Re: [Xen-devel] GPLPV and pci passthrough

[James Harper <james.harper@xxxxxxxxxxxxxxxx>]

> 
> James,
>       At least one other person (Lta, included in this message) and I have
> had problems using passthrough pci devices and your GPLPV drivers at the
> same time.  My symptoms are that SMB connections are totally unreliable
> (however, downloading over http seems to work well enough).
> For example, if I start a video or audio file, playing from the network, it 
> will
> play the first few seconds fine, then the connection drops out.
> I can confirm that the problems don't exist when not passing through any
> devices.
> 
>       I'm using xen-unstable c/s 24465, 3.2.1 dom0, win 7 64bit domU with
> an ATI 4770, USB controller, and ICE1712 based pci sound card passed
> through.  I used the gplpv_Vista2008x64_0.11.0.308.msi drivers.
> 
>       I tried the -debug drivers, and I see a ton of output in qemu log,
> however, all that output seems to be at initialization.  I do not see any
> additional output from your drivers after boot, including when I'm
> experiencing problems.
> 
>       I took a quick look at tcpdump output and it does seem the guest is
> ACKing the packets as they come in, so my first guess is that they're getting
> lost somewhere between the driver and the OS network stack.
> 
>       I've never set up a build environment for these drivers so I haven't
> tried adding any extra debug output.  Have you looked into the (or a similar)
> problem before, or have a more verbose debug copy of the net driver you've
> used to diagnose similar problems before?
> 
>       I guess the real question is, do you have any idea where we should
> start looking?
> 

I'd be first looking at interrupt sharing. Maybe GPLPV doesn't like sharing 
interrupts with anything?

Have a look in device manager and set the view as "Resources by type" and see 
if anything is sharing an interrupt with the "Xen PCI Device Driver".

James

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