Re: [Xen-devel] Broken PCI device passthrough, after XSA-302 fix?

[Pasi Kärkkäinen <pasik@xxxxxx>]

Hi,

On Mon, Jan 06, 2020 at 02:06:14PM +0100, Jan Beulich wrote:
> On 04.01.2020 02:07, Marek Marczykowski-Górecki  wrote:
> > I have a multi-function PCI device, behind a PCI bridge, that normally
> > I assign to a single domain. But now it fails with:
> > 
> > (XEN) [VT-D]d14: 0000:04:00.0 owned by d0!<G><0>assign 0000:05:00.0 to 
> > dom14 failed (-22)
> 
> I've tried this out in as close a setup as I could arrange for, but
> not one matching your scenario. I didn't find a system with a
> suitably placed (in the topology) multi-function device (had to use
> a single-function one), and of course I did this on (close to)
> master. No anomalies. Hence I wonder whether either of the two
> differences mentioned matters, and - if, as I suspect, it's the
> multi-function aspect that is relevant here - how things would have
> worked at all before those recent changes. This is because I think
> you should have hit the same error path even before, and it would
> seem to me that the patch below might be (and have been) needed.
> 

I think Marek confirmed in the other mail that this patch fixes the issue.

Are you planning to merge this patch?


Thanks,

-- Pasi

> Jan
> 
> --- unstable.orig/xen/drivers/passthrough/vtd/iommu.c
> +++ unstable/xen/drivers/passthrough/vtd/iommu.c
> @@ -1505,7 +1505,7 @@ static int domain_context_mapping(struct
>              break;
>  
>          ret = domain_context_mapping_one(domain, drhd->iommu, bus, devfn,
> -                                         pci_get_pdev(seg, bus, devfn));
> +                                         NULL);
>  
>          /*
>           * Devices behind PCIe-to-PCI/PCIx bridge may generate different
> @@ -1515,7 +1515,7 @@ static int domain_context_mapping(struct
>          if ( !ret && pdev_type(seg, bus, devfn) == DEV_TYPE_PCIe2PCI_BRIDGE 
> &&
>               (secbus != pdev->bus || pdev->devfn != 0) )
>              ret = domain_context_mapping_one(domain, drhd->iommu, secbus, 0,
> -                                             pci_get_pdev(seg, secbus, 0));
> +                                             NULL);
>  
>          break;
>  
> 
> 

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