IOMMU support for xen in BIOS of AMD based HP DL385g7 and kernel 3.0.0-rc7

["M. Schneider" <ms@it-infrastrukturen.com>]

Hello Jörg,

Please allow me one question about IOMMU support in AMDS's 890FX chipset 
and 6176SE CPUs used in HP DL385g7 servers. These chips support IOMMU as 
far as I know. BIOS of HP DL385g7 doesn't currently offer an IOMMU flag.

I have contacted already HP support due to this missing BIOS setting 
options but less or more my request has been ignored (no solution and no 
plans for solving of this important issue  yet) so I am looking for a 
workaround as IOMMU support is required for passing thoruhg of PCI 
devices to domU domains (xen 4.0 / 4.1).

I have created xen debian live binary-hybrid iso images with kernel 
2.6.39-2 and 3.0.0-rc7 (aufs patch) for easy testing (inside the linke 
below there is information where you can download these images).
http://www.it-infrastrukturen.com/fileadmin/linux/debian-live-xen/README.xen

In the kernel 3.0.0-rc7 of 
xen41-wheezy-kernel3-amd64-live-gnome-binary-hybrid.iso I have enalbed 
IOMMU-debugging (s. the link to the image below)
rsync -avP 
rsync://www.it-infrastrukturen.ch/ftp/xen41-wheezy-kernel3-amd64-live-gnome-binary-hybrid.iso 
.

In the boot log are messages as follows:
# ---

(XEN) Enabling APIC mode:  Phys.  Using 2 I/O APICs
(XEN) ERST table is invalid
(XEN) Using scheduler: SMP Credit Scheduler (credit)
(XEN) Detected 2300.118 MHz processor.
(XEN) Initing memory sharing.
(XEN) AMD-Vi: IOMMU not found!
(XEN) I/O virtualisation disabled
(XEN) ENABLING IO-APIC IRQs
(XEN)  ->  Using new ACK method
(XEN) Platform timer is 14.318MHz HPET
(XEN) Allocated console ring of 64 KiB.
(XEN) HVM: ASIDs enabled.
(XEN) SVM: Supported advanced features:
(XEN)  - Nested Page Tables (NPT)
(XEN)  - Last Branch Record (LBR) Virtualisation
(XEN)  - Next-RIP Saved on #VMEXIT
(XEN)  - Pause-Intercept Filter
(XEN) HVM: SVM enabled
(XEN) HVM: Hardware Assisted Paging detected.
(XEN) Brought up 24 CPUs
(XEN) Xenoprofile: AMD IBS detected (0x0000001f)
(XEN) *** LOADING DOMAIN 0 ***
(XEN)  Xen  kernel: 64-bit, lsb, compat32
(XEN)  Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 ->  0x1937000
(XEN) PHYSICAL MEMORY ARRANGEMENT:
(XEN)  Dom0 alloc.:   000000023c000000->000000023e000000 (376344 pages to be allocated)
(XEN)  Init. ramdisk: 000000043dc18000->000000043fdff600

# ---

There is no log entry for an IVRS table (thank you to Wei Wang at AMD 
for his kind hints)

Please take a lok at full log files if you need more details:
http://www.it-infrastrukturen.com/fileadmin/linux/paste/xm_dmesg.xen41_on_DL385g7_NOK.txt
http://www.it-infrastrukturen.com/fileadmin/linux/paste/dmesg.xen41_on_DL385g7_NOK.txt

Thank you in advance for any answer/hints

Best regards,
Mark Schneider

-- 
IT-Infrastrukturen Schneider

Wieslergasse 6
CH-8049 Zürich

Phone:  +41 43 818 4508
Mobile: +41 76 522 2923

ms@it-infrastrukturen.com
http://www.it-infrastrukturen.com