[RFC PATCH 02/17] KVM: PPC64: booke: Add EPCR support in mtspr/mfspr emulation

[Caraman Mihai Claudiu-B02008]

> -----Original Message-----
> From: kvm-ppc-owner at vger.kernel.org [mailto:kvm-ppc-
> owner at vger.kernel.org] On Behalf Of Alexander Graf
> Sent: Wednesday, July 04, 2012 4:22 PM
> To: Caraman Mihai Claudiu-B02008
> Cc: kvm-ppc at vger.kernel.org; kvm at vger.kernel.org; linuxppc-
> dev at lists.ozlabs.org; qemu-ppc at nongnu.org
> Subject: Re: [RFC PATCH 02/17] KVM: PPC64: booke: Add EPCR support in
> mtspr/mfspr emulation
> 
> 
> On 25.06.2012, at 14:26, Mihai Caraman wrote:
> 
> > Add EPCR support in booke mtspr/mfspr emulation. EPCR register is
> defined
> > only for 64-bit and HV categories, so it shoud be available only on 64-
> bit
> > virtual processors. Undefine the support for 32-bit builds.
> > Define a reusable setter function for vcpu's EPCR.
> >
> > Signed-off-by: Mihai Caraman <mihai.caraman at freescale.com>
> > ---
> > arch/powerpc/kvm/booke.c         |   12 +++++++++++-
> > arch/powerpc/kvm/booke.h         |    6 ++++++
> > arch/powerpc/kvm/booke_emulate.c |   13 ++++++++++++-
> > 3 files changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> > index 72f13f4..f9fa260 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -13,7 +13,7 @@
> >  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
> USA.
> >  *
> >  * Copyright IBM Corp. 2007
> > - * Copyright 2010-2011 Freescale Semiconductor, Inc.
> > + * Copyright 2010-2012 Freescale Semiconductor, Inc.
> >  *
> >  * Authors: Hollis Blanchard <hollisb at us.ibm.com>
> >  *          Christian Ehrhardt <ehrhardt at linux.vnet.ibm.com>
> > @@ -1243,6 +1243,16 @@ void kvmppc_core_commit_memory_region(struct kvm
> *kvm,
> > {
> > }
> >
> > +#ifdef CONFIG_64BIT
> > +void kvmppc_set_epcr(struct kvm_vcpu *vcpu, u32 new_epcr)
> > +{
> > +	vcpu->arch.epcr = new_epcr;
> > +	vcpu->arch.shadow_epcr &= ~SPRN_EPCR_GICM;
> > +	if (vcpu->arch.epcr  & SPRN_EPCR_ICM)
> > +		vcpu->arch.shadow_epcr |= SPRN_EPCR_GICM;
> 
> Why would the setter be #ifdef CONFIG_64BIT? EPCR exists on e500mc too,
> no? Please only #ifdef the GICM bits out.

kvmppc_set_epcr deals with guest EPCR and EPCR does not exist on a virtual e500mc
as detailed in patch's comment. All callers are also guarded by #ifdef CONFIG_64BIT,
my assumption was that we will not support a virtual core with 64-bit category
on a 32-bit host.

> 
> 
> Alex
> 
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