Re: [Qemu-devel] [PATCH RFC v11 3/4] vfio-pci: pass the aer error to guest

[Tian, Kevin]

> From: Alex Williamson
> Sent: Thursday, January 19, 2017 6:32 AM
> 
> On Sat, 31 Dec 2016 17:13:07 +0800
> Cao jin <address@hidden> wrote:
> 
> > From: Chen Fan <address@hidden>
> >
> > When physical device has uncorrectable error hanppened, the vfio_pci
> > driver will signal the uncorrectable error status register value to
> > corresponding QEMU's vfio-pci device via the eventfd registered by this
> > device, then, the vfio-pci's error eventfd handler will be invoked in
> > event loop.
> >
> > Construct and pass the aer message to root port, root port will trigger an
> > interrupt to signal guest, then, the guest driver will do the recovery.
> >
> > Note: Now only support non-fatal error's recovery, fatal error will
> > still result in vm stop.
> 
> Please update the entire commit log, don't just add a note that this
> now only covers non-fatal errors.
> 

One thing relate to vIOMMU. There is still a TODO task about forwarding
IOMMU fault thru VFIO to Qemu, so Qemu vIOMMU has the chance to
walk guest remapping structure to emulate virtual IOMMU fault. Likely
it also requires eventfd mechanism.

Wondering whether making sense to reuse same eventfd for both AER
and vIOMMU or using separate eventfd is also fine? Even go with the
former option, I don't expect substantial change to this series. Major
change is on interface definition - extensible to multiple types of 
fault/error conditions instead of assuming AER only.

Thoughts?

Thanks
Kevin