Re: [PATCH 15/19] KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting

[Marc Zyngier <maz@kernel.org>]

On Thu, 14 Jul 2022 07:37:25 +0100,
Reiji Watanabe <reijiw@google.com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jul 6, 2022 at 10:05 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > We carry a legacy interface to set the base addresses for GICv2.
> > As this is currently plumbed into the same handling code as
> > the modern interface, it limits the evolution we can make there.
> >
> > Add a helper dedicated to this handling, with a view of maybe
> > removing this in the future.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/arm.c                  | 11 ++-------
> >  arch/arm64/kvm/vgic/vgic-kvm-device.c | 32 +++++++++++++++++++++++++++
> >  include/kvm/arm_vgic.h                |  1 +
> >  3 files changed, 35 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index 83a7f61354d3..bf39570c0aef 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -1414,18 +1414,11 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
> >  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
> >                                         struct kvm_arm_device_addr *dev_addr)
> >  {
> > -       unsigned long dev_id, type;
> > -
> > -       dev_id = (dev_addr->id & KVM_ARM_DEVICE_ID_MASK) >>
> > -               KVM_ARM_DEVICE_ID_SHIFT;
> > -       type = (dev_addr->id & KVM_ARM_DEVICE_TYPE_MASK) >>
> > -               KVM_ARM_DEVICE_TYPE_SHIFT;
> > -
> > -       switch (dev_id) {
> > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> >         case KVM_ARM_DEVICE_VGIC_V2:
> >                 if (!vgic_present)
> >                         return -ENXIO;
> > -               return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
> > +               return kvm_set_legacy_vgic_v2_addr(kvm, dev_addr);
> >         default:
> >                 return -ENODEV;
> >         }
> > diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > index fbbd0338c782..0dfd277b9058 100644
> > --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
> > @@ -41,6 +41,38 @@ static int vgic_check_type(struct kvm *kvm, int type_needed)
> >                 return 0;
> >  }
> >
> > +int kvm_set_legacy_vgic_v2_addr(struct kvm *kvm, struct kvm_arm_device_addr *dev_addr)
> > +{
> > +       struct vgic_dist *vgic = &kvm->arch.vgic;
> > +       int r;
> > +
> > +       mutex_lock(&kvm->lock);
> > +       switch (FIELD_GET(KVM_ARM_DEVICE_ID_MASK, dev_addr->id)) {
> 
> Shouldn't this be KVM_ARM_DEVICE_TYPE_MASK (not KVM_ARM_DEVICE_ID_MASK) ?

Damn, you just ruined my attempt at deprecating this API ;-). More
seriously, thanks for catching this one!

	M.

-- 
Without deviation from the norm, progress is not possible.

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