> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, July 29, 2014 3:22 AM
> To: Bhushan Bharat-R65777
> Cc: ag...@suse.de; kvm-ppc@vger.kernel.org; k...@vger.kernel.org; Yoder 
> Stuart-
> B08248
> Subject: Re: [PATCH 1/6] KVM: PPC: BOOKE: No need to set DBCR0_EDM in guest
> visible register
> 
> On Fri, 2014-07-11 at 14:08 +0530, Bharat Bhushan wrote:
> > This is not used and  even I do not remember why this was added in
> > first place.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> > ---
> >  arch/powerpc/kvm/booke.c | 2 --
> >  1 file changed, 2 deletions(-)
> >
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index
> > ab62109..a5ee42c 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -1804,8 +1804,6 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct 
> > kvm_vcpu
> *vcpu,
> >     kvm_guest_protect_msr(vcpu, MSR_DE, true);
> >     vcpu->guest_debug = dbg->control;
> >     vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> > -   /* Set DBCR0_EDM in guest visible DBCR0 register. */
> > -   vcpu->arch.dbg_reg.dbcr0 = DBCR0_EDM;
> >
> >     if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
> >             vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
> 
> This was intended to let the guest know that the host owns the debug 
> resources,
> by analogy to what a JTAG debugger would do.
> 
> The Power ISA has this "Virtualized Implementation Note":
> 
>         It is the responsibility of the hypervisor to ensure that
>         DBCR0[EDM] is consistent with usage of DEP.

Ok, That means that if MSRP_DEP is set then set DBCR0_EDM  and if MSRP_DEP is 
clear then clear DBCR0_EDM, right?
We need to implement above mentioned this.

Thanks
-Bharat

> 
> -Scott
> 

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