[PATCH v7 10/12] ARM/ARM64: KVM: Fix CPU_ON emulation for PSCI v0.2

[Anup Patel]

On 2 April 2014 18:42, Rob Herring <robherring2 at gmail.com> wrote:
> On Wed, Apr 2, 2014 at 5:42 AM, Anup Patel <anup.patel at linaro.org> wrote:
>> As-per PSCI v0.2, the source CPU provides physical address of
>> "entry point" and "context id" for starting a target CPU. Also,
>> if target CPU is already running then we should return ALREADY_ON.
>>
>> Current emulation of CPU_ON function does not consider physical
>> address of "context id" and returns INVALID_PARAMETERS if target
>> CPU is already running.
>>
>> This patch updates kvm_psci_vcpu_on() such that it works for both
>> PSCI v0.1 and PSCI v0.2.
>>
>> Signed-off-by: Anup Patel <anup.patel at linaro.org>
>> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
>> Reviewed-by: Christoffer Dall <christoffer.dall at linaro.org>
>> ---
>>  arch/arm/kvm/psci.c |   12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
>> index d8335da..fdbd829 100644
>> --- a/arch/arm/kvm/psci.c
>> +++ b/arch/arm/kvm/psci.c
>
>
>> @@ -101,6 +109,8 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>>                 kvm_vcpu_set_be(vcpu);
>>
>>         *vcpu_pc(vcpu) = target_pc;
>> +       if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
>> +               *vcpu_reg(vcpu, 0) = context_id;
>
> This could be done unconditionally. The register value is undefined
> for 0.1, so whatever was in r3/x3 meets that requirement.

I had similar thought when I first updated this but then
I was not sure if PSCI v0.1 assumes this register to be
undefined.

Let me update this unconditionally as-per your suggestion
and put a comment here.

>
> Rob

--
Anup