Re: PCI passthrough problems after legacy update of xen 4.1

[Gordan Bobic <gordan@bobich.net>]

Bad news, I'm afraid - I still get error "22, invalid argument" with 
this patch.

Gordan

On 05/14/2013 03:01 PM, Jan Beulich wrote:
>>>> On 05.05.13 at 21:33, Andreas Falck <falck.andreas.lists@gmail.com> wrote:
>> I tried adding some debugging statements in physdev_map_pirq. I have
>> attached the physdev.c with my debug statements, a hypervisor log from
>> testing, and the output of lspci -vv for my three devices.
>
> Since I didn't hear anything from either of you anymore, I went
> through the (not very familiar to me) tool stack code again, and
> found that qemu and xend/libxl fundamentally disagree about the
> model to be used. Qemu wants to allocate PIRQs while xend/libxl
> want a 1:1 mapping. Allocating after having created a 1:1 mapping
> works by returning the 1:1 mapping as allocation result, so as long
> as libxl completes its setup before launching qemu, it would be
> obvious why things work there. Consequently I assume that xend
> launches qemu quite a bit earlier in the process of creating a new
> domain, and the result of an attempt to establish a 1:1 mapping
> when a different mapping was already established is dependent on
> the specific interrupt numbers (i.e. also explains the observations
> one of you made).
>
> Since the tool stack as a whole really ought to use a consistent
> model, and since the 1:1 mapping model for non-MSI IRQs seems
> quite natural, the below/attached patch takes care of enforcing
> a 1:1 mapping in libxc when allocation is being requested by the
> caller. Ian, Ian - do you foresee any problem with this?
>
> Please both of you give this a try and let us know of the results
> (patch applies cleanly to all of -unstable, 4.2, and 4.1).
>
> Jan
>
> --- a/tools/libxc/xc_physdev.c
> +++ b/tools/libxc/xc_physdev.c
> @@ -49,7 +49,7 @@ int xc_physdev_map_pirq(xc_interface *xc
>       map.domid = domid;
>       map.type = MAP_PIRQ_TYPE_GSI;
>       map.index = index;
> -    map.pirq = *pirq;
> +    map.pirq = *pirq < 0 ? index : *pirq;
>
>       rc = do_physdev_op(xch, PHYSDEVOP_map_pirq, &map, sizeof(map));
>
> --- a/tools/python/xen/xend/server/pciif.py
> +++ b/tools/python/xen/xend/server/pciif.py
> @@ -340,7 +340,7 @@ class PciController(DevController):
>                   raise VmError(('pci: failed to configure I/O memory on device '+
>                               '%s - errno=%d')%(dev.name,rc))
>
> -        if not self.vm.info.is_hvm() and dev.irq:
> +        if dev.irq > 0:
>               rc = xc.physdev_map_pirq(domid = fe_domid,
>                                      index = dev.irq,
>                                      pirq  = dev.irq)
>
>