On Mon, 2014-08-04 at 13:32 +0530, Bharat Bhushan wrote:
> @@ -735,7 +745,27 @@ static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
> struct debug_reg *dbg_reg = &(vcpu->arch.shadow_dbg_reg);
> u32 dbsr = vcpu->arch.dbsr;
>
> - /* Clear guest dbsr (vcpu->arch.dbsr).
> + if (vcpu->guest_debug == 0) {
> + /*
> + * Debug resources belong to Guest.
> + * Imprecise debug event are not injected
> + */
> + if (dbsr & DBSR_IDE)
> + return RESUME_GUEST;
This is incorrect. DBSR_IDE shouldn't *cause* an injection, but it
shouldn't inhibit it either.
> @@ -828,6 +858,8 @@ static void kvmppc_restart_interrupt(struct kvm_vcpu *vcpu,
> case BOOKE_INTERRUPT_DEBUG:
> /* Save DBSR before preemption is enabled */
> vcpu->arch.dbsr = mfspr(SPRN_DBSR);
> + /* MASK out DBSR_MRR */
> + vcpu->arch.dbsr &= ~DBSR_MRR;
> kvmppc_clear_dbsr();
> break;
> }
DBSR[MRR] can only be set once per host system reset. There's no need
to filter it out here; just make sure the host clears it at some point
before this point. The MRR value doesn't currently survive past
kvmppc_clear_dbsr(), so this isn't helping to preserve it for the host's
benefit...
> @@ -1858,6 +1890,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
>
> if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
> vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
> + vcpu->arch.dbg_reg.dbcr0 = 0;
Again, it's not clear why we need shadow debug registers here. "Just in
case we implement something that can't be implemented" isn't a good
reason to keep complexity around.
-Scott
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