Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[George Dunlap]

> On 2016-09-09 09:51, Peter Milesson wrote:
[snip]
>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>> upgrading regularly, and installed 4.7.0 today.
>>
>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>> need graphics pass through)
>>
>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>> shorter lines, a bit like thin coarse snow, when watching videos. The
>> distortions stayed within the movie, and was tolerable.
>>
>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>> for example, I open cnn.com and move the mouse pointer up and down over the
>> photos, which creates a bunch of flickering lines over the display. The same
>> with moving content in Youtube for example. Or opening a Cygwin terminal
>> window and scrolling through a file. Terrible.
>>
>> Nothing else has changed, only the Xen version.

[snip]

On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
> Hi again,
>
> I've been playing around a bit more.
>
> It seems one of the problems is that I passed a couple of PCI-devices (USB
> controllers) to the VM, beside the graphics card.
>
> When I pass the USB-devices individually in the VM configuration file
> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
> problems seem to be more or less gone.

Jan / Andy,

Can you think of anything that's changed between 4.6 and 4.7 that
would cause the performance problems he's describing when both a video
card and a usb controller are passed through, but not when only the
video card is passed through?

Details on hardware / config / guest OS below.

 -George

>> *Hardware*
>> CPU: AMD FX-6100 (6-core)
>> Chipset: AMD 970A (has got a working IOMMU)
>> RAM: 16GB DDR3-1600MHz
>> Video: AMD Radeon HD6450
>>
>> *OS*
>> Linux Slackware 14.2 (latest)
>> Kernel: 4.4.19 long term stable
>>
>> *Xen*
>> Version: 4.7.0 (configure same as 4.6.3 and previous versions)
>>  ./configure --prefix=/usr --localstatedir=/var --sysconfdir=/etc
>> --libdir=/usr/lib64 --with-xenstored=oxenstored --disable-qemu-traditional
>> --disable-rombios --disable-stubdom
>> Xen dom0 boot entry (grub2):
>> menuentry "Xen 4.7.0 / Slackware 14.2 (kernel 4.4.19-dom0)" {
>>        set root=(hd0,1)
>>        multiboot /boot/xen-4.7.0.gz iommu=1 dom0_mem=2048M
>> dom0_max_vcpus=2 dom0_vcpus_pin console=vga cpufreq=xen:performance noreboot
>>        module /boot/vmlinuz-4.4.19-dom0 console=vga earlyprintk=xen
>> root=/dev/sda1 ro clocksource=xen xencons=off
>> }
>>
>> *Guest OS*
>> Windows 10 Pro 64-bit (2VCPUs)
>> Latest PV Drivers (8.2 series)
>> Graphics driver: Latest WHQL driver 15.201.1151.1008

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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Jan Beulich]

>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>  On 2016-09-09 09:51, Peter Milesson wrote:
> [snip]
>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>> upgrading regularly, and installed 4.7.0 today.
>>>
>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>> need graphics pass through)
>>>
>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>> distortions stayed within the movie, and was tolerable.
>>>
>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>> photos, which creates a bunch of flickering lines over the display. The same
>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>> window and scrolling through a file. Terrible.
>>>
>>> Nothing else has changed, only the Xen version.
> 
> [snip]
> 
> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>> Hi again,
>>
>> I've been playing around a bit more.
>>
>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>> controllers) to the VM, beside the graphics card.
>>
>> When I pass the USB-devices individually in the VM configuration file
>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>> problems seem to be more or less gone.
> 
> Jan / Andy,
> 
> Can you think of anything that's changed between 4.6 and 4.7 that
> would cause the performance problems he's describing when both a video
> card and a usb controller are passed through, but not when only the
> video card is passed through?

Not really, no. Peter - are there any indications of problems in
one or more of the logs (Xen, xl, qemu)? Did you try running a
debug build of all Xen components?

