Re: [PATCH 12/19] xen/arm: Implement PSCI SYSTEM_SUSPEND call (physical interface)

[Julien Grall <julien@xxxxxxx>]

Hi,

On 07/10/2022 11:32, Mykyta Poturai wrote:
> From: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
>
> PSCI system suspend function shall be invoked to finalize Xen suspend
> procedure. Resume entry point, which needs to be passed via 1st argument
> of PSCI system suspend call to the EL3, is hyp_resume. For now, hyp_resume
> is just a placeholder that will be implemented in assembly. Context ID,
> which is 2nd argument of system suspend PSCI call, is unused, as in Linux.
>
> Update: moved hyp_resume to head.S to place it near the rest of the
> start code
>
> Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
> Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xxxxxxxxxx>
> Signed-off-by: Mykyta Poturai <mykyta_poturai@xxxxxxxx>
> ---
>   xen/arch/arm/arm64/head.S     |  3 +++
>   xen/arch/arm/psci.c           | 16 ++++++++++++++++
>   xen/arch/arm/suspend.c        |  4 ++++
>   xen/include/asm-arm/psci.h    |  1 +
>   xen/include/asm-arm/suspend.h |  1 +
>   5 files changed, 25 insertions(+)
>
> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
> index aa1f88c764..8857955699 100644
> --- a/xen/arch/arm/arm64/head.S
> +++ b/xen/arch/arm/arm64/head.S
> @@ -957,6 +957,9 @@ ENTRY(efi_xen_start)
>           b     real_start_efi
>   ENDPROC(efi_xen_start)
>   
> +ENTRY(hyp_resume)
> +        b .
This needs to be part of the idmap. At the moment, this will only cover 
up to _end_boot.
> +
>   /*
>    * Local variables:
>    * mode: ASM
> diff --git a/xen/arch/arm/psci.c b/xen/arch/arm/psci.c
> index 0c90c2305c..43a67eb345 100644
> --- a/xen/arch/arm/psci.c
> +++ b/xen/arch/arm/psci.c
> @@ -25,6 +25,7 @@
>   #include <asm/cpufeature.h>
>   #include <asm/psci.h>
>   #include <asm/acpi.h>
> +#include <asm/suspend.h>
>   
>   /*
>    * While a 64-bit OS can make calls with SMC32 calling conventions, for
> @@ -68,6 +69,21 @@ void call_psci_cpu_off(void)
>       }
>   }
>   
> +int call_psci_system_suspend(void)
> +{
> +#ifdef CONFIG_ARM_64
> +    struct arm_smccc_res res;
> +
> +    /* 2nd argument (context ID) is not used */
> +    arm_smccc_smc(PSCI_1_0_FN64_SYSTEM_SUSPEND, __pa(hyp_resume), &res);
> +
> +    return PSCI_RET(res);
> +#else
> +    /* not supported */
> +    return 1;
> +#endif
> +}
> +
>   void call_psci_system_off(void)
>   {
>       if ( psci_ver > PSCI_VERSION(0, 1) )
> diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
> index 05c43ce502..a0258befc9 100644
> --- a/xen/arch/arm/suspend.c
> +++ b/xen/arch/arm/suspend.c
> @@ -161,6 +161,10 @@ static long system_suspend(void *data)
>           goto resume_irqs;
>       }
>   
> +    status = call_psci_system_suspend();
> +    if ( status )
> +        dprintk(XENLOG_ERR, "PSCI system suspend failed, err=%d\n", status);
> +
>       system_state = SYS_STATE_resume;
>   
>       gic_resume();
> diff --git a/xen/include/asm-arm/psci.h b/xen/include/asm-arm/psci.h
> index 26462d0c47..9f6116a224 100644
> --- a/xen/include/asm-arm/psci.h
> +++ b/xen/include/asm-arm/psci.h
> @@ -20,6 +20,7 @@ extern uint32_t psci_ver;
>   
>   int psci_init(void);
>   int call_psci_cpu_on(int cpu);
> +int call_psci_system_suspend(void);
>   void call_psci_cpu_off(void);
>   void call_psci_system_off(void);
>   void call_psci_system_reset(void);
> diff --git a/xen/include/asm-arm/suspend.h b/xen/include/asm-arm/suspend.h
> index fbaa414f0c..29420e27fa 100644
> --- a/xen/include/asm-arm/suspend.h
> +++ b/xen/include/asm-arm/suspend.h
> @@ -3,6 +3,7 @@
>   
>   int32_t domain_suspend(register_t epoint, register_t cid);
>   void vcpu_resume(struct vcpu *v);
> +void hyp_resume(void);
>   
>   #endif
>   
Cheers,

--
Julien Grall