Re: KVM devices assignment; PCIe AER?

Michael S. Tsirkin
2010-10-26T18:44:16Z

On Tue, Oct 26, 2010 at 09:41:12AM -0700, etmartin101 wrote:
> Chris, Michael et al.
>
> Part of the project I'm working on, we are looking at extending the
> device assignment capabilities to provide support for PCIe AER.
> Ideally, the host would register for AER (for every assigned
> devices) and pass them up to Qemu.
>
> As of now, one of the problem is that KVM is not a driver for the
> assigned devices. I've seen Chris's slides from KVM conf 2010 but I
> haven't seen any patches or discussion on that topic...
>
> On another front, I've seen the work from Michael around 'uio_pci_generic'
> and some of his comments:
> " It's expected that more features of interest to virtualization will be
> added to this driver in the future. Possibilities are: mmap for device
> resources, MSI/MSI-X, eventfd (to interface with kvm), iommu."
>
> I think that extending 'uio_pci_generic' to support AER is
> relatively straight forward (assuming eventfd support from UIO).
>
> Any thought?
>
> thanks,
> -Etienne

On the qemu side, patches for aer support are being worked on,
pls take a look, likely there's some synergy there.

On the kernel side, AER for uio sounds fine, but the features listed
above are not yet supported, so you'd have to code them up too.
There's a uiommu driver from Tom Lyon that does the iommu bit.

Alex and Tom have been working on a VFIO driver which is not based on
the uio framework. You can try joining forces.

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