Jan


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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Andrew Cooper]

On 14/09/16 13:50, Jan Beulich wrote:
>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>  On 2016-09-09 09:51, Peter Milesson wrote:
>> [snip]
>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>> upgrading regularly, and installed 4.7.0 today.
>>>>
>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>>> need graphics pass through)
>>>>
>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>> distortions stayed within the movie, and was tolerable.
>>>>
>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>>> photos, which creates a bunch of flickering lines over the display. The same
>>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>>> window and scrolling through a file. Terrible.
>>>>
>>>> Nothing else has changed, only the Xen version.
>> [snip]
>>
>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>> Hi again,
>>>
>>> I've been playing around a bit more.
>>>
>>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>>> controllers) to the VM, beside the graphics card.
>>>
>>> When I pass the USB-devices individually in the VM configuration file
>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>> problems seem to be more or less gone.
>> Jan / Andy,
>>
>> Can you think of anything that's changed between 4.6 and 4.7 that
>> would cause the performance problems he's describing when both a video
>> card and a usb controller are passed through, but not when only the
>> video card is passed through?
> Not really, no. Peter - are there any indications of problems in
> one or more of the logs (Xen, xl, qemu)? Did you try running a
> debug build of all Xen components?

Furthermore, does "Nothing else has changed, only the Xen version." mean
switching your distro packages between two versions of xen, or literally
only switching the hypervisor itself.

A substantial quantity of the complexity here is in qemu, rather than Xen.

~Andrew

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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[George Dunlap]

On 14/09/16 14:23, Andrew Cooper wrote:
> On 14/09/16 13:50, Jan Beulich wrote:
>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>>  On 2016-09-09 09:51, Peter Milesson wrote:
>>> [snip]
>>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>>> upgrading regularly, and installed 4.7.0 today.
>>>>>
>>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>>>> need graphics pass through)
>>>>>
>>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>>> distortions stayed within the movie, and was tolerable.
>>>>>
>>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>>>> photos, which creates a bunch of flickering lines over the display. The same
>>>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>>>> window and scrolling through a file. Terrible.
>>>>>
>>>>> Nothing else has changed, only the Xen version.
>>> [snip]
>>>
>>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>>> Hi again,
>>>>
>>>> I've been playing around a bit more.
>>>>
>>>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>>>> controllers) to the VM, beside the graphics card.
>>>>
>>>> When I pass the USB-devices individually in the VM configuration file
>>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>>> problems seem to be more or less gone.
>>> Jan / Andy,
>>>
>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>> would cause the performance problems he's describing when both a video
>>> card and a usb controller are passed through, but not when only the
>>> video card is passed through?
>> Not really, no. Peter - are there any indications of problems in
>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>> debug build of all Xen components?
> 
> Furthermore, does "Nothing else has changed, only the Xen version." mean
> switching your distro packages between two versions of xen, or literally
> only switching the hypervisor itself.

I assume he's using "Xen" to mean the whole Xen system -- hypervisor +
tools + qemu.

> A substantial quantity of the complexity here is in qemu, rather than Xen.

Rather than the hypervisor, you mean.

Another thing worth asking, Peter: Have you tried running with
qemu-traditional (by adding the line below to your config file) rather
than qemu-upstream, to see if that makes a difference?

device_model_version="qemu-xen-traditional"

qemu-traditional almost ever changes, so if it worked better, then that
would point the finger at changes in qemu (at which point we would have
to bring in a different set of people to help diagnose it).

 -George

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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson]

On 2016-09-14 14:50, Jan Beulich wrote:
>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>   On 2016-09-09 09:51, Peter Milesson wrote:
>> [snip]
>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>> upgrading regularly, and installed 4.7.0 today.
>>>>
>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>>> need graphics pass through)
>>>>
>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>> distortions stayed within the movie, and was tolerable.
>>>>
>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>>> photos, which creates a bunch of flickering lines over the display. The same
>>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>>> window and scrolling through a file. Terrible.
>>>>
>>>> Nothing else has changed, only the Xen version.
>> [snip]
>>
>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>> Hi again,
>>>
>>> I've been playing around a bit more.
>>>
>>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>>> controllers) to the VM, beside the graphics card.
>>>
>>> When I pass the USB-devices individually in the VM configuration file
>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>> problems seem to be more or less gone.
>> Jan / Andy,
>>
>> Can you think of anything that's changed between 4.6 and 4.7 that
>> would cause the performance problems he's describing when both a video
>> card and a usb controller are passed through, but not when only the
>> video card is passed through?
> Not really, no. Peter - are there any indications of problems in
> one or more of the logs (Xen, xl, qemu)? Did you try running a
> debug build of all Xen components?
>
> Jan
>
Hi Jan,

