 3.17 with the i915 arbiter patch. Qemu 2.1.2.