diff mbox

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

Message ID 1396435347-20056-11-git-send-email-anup.patel@linaro.org
State New
Headers show

Commit Message

Anup Patel April 2, 2014, 10:42 a.m. UTC 
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@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
---
 arch/arm/kvm/psci.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

Comments

Rob Herring April 2, 2014, 1:12 p.m. UTC | #1 
On Wed, Apr 2, 2014 at 5:42 AM, Anup Patel <anup.patel@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@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> Reviewed-by: Christoffer Dall <christoffer.dall@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.

Rob
Anup Patel April 3, 2014, 5:06 a.m. UTC | #2 
On 2 April 2014 18:42, Rob Herring <robherring2@gmail.com> wrote:
> On Wed, Apr 2, 2014 at 5:42 AM, Anup Patel <anup.patel@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@linaro.org>
>> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
>> Reviewed-by: Christoffer Dall <christoffer.dall@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
diff mbox

Patch

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
@@ -63,6 +63,7 @@  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;
@@ -83,10 +84,17 @@  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);
 
@@ -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;
 	vcpu->arch.pause = false;
 	smp_mb();		/* Make sure the above is visible */