[PATCH v9 10/12] ARM/ARM64: KVM: Fix CPU_ON emulation for PSCI v0.2

[Marc Zyngier]

On Tue, Apr 15 2014 at  7:14:13 am BST, 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>

Acked-by: Marc Zyngier <marc.zyngier at arm.com>

> ---
>  arch/arm/kvm/psci.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
> index 1af0016..f59f09d 100644
> --- a/arch/arm/kvm/psci.c
> +++ b/arch/arm/kvm/psci.c
> @@ -48,6 +48,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  	struct kvm_vcpu *vcpu = NULL, *tmp;
>  	wait_queue_head_t *wq;
>  	unsigned long cpu_id;
> +	unsigned long context_id;
>  	unsigned long mpidr;
>  	phys_addr_t target_pc;
>  	int i;
> @@ -68,10 +69,17 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  	 * Make sure the caller requested a valid CPU and that the CPU is
>  	 * turned off.
>  	 */
> -	if (!vcpu || !vcpu->arch.pause)
> +	if (!vcpu)
>  		return PSCI_RET_INVALID_PARAMS;
> +	if (!vcpu->arch.pause) {
> +		if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
> +			return PSCI_RET_ALREADY_ON;
> +		else
> +			return PSCI_RET_INVALID_PARAMS;
> +	}
>  
>  	target_pc = *vcpu_reg(source_vcpu, 2);
> +	context_id = *vcpu_reg(source_vcpu, 3);
>  
>  	kvm_reset_vcpu(vcpu);
>  
> @@ -86,6 +94,11 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  		kvm_vcpu_set_be(vcpu);
>  
>  	*vcpu_pc(vcpu) = target_pc;
> +	/*
> +	 * NOTE: We always update r0 (or x0) because for PSCI v0.1
> +	 * the general puspose registers are undefined upon CPU_ON.
> +	 */
> +	*vcpu_reg(vcpu, 0) = context_id;
>  	vcpu->arch.pause = false;
>  	smp_mb();		/* Make sure the above is visible */

-- 
Jazz is not dead. It just smells funny.