Re: [PATCH 5/5] kvmtool: ARM/ARM64: Provide PSCI-0.2 guest when in-kernel KVM supports it

[Will Deacon <will.deacon@arm.com>]

On Thu, Aug 07, 2014 at 10:00:13AM +0100, Anup Patel wrote:
> On 6 August 2014 18:26, Will Deacon <will.deacon@arm.com> wrote:
> > On Tue, Aug 05, 2014 at 09:49:59AM +0100, Anup Patel wrote:
> >> If in-kernel KVM support PSCI-0.2 emulation then we should set
> >> KVM_ARM_VCPU_PSCI_0_2 feature for each guest VCPU and also
> >> provide "arm,psci-0.2","arm,psci" as PSCI compatible string.
> >>
> >> This patch updates kvm_cpu__arch_init() and setup_fdt() as
> >> per above.
> >>
> >> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> >> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> >> ---
> >>  tools/kvm/arm/fdt.c     |   39 +++++++++++++++++++++++++++++++++------
> >>  tools/kvm/arm/kvm-cpu.c |    5 +++++
> >>  2 files changed, 38 insertions(+), 6 deletions(-)
> >
> > [...]
> >
> >> diff --git a/tools/kvm/arm/kvm-cpu.c b/tools/kvm/arm/kvm-cpu.c
> >> index 7478f8f..76c28a0 100644
> >> --- a/tools/kvm/arm/kvm-cpu.c
> >> +++ b/tools/kvm/arm/kvm-cpu.c
> >> @@ -74,6 +74,11 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> >>               die("preferred target not available\n");
> >>       }
> >>
> >> +     /* Set KVM_ARM_VCPU_PSCI_0_2 if available */
> >> +     if (kvm__supports_extension(kvm, KVM_CAP_ARM_PSCI_0_2)) {
> >> +             vcpu_init.features[0] |= (1UL << KVM_ARM_VCPU_PSCI_0_2);
> >> +     }
> >
> > Where is this used?
> 
> If we want to provide PSCI-0.2 to Guest then we should inform
> in-kernel KVM ARM/ARM64 using init features.
> 
> By default KVM ARM/ARM64 provides PSCI-0.1 to Guest. If we don't set
> this feature then Guest will get undefined exception for PSCI-0.2
> calls.

Gotcha, thanks for the explanation.

Will