On 03/14/2013 08:57:53 AM, Bhushan Bharat-R65777 wrote:
> >>> diff --git a/arch/powerpc/kvm/e500mc.c
b/arch/powerpc/kvm/e500mc.c
> >>> index 1f89d26..f5fc6f5 100644
> >>> --- a/arch/powerpc/kvm/e500mc.c
> >>> +++ b/arch/powerpc/kvm/e500mc.c
> >>> @@ -182,8 +182,7 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu
> >>> *vcpu) {
> >>> struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
> >>>
> >>> - vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS |
SPRN_EPCR_DGTMI | \
> >>> - SPRN_EPCR_DUVD;
> >>> + vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS |
SPRN_EPCR_DGTMI;
> >>
> >> Doesn't this route all debug events through the host?
> >
> > No; This means that debug events can occur in hypervisor state or
not.
> >
> > EPCR.DUVD = 0 ; Debug events can occur in the hypervisor state.
> >
> > EPCR.DUVD = 1 ; Debug events cannot occur in the hypervisor state.
> >
> > So we allow debug events to occur in hypervisor state.
>
> Why do we care about debug events in our entry/exit code and didn't
care about
> them before?
We care for single stepping in guest to not step in KVM code.
> If anything, this is a completely separate patch, orthogonal to
> this patch series, and requires a good bit of explanation.
Not sure why you think separate patch; this patch add support for
single stepping and also takes care that debug event does not comes
in host when doing single stepping.
How does *removing* DUVD ensure that?
-Scott
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