Re: [PATCH 2/6] KVM: PPC: BOOKE: Force MSR_DE in rfci if guest is under debug

[Scott Wood <scottwood@freescale.com>]

On Fri, 2014-07-11 at 14:08 +0530, Bharat Bhushan wrote:
> When userspace (QEMU) is using the debug resource to debug guest
> then we want MSR_DE to be always set. This patch adds missing
> MSR_DE setting in "rfci" instruction.
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
> ---
>  arch/powerpc/kvm/booke_emulate.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
> index 27a4b28..80c51a2 100644
> --- a/arch/powerpc/kvm/booke_emulate.c
> +++ b/arch/powerpc/kvm/booke_emulate.c
> @@ -40,7 +40,11 @@ static void kvmppc_emul_rfi(struct kvm_vcpu *vcpu)
>  static void kvmppc_emul_rfci(struct kvm_vcpu *vcpu)
>  {
>  	vcpu->arch.pc = vcpu->arch.csrr0;
> -	kvmppc_set_msr(vcpu, vcpu->arch.csrr1);
> +	/* Force MSR_DE when guest does not own debug facilities */
> +	if (vcpu->guest_debug)
> +		kvmppc_set_msr(vcpu, vcpu->arch.csrr1 | MSR_DE);
> +	else
> +		kvmppc_set_msr(vcpu, vcpu->arch.csrr1);
>  }
>  
>  int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,

It looks like this is already handled by kvmppc_vcpu_sync_debug(), which
is called by kvmppc_set_msr().

Plus, it should only be done for HV mode.

-Scott