Re: [PATCH] pci-assign: Do not reset the device unless the kernel supports it

[Avi Kivity <avi@redhat.com>]

On 06/07/2011 01:04 AM, Jan Kiszka wrote:
> On 2011-06-06 23:48, Alex Williamson wrote:
> >  On Mon, 2011-06-06 at 23:30 +0200, Jan Kiszka wrote:
> >>  From: Jan Kiszka<jan.kiszka@siemens.com>
> >>
> >>  At least kernels 2.6.38 and 2.6.39 do not properly support issuing a
> >>  reset on an assigned device and corrupt its config space. Prevent
> >>  this by checking for a host kernel with the required support, tagged by
> >>  the to-be-introduced KVM_CAP_DEVICE_RESET.
> >
> >  Wouldn't it be easier just to revert ed78661f in 2.6.39 stable?  I guess
> >  we don't have an option to do that for .38 since stable is done there,
> >  but there are also some intel-iommu breakages that won't make stable for
> >  that release.  It seems like the userspace invoked reset resolves known,
> >  demonstrable issues of devices continuing to DMA into guest memory while
> >  ed78661f is mostly a theoretical change.
>
> Easier would be this patch. But I don't mind reverting the problematic
> commit in 39, whatever is preferred. We should just resolve the issue
> finally.

Kernel problems should be solved in the kernel (with exceptions of 
course, but don't see the need here).


-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.