[Xen-users] MSI 890FXA-GD70 "BIOS bug" causes IOMMU + AMD VIrtualization errors in Xen 4.4.x

["XORr0@xxxxxxxxxx" <XORr0@xxxxxxxxxx>]

I have an MSI 890FXA-GD70 motherboard, and have been attempting (so far, completely unsuccessfully) to get VGA Passthrough working with Xen 4.4.2 (using EITHER primary or secondary AMD HD6970 video card). I believe the show stopper for me is these errors I receive according to 'xl dmesg' output on my Fedora 20 x86_64 dom0 system:

(XEN) IVHD Error: no information for IO-APIC 0x2
(XEN) AMD-Vi: Error initialization
(XEN) I/O virtualisation disabled

- I have attached additional debug output to this post (as filename: 'xen-4.4.2-dom0-xl_dmesg-output.txt'), which gives much more details, and context to these errors.

From seeing other people report similar error messages/issues on this (and xen-devel) mailing list(s), my understanding of the root issue is a "BIOS bug that builds a broken IVRS ACPI table". In turn, Xen recognizes this and disables I/O virtualization. I believe these errors stem from Xen Security Advisory #36 (XSA-36).
I've seen it reported that (I believe prior to XSA-36) my exact motherboard fully supported IOMMU and AMD-Virtualization + VGA Passthrough on a beta BIOS v1.75, on older Xen version(s).

My hope is to resolve these errors! My impression based on my research, is that the Xen developers + Xen community members believe the motherboard manufacturer should issue a BIOS update to correct the "broken IVRS ACPI table". I have opened a Support Ticket with MSI in the hopes of truly getting a fixed BIOS... but I faith is stretching thin at this point, as I've already made a posting to the official MSI Forums reporting the BIOS bug, but was told by the Forum Admin:

'''
board is EOL and don't think they can produce a new (BIOS) for it
but you can contact msi tech [...] to ask anyway
'''

I still have my fingers crossed hoping the MSI Support Ticket will bear fruit though, time will only tell.

I come now to the xen-users mailing list, #1 to notify others and report my issues, and #2 hoping some kind soul may point me in the direction to how I may solve this problem and ultimately get IOMMU and AMD-Virtualization enabled in lieu of an official BIOS update .

I have gone so far as to try issuing the check override suggested by the RESOLUTION section of XSA-36 by specifying "iommu=no-amd-iommu-perdev-intremap" via the Xen command line at boot time. Also I've tried "iommu=no-intremap", but each time I try either override option (with ANY version of BIOS = v1.D, beta v1.75, latest stable v1.15, and even latest beta v1.16B1) my system completely halts immediately after the Xen command-line boot screen with a flashing cursor in the top-left-hand corner on a blank/black background. I cannot get a successful boot no matter what combination I try using the check override suggested in XSA-36. I do get successful full boot-up issuing 'iommu=1', but IOMMU + AMD-Virtualization gets disabled with said errors.

I have seen others post of a way to patch Xen so that it will disable the check entirely (which I believe Xen developers consider wholly unsupported). If this is the only way for me to solve my issue, I would like to explore that possibility... I am not sure though, what patch(es) need implemented... I am running Qubes OS R3.0-rc1, with Fedora 20 x86_64 as dom0 operating system + Xen 4.4.2. The following are the exact versions of all the "Xen" packages included in the Fedora 20 x86_64 dom0 system:

[XORr0@dom0 ~]$ rpm -qa \*xen\*
xen-hypervisor-4.4.2-5.1.fc20.x86_64
libvirt-daemon-driver-xen-1.2.12-3.fc20.x86_64
xen-libs-4.4.2-5.1.fc20.x86_64
xen-4.4.2-5.1.fc20.x86_64
 [....]
xen-licenses-4.4.2-5.1.fc20.x86_64
xen-hvm-4.4.2gui3.0.0-5.1.fc20.x86_64
libvirt-daemon-xen-1.2.12-3.fc20.x86_64
xen-runtime-4.4.2-5.1.fc20.x86_64

If there is any solution that can be suggested, I am all ears! I am hoping there is a simple way to correct my problem, but if it requires rebuilding Xen myself, with patches, I will do the work to figure it out. I don't believe I have many options at this point, if ANY at all... Please help!

My hardware, software, and operating system setup is as follows:

MOTHERBOARD: MSI 890FXA-GD70, currently running latest beta BIOS version 1.16B1 (11-06-2012)
CPU: AMD Athlon II X2 270 Regor Dual-Core 3.4GHz Socket AM3
POWER SUPPLY: CORSAIR Professional Series Gold AX1200 - 1200W
MEMORY: 16GB total (4x 4GB sticks), G.SKILL Sniper 4GB DDR3 SDRAM DDR3 1600 (PC3 12800)
HARD DRIVES: 2x Seagate Barracuda Green ST1500DL003 1.5TB 5900 RPM
VIDEO CARDS: 2x XFX Radeon HD 6970 2GB 256-Bit GDDR5 PCI Express 2.1 x16
OPERATING SYSTEM: Qubes R3.0-rc1 x86_64
DOM0 OPERATING SYSTEM: Fedora 20 x86_64
XEN VERSION: Xen 4.4.2

I am attaching the output of multiple commands with debug info, run from the Fedora 20 x86_64 dom0 system to see if this provides more information/helps (anyone):

• xl info
• xl dmesg (booted with iommu=debug,verbose)
• dmesg
• lspci -vvv

I welcome anyone willing to assist.
If anyone would like more information, or needs additional details I am happy to oblige.

Attachment: dmesg-output.txt
Description: Text document

Attachment: lspci-vvv-output.txt
Description: Text document

Attachment: xen-4.4.2-dom0-xl_dmesg-output.txt
Description: Text document

Attachment: xl_info.txt
Description: Text document

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