No, I did not try a debug build. However, the system seems fairly stable 
now, only the display driver crashing once, or twice a day. That did 
occur with Xen 4.6.3 also, but maybe once a week. Looking at the log 
files, I cannot see anything particular that stands out, except for the 
domU log.

The domU log file qemu-dm-<Name>.log started to contain the following 
lines after upgrading to 4.7:

[00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU. 
@0x0000000000000004
[00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU. 
@0x0000000000000000

There are only a couple of lines with write, the rest with read. I don't 
know what significance it's got, but there are around 350 lines every day.

Thanks a lot for your interest and good work.

Regards,

Peter




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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson]

On 2016-09-14 15:23, Andrew Cooper wrote:
> On 14/09/16 13:50, Jan Beulich wrote:
>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>>   On 2016-09-09 09:51, Peter Milesson wrote:
>>> [snip]
>>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>>> upgrading regularly, and installed 4.7.0 today.
>>>>>
>>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>>>> need graphics pass through)
>>>>>
>>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>>> distortions stayed within the movie, and was tolerable.
>>>>>
>>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>>>> photos, which creates a bunch of flickering lines over the display. The same
>>>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>>>> window and scrolling through a file. Terrible.
>>>>>
>>>>> Nothing else has changed, only the Xen version.
>>> [snip]
>>>
>>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>>> Hi again,
>>>>
>>>> I've been playing around a bit more.
>>>>
>>>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>>>> controllers) to the VM, beside the graphics card.
>>>>
>>>> When I pass the USB-devices individually in the VM configuration file
>>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>>> problems seem to be more or less gone.
>>> Jan / Andy,
>>>
>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>> would cause the performance problems he's describing when both a video
>>> card and a usb controller are passed through, but not when only the
>>> video card is passed through?
>> Not really, no. Peter - are there any indications of problems in
>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>> debug build of all Xen components?
> Furthermore, does "Nothing else has changed, only the Xen version." mean
> switching your distro packages between two versions of xen, or literally
> only switching the hypervisor itself.
>
> A substantial quantity of the complexity here is in qemu, rather than Xen.
>
> ~Andrew
Hi Andrew,

I previously compiled and run Xen 4.6.3 in the same environment. Without 
making any changes to anything else, then downloading, compiling and 
installing Xen 4.7.0.

But read my following 2 posts. I stopped passing the original USB 
controller (2 PCI devices), and switched to another USB controller. All 
the previous problems completely gone. Logically, it doesn't make sense, 
because passing those 2 PCI devices, or these 2, should be completely 
irrelevant.

Best regards,

Peter


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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[George Dunlap]

On Wed, Sep 14, 2016 at 3:04 PM, Peter Milesson <miles@atmos.eu> wrote:
>
>
> On 2016-09-14 14:50, Jan Beulich wrote:
>>>>>
>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>>
>>>>   On 2016-09-09 09:51, Peter Milesson wrote:
>>>
>>> [snip]
>>>>>
>>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>>> upgrading regularly, and installed 4.7.0 today.
>>>>>
>>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't
>>>>> seem to
>>>>> need graphics pass through)
>>>>>
>>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>>> distortions stayed within the movie, and was tolerable.
>>>>>
>>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly.
>>>>> Just
>>>>> for example, I open cnn.com and move the mouse pointer up and down over
>>>>> the
>>>>> photos, which creates a bunch of flickering lines over the display. The
>>>>> same
>>>>> with moving content in Youtube for example. Or opening a Cygwin
>>>>> terminal
>>>>> window and scrolling through a file. Terrible.
>>>>>
>>>>> Nothing else has changed, only the Xen version.
>>>
>>> [snip]
>>>
>>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>>>
>>>> Hi again,
>>>>
>>>> I've been playing around a bit more.
>>>>
>>>> It seems one of the problems is that I passed a couple of PCI-devices
>>>> (USB
>>>> controllers) to the VM, beside the graphics card.
>>>>
>>>> When I pass the USB-devices individually in the VM configuration file
>>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>>> problems seem to be more or less gone.
>>>
>>> Jan / Andy,
>>>
>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>> would cause the performance problems he's describing when both a video
>>> card and a usb controller are passed through, but not when only the
>>> video card is passed through?
>>
>> Not really, no. Peter - are there any indications of problems in
>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>> debug build of all Xen components?
>>
>> Jan
>>
> Hi Jan,
>
> No, I did not try a debug build. However, the system seems fairly stable
> now, only the display driver crashing once, or twice a day. That did occur
> with Xen 4.6.3 also, but maybe once a week.

