On 05/10/2013 01:20:33 PM, Caraman Mihai Claudiu-B02008 wrote:
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Friday, May 10, 2013 8:42 PM
> To: Caraman Mihai Claudiu-B02008
> Cc: Alexander Graf; Wood Scott-B07421; kvm-ppc@xxxxxxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] kvm/ppc/booke64: fix build breakage from
Altivec,
> and disable e6500
>
> On 05/10/2013 09:11:24 AM, Caraman Mihai Claudiu-B02008 wrote:
> > > -----Original Message-----
> > > From: Alexander Graf [mailto:agraf@xxxxxxx]
> > > Sent: Friday, May 10, 2013 4:16 PM
> > > To: Caraman Mihai Claudiu-B02008
> > > Cc: Wood Scott-B07421; kvm-ppc@xxxxxxxxxxxxxxx;
kvm@xxxxxxxxxxxxxxx
> > > Subject: Re: [PATCH] kvm/ppc/booke64: fix build breakage from
> > Altivec,
> > > and disable e6500
> > >
> > >
> > > On 10.05.2013, at 11:40, Caraman Mihai Claudiu-B02008 wrote:
> > >
> > > >> -----Original Message-----
> > > >> From: Wood Scott-B07421
> > > >> Sent: Friday, May 10, 2013 6:15 AM
> > > >> To: Alexander Graf
> > > >> Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Wood
> > Scott-B07421;
> > > >> Caraman Mihai Claudiu-B02008
> > > >> Subject: [PATCH] kvm/ppc/booke64: fix build breakage from
> > Altivec, and
> > > >> disable e6500
> > > >>
> > > >> BookE altivec support brought two new exceptions, but KVM
was not
> > > >> updated, so the build broke for all 64-bit booke with KVM
> > enabled.
> > > >
> > > > We couldn't do that in KVM before having
> > > BOOKE_INTERRUPT_ALTIVEC_UNAVAIL/
> > > > BOOKE_INTERRUPT_ALTIVEC_ASSIST. As Tiejun noticed earlier we
> > should
> > > have
> > > > done this in Kumar's tree but we missed that chance. We will
face
> > > similar
> > > > issues every time an exception handler will be added.
> > >
> > > How hard would it be to add? I suppose it's broken in 3.10, so
we
> > need
> > > something quick before it gets released?
> >
> > Not so hard. Yes. I was surprised by this patch given the fact
that
> > we have
> > planned to send altivec support upstream this days and that we
> > already have
> > a similar patch from Tiejun on our list.
>
> I didn't see Tiejun's patch... My goal was just to fix the build
break
> without exposing problems, and to encourage a patch to fix it
properly
> to happen sooner rather than later. With Tiejun's patch, which is
> similar to mine except that it doesn't disable e6500 support, a user
> could BUG() the kernel by forcing an Altivec exception in a guest.
I
> didn't want to go further down the road of adding reflectors for
those
> exceptions, which could make it look like the problem was dealt with
> even though it's still not done.
I agree it's quite annoying to hit a build breakage. Reflection is not
a proper solution for this problem (though we will require it later)
but program exception injection looks feasible as a simple fix.
Program exception injection still doesn't deal with state corruption.
I wouldn't want to see e6500 removed for this reason.
It's not being removed, just closed while under construction to prevent
damage to people passing through. :-)
-Scott
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