Re: [Xen-devel] PCI and VGA Passthrough regressions on Xen 4.4.1 vs 4.3.2

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Mon, Oct 06, 2014 at 03:55:36AM -0300, Zir Blazer wrote:
> There is a regression in both PCI and VGA Passthrough in Xen 4.4.1 when 
> compared to 4.3.2. Due to the added complexity of VGA Passthrough, I was 
> suggested to focus instead in my PCI Passthrough issue, which involves the 
> integrated Sound Card of my Motherboard. While it passes to the DomU and 
> works, it produces robotic, distorted and lagged noise everytime it 
> reproduces sound. The Video Card is an absolute no-go. On the previous Xen 
> version, everything else being equal, both works properly.I have been trying 
> to gather as much information as possible of my issue according to Xen Wiki 
> articles http://wiki.xen.org/wiki/Debugging_Xen and 
> http://wiki.xen.org/wiki/Reporting_Bugs_against_Xen so this E-Mail comes 
> attached with tons of logs.
> 
> 

Thank you for the detailed bug-report.

Interestingly enough I have been using the same exact hardware, thought

> HARDWARE
> Processor: Intel Xeon E3-1245V3 (Haswell) - 
> http://ark.intel.com/products/75462/Intel-Xeon-Processor-E3-1245-v3-8M-Cache-3_40-GHz

I seem to see 8 CPUs while your serial output say it has 4?

Did you disable hyper-threading?

> Motherboard: Supermicro X10SAT (Chipset C226, BIOS R2.0) - 
> http://www.supermicro.com/products/motherboard/Xeon/C220/X10SAT.cfm
> Sound Card: Integrated Realtek ALC1150
> Video Card: Haswell IGP, and a Radeon 5770 (Which is the GPU I always pass)

Anyhow, could you when booting under Xen 4.3 (and Xen 4.4) also use
iommu=verbose,debug

You should get something like this:

XEN) Enabling APIC mode:  Flat.  Using 1 I/O APICs
(XEN) ACPI: HPET id: 0x8086a701 base: 0xfed00000
(XEN) [VT-D]dmar.c:778: Host address width 39
(XEN) [VT-D]dmar.c:792: found ACPI_DMAR_DRHD:
(XEN) [VT-D]dmar.c:472:   dmaru->address = fed90000
(XEN) [VT-D]iommu.c:1158: drhd->address = fed90000 iommu->reg = ffff82c3ffd54000
(XEN) [VT-D]iommu.c:1160: cap = c0000020660462 ecap = f0101a
(XEN) [VT-D]dmar.c:383:  endpoint: 0000:00:02.0
(XEN) [VT-D]dmar.c:792: found ACPI_DMAR_DRHD:
(XEN) [VT-D]dmar.c:472:   dmaru->address = fed91000
(XEN) [VT-D]iommu.c:1158: drhd->address = fed91000 iommu->reg = ffff82c3ffd53000
(XEN) [VT-D]iommu.c:1160: cap = d2008c20660462 ecap = f010da
(XEN) [VT-D]dmar.c:397:  IOAPIC: 0000:f0:1f.0
(XEN) [VT-D]dmar.c:361:  MSI HPET: 0000:f0:0f.0
(XEN) [VT-D]dmar.c:486:   flags: INCLUDE_ALL
(XEN) [VT-D]dmar.c:797: found ACPI_DMAR_RMRR:
(XEN) [VT-D]dmar.c:383:  endpoint: 0000:00:1d.0
(XEN) [VT-D]dmar.c:383:  endpoint: 0000:00:1a.0
(XEN) [VT-D]dmar.c:383:  endpoint: 0000:00:14.0
(XEN) [VT-D]dmar.c:666:   RMRR region: base_addr d9eab000 end_address d9eb9fff
(XEN) [VT-D]dmar.c:797: found ACPI_DMAR_RMRR:
(XEN) [VT-D]dmar.c:383:  endpoint: 0000:00:02.0
(XEN) [VT-D]dmar.c:666:   RMRR region: base_addr dc000000 end_address de1fffff
(XEN) Xen ERST support is initialized.

And I only do PCI passthrough of NICs (which has been working fine
for me in Xen 4.3 - hadn't yet attempted Xen 4.4).

> September 2014: Xen 4.3.2, BIOS/UEFI Boot with Syslinux/Gummiboot, Arch Linux 
> ISO dated Oct 2014, Linux Kernel 3.16 with default config options or custom 
> 3.17 RC4
> Both Sound Card and Video Card works, including using my previous DomU, in 
> either BIOS mode with either Kernel or UEFI with 3.17. The minimal DomU works 
> as expected with only the Sound Card. The only shortcoming I found running 
> UEFI, is that using "reboot" command in console, sometimes freezes in the 
> last line when it says it is ready to reboot, other times it does work. Seems 
> prone to freeze when I just turned it on and want to reboot, but can reboot 
> consistently on prolonged sessions.
> 
> September 2014: Xen 4.4.1, BIOS/UEFI Boot with Syslinux/Gummiboot, Arch Linux 
> ISO dated Oct 2014, Linux Kernel 3.16 with default config options or custom 
> 3.17 RC4
> Sound Card passthrough to the minimal DomU (Which I created for testing 
> passthrough in 4.4.1, before I downgraded to 4.3.2 to test again) does not 
> work, robotic noise and interference as described. VGA Passthrough is a total 
> no-go, but I suppose than fixing whatever regression annoys the Sound Card 
> will fix the Video Card too. After tons of testing with different things 
> (BIOS or UEFI, Compiler flags, Kernel version, Kernel config), I conclude 
> that this is broken at least for my setup, as not even once I made it work.

Gotcha. And there were no BIOS updates in between using Xen 4.3 or Xen 4.4? I 
recall that BIOS v1.0 on those
boards would spit errors.

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