Re: [PATCH v5 3/5] KVM: arm64: Add support for PSCI v1.2 and v1.3

[Oliver Upton <oliver.upton@linux.dev>]

On Thu, Sep 26, 2024 at 07:37:58PM +0100, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>

Please, add changelogs to your patches.

What we really need here is the detail on *why* we can just bump the
PSCI version like this, i.e. no new required ABI. On top of that, you
could mention that KVM has made the implementation choice to provide
SYSTEM_OFF2 unconditionally in its PSCIv1.3 implementation.

> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>  arch/arm64/kvm/hypercalls.c | 2 ++
>  arch/arm64/kvm/psci.c       | 6 +++++-
>  include/kvm/arm_psci.h      | 4 +++-
>  3 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
> index 5763d979d8ca..9c6267ca2b82 100644
> --- a/arch/arm64/kvm/hypercalls.c
> +++ b/arch/arm64/kvm/hypercalls.c
> @@ -575,6 +575,8 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
>  		case KVM_ARM_PSCI_0_2:
>  		case KVM_ARM_PSCI_1_0:
>  		case KVM_ARM_PSCI_1_1:
> +		case KVM_ARM_PSCI_1_2:
> +		case KVM_ARM_PSCI_1_3:
>  			if (!wants_02)
>  				return -EINVAL;
>  			vcpu->kvm->arch.psci_version = val;
> diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
> index fd0f82464f7d..5177dda5a411 100644
> --- a/arch/arm64/kvm/psci.c
> +++ b/arch/arm64/kvm/psci.c
> @@ -328,7 +328,7 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
>  
>  	switch(psci_fn) {
>  	case PSCI_0_2_FN_PSCI_VERSION:
> -		val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
> +		val = PSCI_VERSION(1, minor);
>  		break;
>  	case PSCI_1_0_FN_PSCI_FEATURES:
>  		arg = smccc_get_arg1(vcpu);
> @@ -486,6 +486,10 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)
>  	}
>  
>  	switch (version) {
> +	case KVM_ARM_PSCI_1_3:
> +		return kvm_psci_1_x_call(vcpu, 3);
> +	case KVM_ARM_PSCI_1_2:
> +		return kvm_psci_1_x_call(vcpu, 2);
>  	case KVM_ARM_PSCI_1_1:
>  		return kvm_psci_1_x_call(vcpu, 1);
>  	case KVM_ARM_PSCI_1_0:
> diff --git a/include/kvm/arm_psci.h b/include/kvm/arm_psci.h
> index e8fb624013d1..cbaec804eb83 100644
> --- a/include/kvm/arm_psci.h
> +++ b/include/kvm/arm_psci.h
> @@ -14,8 +14,10 @@
>  #define KVM_ARM_PSCI_0_2	PSCI_VERSION(0, 2)
>  #define KVM_ARM_PSCI_1_0	PSCI_VERSION(1, 0)
>  #define KVM_ARM_PSCI_1_1	PSCI_VERSION(1, 1)
> +#define KVM_ARM_PSCI_1_2	PSCI_VERSION(1, 2)
> +#define KVM_ARM_PSCI_1_3	PSCI_VERSION(1, 3)
>  
> -#define KVM_ARM_PSCI_LATEST	KVM_ARM_PSCI_1_1
> +#define KVM_ARM_PSCI_LATEST	KVM_ARM_PSCI_1_3
>  
>  static inline int kvm_psci_version(struct kvm_vcpu *vcpu)
>  {
> -- 
> 2.44.0
> 

-- 
Thanks,
Oliver