[PATCH RFC 00/22] EEH Support for VFIO PCI devices on PowerKVM guest
Alex Williamson
alex.williamson at redhat.com
Tue May 6 00:00:12 EST 2014
On Mon, 2014-05-05 at 13:56 +0200, Alexander Graf wrote:
> On 05/05/2014 03:27 AM, Gavin Shan wrote:
> > The series of patches intends to support EEH for PCI devices, which have been
> > passed through to PowerKVM based guest via VFIO. The implementation is
> > straightforward based on the issues or problems we have to resolve to support
> > EEH for PowerKVM based guest.
> >
> > - Emulation for EEH RTAS requests. Thanksfully, we already have infrastructure
> > to emulate XICS. Without introducing new mechanism, we just extend that
> > existing infrastructure to support EEH RTAS emulation. EEH RTAS requests
> > initiated from guest are posted to host where the requests get handled or
> > delivered to underly firmware for further handling. For that, the host kerenl
> > has to maintain the PCI address (host domain/bus/slot/function to guest's
> > PHB BUID/bus/slot/function) mapping via KVM VFIO device. The address mapping
> > will be built when initializing VFIO device in QEMU and destroied when the
> > VFIO device in QEMU is going to offline, or VM is destroy.
>
> Do you also expose all those interfaces to user space? VFIO is as much
> about user space device drivers as it is about device assignment.
>
> I would like to first see an implementation that doesn't touch KVM
> emulation code at all but instead routes everything through QEMU. As a
> second step we can then accelerate performance critical paths inside of KVM.
>
> That way we ensure that user space device drivers have all the power
> over a device they need to drive it.
+1
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