Well crashing twice a day isn't what most people would call "stable".
:-)  In any case, I was trying to debug the issue you had with passing
through both the video card and the usb controller -- that is
obviously an important configuration, but if there's a bug in that
configuration it probably affects a large number of wider
configurations as well.

> Looking at the log files, I
> cannot see anything particular that stands out, except for the domU log.
>
> The domU log file qemu-dm-<Name>.log started to contain the following lines
> after upgrading to 4.7:
>
> [00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU.
> @0x0000000000000004
> [00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU.
> @0x0000000000000000
>
> There are only a couple of lines with write, the rest with read. I don't
> know what significance it's got, but there are around 350 lines every day.

Yeah, those definitely look important.  This is with just the video
card passed through, or with both passed through?

 -George

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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson]

On 2016-09-14 15:30, George Dunlap wrote:
> On 14/09/16 14:23, Andrew Cooper wrote:
>> On 14/09/16 13:50, Jan Beulich wrote:
>>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>>>   On 2016-09-09 09:51, Peter Milesson wrote:
>>>> [snip]
>>>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>>>> upgrading regularly, and installed 4.7.0 today.
>>>>>>
>>>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't seem to
>>>>>> need graphics pass through)
>>>>>>
>>>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>>>> distortions stayed within the movie, and was tolerable.
>>>>>>
>>>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly. Just
>>>>>> for example, I open cnn.com and move the mouse pointer up and down over the
>>>>>> photos, which creates a bunch of flickering lines over the display. The same
>>>>>> with moving content in Youtube for example. Or opening a Cygwin terminal
>>>>>> window and scrolling through a file. Terrible.
>>>>>>
>>>>>> Nothing else has changed, only the Xen version.
>>>> [snip]
>>>>
>>>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>>>> Hi again,
>>>>>
>>>>> I've been playing around a bit more.
>>>>>
>>>>> It seems one of the problems is that I passed a couple of PCI-devices (USB
>>>>> controllers) to the VM, beside the graphics card.
>>>>>
>>>>> When I pass the USB-devices individually in the VM configuration file
>>>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>>>> problems seem to be more or less gone.
>>>> Jan / Andy,
>>>>
>>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>>> would cause the performance problems he's describing when both a video
>>>> card and a usb controller are passed through, but not when only the
>>>> video card is passed through?
>>> Not really, no. Peter - are there any indications of problems in
>>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>>> debug build of all Xen components?
>> Furthermore, does "Nothing else has changed, only the Xen version." mean
>> switching your distro packages between two versions of xen, or literally
>> only switching the hypervisor itself.
> I assume he's using "Xen" to mean the whole Xen system -- hypervisor +
> tools + qemu.
>
>> A substantial quantity of the complexity here is in qemu, rather than Xen.
> Rather than the hypervisor, you mean.
>
> Another thing worth asking, Peter: Have you tried running with
> qemu-traditional (by adding the line below to your config file) rather
> than qemu-upstream, to see if that makes a difference?
>
> device_model_version="qemu-xen-traditional"
>
> qemu-traditional almost ever changes, so if it worked better, then that
> would point the finger at changes in qemu (at which point we would have
> to bring in a different set of people to help diagnose it).
>
>   -George
Hi George,

I have always been using the default. I never had the need to set a 
specific device model. So it's qemu-upstream in my case.

