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

[Anup Patel <anup.patel@linaro.org>]

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.

--
Anup

>
> Will