Re: [Minios-devel] [UNIKRAFT PATCHv4 38/43] plat/kvm: Implement shutdown for Arm64

[Julien Grall <julien.grall@xxxxxxx>]

Hi Wei,

On 06/07/18 10:03, Wei Chen wrote:
> QEMU/KVM provide a PSCI interface for virtual machine on
> Arm64 platform. So we use this interface to implement
> platform system off function.
>
> Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> ---
>   plat/kvm/shutdown.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/plat/kvm/shutdown.c b/plat/kvm/shutdown.c
> index a513df9..0f0a01f 100644
> --- a/plat/kvm/shutdown.c
> +++ b/plat/kvm/shutdown.c
> @@ -22,7 +22,8 @@
>    */
>   
>   #include <errno.h>
> -#include <x86/cpu.h>
> +#include <cpu.h>
> +#include <irq.h>
>   #include <uk/print.h>
>   #include <uk/plat/bootstrap.h>
>   
> @@ -38,7 +39,11 @@ void ukplat_terminate(enum ukplat_gstate request __unused)
>          * be 83 ('S', 41 << 1 | 1).
>          */
>         uk_printk("Unikraft halted\n");
> +#if defined(__X86_64__)
>         outw(0x501, 41);
> +#elif defined(__ARM_64__)
> +       system_off();
> +#endif
>   
>   	/*
>          * If we got here, there is no way to initiate "shutdown" on virtio
> @@ -49,7 +54,9 @@ void ukplat_terminate(enum ukplat_gstate request __unused)
>   
>   static void cpu_halt(void)
>   {
> -       __asm__ __volatile__("cli; hlt");
> +       local_irq_disable();
> +       halt();
I think you want to move halt() in the for loop for Arm because WFI will 
come back when an interrupt is received. This means you will go into a 
busy loop wasting power.
> +
>         for (;;)
>                 ;
>   }
Cheers,

--
Julien Grall

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