Best regards,

Peter



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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson]

On 2016-09-14 16:17, George Dunlap wrote:
> On Wed, Sep 14, 2016 at 3:04 PM, Peter Milesson <miles@atmos.eu> wrote:
>>
>> On 2016-09-14 14:50, Jan Beulich wrote:
>>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>>>    On 2016-09-09 09:51, Peter Milesson wrote:
>>>> [snip]
>>>>>> I've been using Xen for 3 years, starting out with 4.2, and I've been
>>>>>> upgrading regularly, and installed 4.7.0 today.
>>>>>>
>>>>>> I'm using Windows 10, 64-bit with PCI pass through in a VM with
>>>>>> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't
>>>>>> seem to
>>>>>> need graphics pass through)
>>>>>>
>>>>>> Previously (up till Xen 4.6.3), the graphics output has displayed some
>>>>>> shorter lines, a bit like thin coarse snow, when watching videos. The
>>>>>> distortions stayed within the movie, and was tolerable.
>>>>>>
>>>>>> After upgrade to Xen 4.7.0, the video performance is seriously ugly.
>>>>>> Just
>>>>>> for example, I open cnn.com and move the mouse pointer up and down over
>>>>>> the
>>>>>> photos, which creates a bunch of flickering lines over the display. The
>>>>>> same
>>>>>> with moving content in Youtube for example. Or opening a Cygwin
>>>>>> terminal
>>>>>> window and scrolling through a file. Terrible.
>>>>>>
>>>>>> Nothing else has changed, only the Xen version.
>>>> [snip]
>>>>
>>>> On Fri, Sep 9, 2016 at 10:35 AM, Peter Milesson <miles@atmos.eu> wrote:
>>>>> Hi again,
>>>>>
>>>>> I've been playing around a bit more.
>>>>>
>>>>> It seems one of the problems is that I passed a couple of PCI-devices
>>>>> (USB
>>>>> controllers) to the VM, beside the graphics card.
>>>>>
>>>>> When I pass the USB-devices individually in the VM configuration file
>>>>> (usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display
>>>>> problems seem to be more or less gone.
>>>> Jan / Andy,
>>>>
>>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>>> would cause the performance problems he's describing when both a video
>>>> card and a usb controller are passed through, but not when only the
>>>> video card is passed through?
>>> Not really, no. Peter - are there any indications of problems in
>>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>>> debug build of all Xen components?
>>>
>>> Jan
>>>
>> Hi Jan,
>>
>> No, I did not try a debug build. However, the system seems fairly stable
>> now, only the display driver crashing once, or twice a day. That did occur
>> with Xen 4.6.3 also, but maybe once a week.
> Well crashing twice a day isn't what most people would call "stable".
> :-)  In any case, I was trying to debug the issue you had with passing
> through both the video card and the usb controller -- that is
> obviously an important configuration, but if there's a bug in that
> configuration it probably affects a large number of wider
> configurations as well.
>
>> Looking at the log files, I
>> cannot see anything particular that stands out, except for the domU log.
>>
>> The domU log file qemu-dm-<Name>.log started to contain the following lines
>> after upgrading to 4.7:
>>
>> [00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU.
>> @0x0000000000000004
>> [00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU.
>> @0x0000000000000000
>>
>> There are only a couple of lines with write, the rest with read. I don't
>> know what significance it's got, but there are around 350 lines every day.
> Yeah, those definitely look important.  This is with just the video
> card passed through, or with both passed through?
>
>   -George
Hi George,

This is with both the USB controller, and the graphics card.

