Re: Debugging passthrough on an S3210SHLC

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Mar 01, 2013 at 02:00:08PM +0000, Peter Kay wrote:
> I'm having difficulty getting any passthrough working on an S3210SHLC (X38 derived S3210 socket 775 server chipset, thus pre SLAT) - this is on the list of supported hardware. Is there any guide as to what can be done - I've tried iommu=verbose, so is the next step sending debug printfs to the xen console? I realise this is a development list so I'd like advice on which bits of source to poke so I can find the root issue.
> 

This hardware has actual IOMMU?

> The hardware does work - I've passed the embedded G200e through using ESXi 5.1 although other devices (a Radeon 6950) don't work.
> 
> Issues are - both with XCP1.6 and xen 4.2 (with some small AMD VGA passthrough patches)/xen 4.3 unstable on Debian Wheezy :
> 
> Pciback is a module. It recognises the passthrough keyword but PCI IDs are still modified in VMs.


Not sure what you mean by that. Modified in VMs? You mean that the BDF value is different?

> 
> Pt_iomul errors in qemu log even though the status is 'successful'
> 
> Xl create errors out with a gnttab error both in 4.2/4.3. Xm works.

Uh, that is not good. Why would 'xl' die on that? Is that fixed with a different
version of the Linux kernel?

> 
> When passing through an old 3C900 PCI NIC as a test, this causes noise in the audigy 4 PCI soundcard in the next slot unless that is also passed through. I suspect this is due to the bus layout of the S3210SHLC. Is it always necessary to pass all PCI devices on the same root through? Also should it be necessary/possible to pass a PCI root?
> 

Isn't that an ISA card? Do you mean 3c590 perhaps?

> The VMs think the device was successfully passed through (a wheezy hvm binds the appropriate modules and a Windows 7 hvm has seen the radeon) but they don't actually work.
> 
> There are so many combinations of hardware and kernel finding out what is wrong is tricky. I'd appreciate some advice diagnosing it.

So I've been quite successfull with both AMD and Intel to pass in a PCIe type NIC. And also
an Radeon card in Windows 7:

04:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
06:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RV770 [Radeon HD 4870]
06:00.1 Audio device: Advanced Micro Devices [AMD] nee ATI RV770 HDMI Audio [Radeon HD 4850/4870]

Without any modifications to Xen. Just used Fedora 18 and use xen-pciback.hide to hide
the 04:00.0 and 06:00.* and passed them in to the guest:

builder='hvm'
memory = 2048
name = "Windows7"
vcpus=3
disk = [ 'phy:/dev/vg_guest/Win7_Home,hda,w']
vnc=1
videoram=8
vnclisten="0.0.0.0"
vncpasswd=''
stdvga=0
serial='pty'
tsc_mode=0
usb=1
usb_add="host:045e:0040"
usbdevice='tablet'
xen_platform_pci=1
# Remember QEMU_AUDIO_DRV=pa
soundhw='es1370'
pci=['04:00.0','06:00.1','06:00.0']

> 
> Hardware is S3210SHLC with latest (52) BIOS, embedded Matrox G200e, two E1000s of some type, a GeForce G210 (for console), Reference AMD 6950 (on the PCH 4x slot as MCH slot bandwidths are restricted for graphics cards), audigy 4 PCI and 3C900.
> 
> Cheers!

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