Re: [Xen-devel] Debugging passthrough on an S3210SHLC

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

On Sat, Mar 16, 2013 at 04:05:19PM +0000, Peter Kay wrote:
> On 15 March 2013 21:02, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
> > 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?
> Yes, and I've passed hardware through in Esxi 5.1. It's a server
> chipset with IOMMU, but pre Nehalem so the features are less complete.

Oh. I didn't know that such mutants existed :-)
> 
> >
> >> 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?
> >
> Yes. I'm given to understand the passthrough parameter should maintain
> the BDF - but it doesn't, and there appears to be no advice on this on
> the Internet other than 'it should work' (but doesn't for some
> people).

That depends. The xen-pciback.vpci argument that define whether you
want them to be virtual (so they start at 00) or match your host.

But that option is only usefull for PV guests. I think you are using
an HVM one. In which that does not matter that much I would think.

> 
> >> 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?
> 
> I don't know - that's why I'm asking :). I don't mind doing a bit of
> debug work but I'm getting a little tired of trying kernels just in
> case it might work.

I just used the distro's default and also the distro's default Xen.
Fedora 17 or Fedora 18.
> 
> >>
> >> 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?
> 
> No, you're thinking of the 3C509. The 3C900 is an old PCI 10Mb NIC. It
> may be this is far too old and I need to try something newer (it was
> only as a test and was to hand).
> 
> >> 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:
> 
> Can I ask which kernel you are using, please?

Stock Fedora. Thought right now I rebuilt it with v3.9-rc2 with an Fedora 
config.

> 
> > 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.
> 
> Thanks!

> 
> PK

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