Re: [Qemu-devel] [Qemu-ppc] [PATCH 1/2] PPC: Fix interrupt MSR value within the PPC interrupt handler.

[Mark Cave-Ayland]

On 29/03/12 20:06, Scott Wood wrote:

> > > Hrm, yeah.  I think what you ought to do is to use the new logic just
> > > for the "classic" exception models.  Have the default branch remain
> > > the one that just masks ME.  That's wrong, but it's the same wrong as
> > > we have already, and we can fix it later once we've verified what the
> > > right thing to do is for 40x and BookE.

Agreed. I've just reworked the patch based on yours/David's comments so 
that it should minimise the effect of any changes.

> > I'm actually coming at this from a fixing what was potentially an
> > OpenBIOS bug rather than a PPC angle, so I have to admit I have no I
> > idea which ones are the "classic" exception models. Would you consider
> > this to be just EXCP_STD, EXCP_6* and EXCP_7*?
>
> Also POWERPC_EXCP_G2, and maybe POWERPC_EXCP_970?  Even on server
> there's a question of whether it's a 2.06 chip or previous version of
> the architecture.
>
> One thing that sticks out for classic chips that is missing here is
> MSR[POW], which should be cleared on exceptions.

I'm not sure about _970 given that it's 64-bit, so I've left this on the 
old behaviour for the time being and altered the patch so that MSR_POW 
is now cleared in the classic exception path too.

I see that Andreas has already applied the second patch in the series to 
ppc-next, so I'll just resubmit a revised version of the first patch 
shortly.


ATB,

Mark.