[PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
Christoffer Dall
christoffer.dall at linaro.org
Fri Dec 13 15:08:34 EST 2013
On Thu, Dec 12, 2013 at 09:42:27PM +0530, Anup Patel wrote:
> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
> functions hence cannot be fully emulated by the in-kernel PSCI
> emulation code.
>
> To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
> calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
> structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
>
> Signed-off-by: Anup Patel <anup.patel at linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
> ---
> arch/arm/include/asm/kvm_psci.h | 2 +-
> arch/arm/include/uapi/asm/kvm.h | 2 ++
> arch/arm/kvm/handle_exit.c | 13 +++++++---
> arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
> arch/arm64/include/asm/kvm_psci.h | 2 +-
> arch/arm64/include/uapi/asm/kvm.h | 2 ++
> arch/arm64/kvm/handle_exit.c | 12 +++++++---
> 7 files changed, 65 insertions(+), 16 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
> index 9a83d98..992d7f1 100644
> --- a/arch/arm/include/asm/kvm_psci.h
> +++ b/arch/arm/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
> #ifndef __ARM_KVM_PSCI_H__
> #define __ARM_KVM_PSCI_H__
>
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM_KVM_PSCI_H__ */
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index c498b60..f4de20c 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>
> #define KVM_PSCI_RET_SUCCESS 0
> #define KVM_PSCI_RET_NI ((unsigned long)-1)
> diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
> index a920790..c3f0e72 100644
> --- a/arch/arm/kvm/handle_exit.c
> +++ b/arch/arm/kvm/handle_exit.c
> @@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> + int ret;
> +
> trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
> kvm_vcpu_hvc_get_imm(vcpu));
>
> - if (kvm_psci_call(vcpu))
> + ret = kvm_psci_call(vcpu);
> + if (ret >= 0)
> + return ret;
> + else if (ret == -EINVAL) {
> + kvm_inject_undefined(vcpu);
> return 1;
> + }
> +
> + return ret;
Wouldn't
ret = kvm_psci_call(vcpu);
if (ret == -EINVAL) {
kvm_inject_undefined(vcpu);
return 1;
}
return ret;
be simpler?
also, minor nit, but I think according to the CodingStyle if you have
single statements in if cases, but they are part of a larger if
statement with alternative clauses that use curly-brackets to
encapsulate multiple statements, then you should use curly braces around
the single-line statement as well...
>
> - kvm_inject_undefined(vcpu);
> - return 1;
> }
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
> index 0881bf1..8e246d6 100644
> --- a/arch/arm/kvm/psci.c
> +++ b/arch/arm/kvm/psci.c
> @@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> return KVM_PSCI_RET_SUCCESS;
> }
>
> +static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> +{
> + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> + vcpu->run->system_event.type = type;
> + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> +}
> +
> +static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
> +{
> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> +}
> +
> +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
> +{
> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
> +}
> +
> /**
> * kvm_psci_call - handle PSCI call if r0 value is in range
> * @vcpu: Pointer to the VCPU struct
> *
> * Handle PSCI calls from guests through traps from HVC instructions.
> - * The calling convention is similar to SMC calls to the secure world where
> - * the function number is placed in r0 and this function returns true if the
> - * function number specified in r0 is withing the PSCI range, and false
> - * otherwise.
> + * The calling convention is similar to SMC calls to the secure world
> + * where the function number is placed in r0 and function number
the function number
> + * specified in r0 is withing the PSCI range.
this reads a little funny now. I think you can get rid of everything
after the first mention of r0 (cut from "and function number...") since
you explain that in the error codes below.
> + *
> + * This function returns: > 0 (success), 0 (success but exit to user
> + * space), and < 0 (errors)
you could use @return: instead of "This function returns", but I'm not
sure if anyone actually cares.
> + *
> + * Errors:
> + * -EINVAL: Unrecognized PSCI function
> */
> -bool kvm_psci_call(struct kvm_vcpu *vcpu)
> +int kvm_psci_call(struct kvm_vcpu *vcpu)
> {
> + int ret = 1;
> unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
> unsigned long val;
>
> @@ -111,11 +134,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
> case KVM_PSCI_FN_MIGRATE:
> val = KVM_PSCI_RET_NI;
> break;
> -
> + case KVM_PSCI_FN_SYSTEM_OFF:
> + kvm_psci_system_off(vcpu);
> + val = KVM_PSCI_RET_SUCCESS;
> + ret = 0;
> + break;
> + case KVM_PSCI_FN_SYSTEM_RESET:
> + kvm_psci_system_reset(vcpu);
> + val = KVM_PSCI_RET_SUCCESS;
> + ret = 0;
> + break;
> default:
> - return false;
> + return -EINVAL;
> }
>
> *vcpu_reg(vcpu, 0) = val;
> - return true;
> + return ret;
> }
> diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
> index e301a48..9bd0ee8 100644
> --- a/arch/arm64/include/asm/kvm_psci.h
> +++ b/arch/arm64/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
> #ifndef __ARM64_KVM_PSCI_H__
> #define __ARM64_KVM_PSCI_H__
>
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM64_KVM_PSCI_H__ */
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index d9f026b..f678902 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -158,6 +158,8 @@ struct kvm_arch_memory_slot {
> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>
> #define KVM_PSCI_RET_SUCCESS 0
> #define KVM_PSCI_RET_NI ((unsigned long)-1)
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index df84d7b..e382eb8 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -30,11 +30,17 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
>
> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> - if (kvm_psci_call(vcpu))
> + int ret;
> +
> + ret = kvm_psci_call(vcpu);
> + if (ret >= 0)
> + return ret;
> + else if (ret == -EINVAL) {
> + kvm_inject_undefined(vcpu);
> return 1;
> + }
>
> - kvm_inject_undefined(vcpu);
> - return 1;
> + return ret;
same as above.
> }
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> --
> 1.7.9.5
>
Aside from the code formatting and commenting above, it looks pretty
good to me.
-Christoffer
More information about the linux-arm-kernel
mailing list