Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash"

Chris Wright
2010-04-06T17:44:57Z

* Joerg Roedel (joro@8bytes.org) wrote:
> On Sun, Apr 04, 2010 at 02:44:36AM -0700, Eric W. Biederman wrote:
> > Joerg Roedel <joro@8bytes.org> writes:
> >
> > > On Sun, Apr 04, 2010 at 09:24:30AM +0200, Bernhard Walle wrote:
> > >> Am 03.04.10 19:49, schrieb Eric W. Biederman:
> > >> > Not a problem. We require a lot of things of the kdump kernel,
> > >> > and it is immediately apparent in a basic sanity test.
> > >>
> > >> Also, in most cases (for example: distribution kernels), the kdump
> > >> kernel nowadays is identical to the running kernel. So, if the running
> > >> kernel has IOMMU support, the kdump kernel also has.
> > >
> > > Yes, I know. But is that a requirement for kexec?
> >
> > For normal kexec no. That path is expected to do a clean hardware
> > shutdown.
> >
> > For kexec on panic aka kdump the requirement is that your your crash
> > kernel be able to initialize your hardware from any state it can be
> > put in.
>
> Ok, if you show me where this is documented for everybody then I am
> probably convinced :-)
> We should fixup the gart initialization anyway.

So, you planning to pull in all 4 patches then?

thanks,
-chris