Best regards,

Peter


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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Jan Beulich]

>>> On 14.09.16 at 16:04, <miles@atmos.eu> wrote:
> On 2016-09-14 14:50, Jan Beulich wrote:
>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>> would cause the performance problems he's describing when both a video
>>> card and a usb controller are passed through, but not when only the
>>> video card is passed through?
>> Not really, no. Peter - are there any indications of problems in
>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>> debug build of all Xen components?
> 
> No, I did not try a debug build. However, the system seems fairly stable 
> now, only the display driver crashing once, or twice a day. That did 
> occur with Xen 4.6.3 also, but maybe once a week. Looking at the log 
> files, I cannot see anything particular that stands out, except for the 
> domU log.
> 
> The domU log file qemu-dm-<Name>.log started to contain the following 
> lines after upgrading to 4.7:
> 
> [00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU. 
> @0x0000000000000004
> [00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU. 
> @0x0000000000000000
> 
> There are only a couple of lines with write, the rest with read. I don't 
> know what significance it's got, but there are around 350 lines every day.

Looks wrong in any case, but I have no clue whether it's indicative
of the problem you're having. In any event in the qemu tree in
hw/xen/xen_pt.h there's an "#ifdef XEN_PT_LOGGING_ENABLED"
conditional close to the top. Could you make this "#if 1" instead
(or simply #define XEN_PT_LOGGING_ENABLED in the line above)
and re-build at least qemu? The log of a subsequent guest run
should then be quite a bit more helpful in possibly spotting what's
going wrong to cause those messages.

And then it's of course rather relevant to know what device 00:06.0
actually is (iirc these are guest BDF values), considering that you're
passing through more than one.

Jan



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Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson]

On 2016-09-14 16:49, Jan Beulich wrote:
>>>> On 14.09.16 at 16:04, <miles@atmos.eu> wrote:
>> On 2016-09-14 14:50, Jan Beulich wrote:
>>>>>> On 14.09.16 at 13:34, <george.dunlap@citrix.com> wrote:
>>>> Can you think of anything that's changed between 4.6 and 4.7 that
>>>> would cause the performance problems he's describing when both a video
>>>> card and a usb controller are passed through, but not when only the
>>>> video card is passed through?
>>> Not really, no. Peter - are there any indications of problems in
>>> one or more of the logs (Xen, xl, qemu)? Did you try running a
>>> debug build of all Xen components?
>> No, I did not try a debug build. However, the system seems fairly stable
>> now, only the display driver crashing once, or twice a day. That did
>> occur with Xen 4.6.3 also, but maybe once a week. Looking at the log
>> files, I cannot see anything particular that stands out, except for the
>> domU log.
>>
>> The domU log file qemu-dm-<Name>.log started to contain the following
>> lines after upgrading to 4.7:
>>
>> [00:06.0] xen_pt_bar_read: Error: Should not read BAR through QEMU.
>> @0x0000000000000004
>> [00:06.0] xen_pt_bar_write: Error: Should not write BAR through QEMU.
>> @0x0000000000000000
>>
>> There are only a couple of lines with write, the rest with read. I don't
>> know what significance it's got, but there are around 350 lines every day.
> Looks wrong in any case, but I have no clue whether it's indicative
> of the problem you're having. In any event in the qemu tree in
> hw/xen/xen_pt.h there's an "#ifdef XEN_PT_LOGGING_ENABLED"
> conditional close to the top. Could you make this "#if 1" instead
> (or simply #define XEN_PT_LOGGING_ENABLED in the line above)
> and re-build at least qemu? The log of a subsequent guest run
> should then be quite a bit more helpful in possibly spotting what's
> going wrong to cause those messages.
>
> And then it's of course rather relevant to know what device 00:06.0
> actually is (iirc these are guest BDF values), considering that you're
> passing through more than one.
>
> Jan
>
>
Hi Jan,

I had a look at the guest devices, and Windows says "Standard Enhanced 
PCI to USB Host Controller". Having a look at the Properties, in the 
Device status field is the following message:
---
This device cannot start. (Code 10)

{Operation Failed}
The requested operation was unsuccessful.
---

This USB device wasn't there with Xen 4.6.3. Has it got something to do 
with the new USB passthrough? However, I have tried USB passthrough (xl 
usbctrl-attach), which doesn't work. But that is possibly another problem.

No problem to recompile Xen with the logging flag, if it would be required.

Best regards,

Peter

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