On Thu, Mar 16, 2017 at 11:45:35AM +0000, Marc Zyngier wrote: > Similarily to the GICv2 case, we need to expose a PMR value that > is either the 8bit value (KVM_DEV_ARM_VGIC_CTRL_CANONICAL_PMR > being set) or the 5bit, truncated value otherwise. I'm a bit puzzled by this patch as well. The struct vmcr is an internal representation of the VMCR register fields without well-defined semantics of how the fields should be laid out. I think I would prefer it if we document on the vmcr struct which format the pmr field is in, and choose the actual ICC_PMR_EL1 or GICC_PMR format for this field, and then we leave the get/set_vmcr functions untouched. > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > virt/kvm/arm/vgic/vgic-v3.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c > index be0f4c3e0142..d260214a5bdb 100644 > --- a/virt/kvm/arm/vgic/vgic-v3.c > +++ b/virt/kvm/arm/vgic/vgic-v3.c > @@ -184,6 +184,17 @@ void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp) > vmcr |= (vmcrp->ctlr << ICH_VMCR_CBPR_SHIFT) & ICH_VMCR_CBPR_MASK; > vmcr |= (vmcrp->abpr << ICH_VMCR_BPR1_SHIFT) & ICH_VMCR_BPR1_MASK; > vmcr |= (vmcrp->bpr << ICH_VMCR_BPR0_SHIFT) & ICH_VMCR_BPR0_MASK; > + > + /* > + * If we're emulating GICv2 and that userspace can't deal with My comments above notwithstanding: s/that// > + * the normal PMR range (8 bits), we need to make it GICv3 > + * compatible by shifting the value by 3 bits in order to deal > + * with the full 8bit range. > + */ > + if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2 && > + !test_bit(VGIC_QUIRK_CANONICAL_PMR, &vcpu->kvm->arch.vgic.quirks)) > + vmcrp->pmr <<= 3; > + > vmcr |= (vmcrp->pmr << ICH_VMCR_PMR_SHIFT) & ICH_VMCR_PMR_MASK; > vmcr |= (vmcrp->grpen0 << ICH_VMCR_ENG0_SHIFT) & ICH_VMCR_ENG0_MASK; > vmcr |= (vmcrp->grpen1 << ICH_VMCR_ENG1_SHIFT) & ICH_VMCR_ENG1_MASK; > @@ -205,6 +216,16 @@ void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp) > vmcrp->abpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT; > vmcrp->bpr = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT; > vmcrp->pmr = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT; > + > + /* > + * If we're emulating GICv2 and that userspace DOES NOT deal s/that// nit: why do we write DOES NOT here i upper case (feels a bit aggressive)? > + * with the normal PMR range (8 bits), we need to reduce it to > + * the GICv2 range (5 bits). > + */ > + if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2 && > + !test_bit(VGIC_QUIRK_CANONICAL_PMR, &vcpu->kvm->arch.vgic.quirks)) > + vmcrp->pmr >>= 3; > + > vmcrp->grpen0 = (vmcr & ICH_VMCR_ENG0_MASK) >> ICH_VMCR_ENG0_SHIFT; > vmcrp->grpen1 = (vmcr & ICH_VMCR_ENG1_MASK) >> ICH_VMCR_ENG1_SHIFT; > } > -- > 2.11.0 > Thanks, -Christoffer
