Re: [Xen-devel] [PATCH v3] hvm: Allow triple fault to imply crash rather than reboot

[Keir Fraser <keir@xxxxxxx>]

On 14/02/2013 13:00, "Andrew Cooper" <andrew.cooper3@xxxxxxxxxx> wrote:

> While the triple fault action on native hardware will result in a system
> reset, any modern operating system can and will make use of less violent
> reboot methods.  As a result, the most likely cause of a triple fault is a
> fatal software bug.
> 
> This patch allows the toolstack to indicate that a triple fault should mean a
> crash rather than a reboot.  The default of reboot still remains the same.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Acked-by: Keir Fraser <keir@xxxxxxx>

> --
> Changes since v2:
>  * Allow any SHUTDOWN_* values to be set
> Changes since v1:
>  * "reboot" -> "reset"
>  * v->domain -> d
> 
> diff -r 63594ce1708f -r dc98663be34e xen/arch/x86/hvm/hvm.c
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -540,6 +540,7 @@ int hvm_domain_initialise(struct domain
>      hvm_init_guest_time(d);
>  
>      d->arch.hvm_domain.params[HVM_PARAM_HPET_ENABLED] = 1;
> +    d->arch.hvm_domain.params[HVM_PARAM_TRIPLE_FAULT_REASON] =
> SHUTDOWN_reboot;
>  
>      hvm_init_cacheattr_region_list(d);
>  
> @@ -1244,9 +1245,13 @@ void hvm_hlt(unsigned long rflags)
>  void hvm_triple_fault(void)
>  {
>      struct vcpu *v = current;
> +    struct domain *d = v->domain;
> +    u8 reason = d->arch.hvm_domain.params[HVM_PARAM_TRIPLE_FAULT_REASON];
> +
>      gdprintk(XENLOG_INFO, "Triple fault on VCPU%d - "
> -             "invoking HVM system reset.\n", v->vcpu_id);
> -    domain_shutdown(v->domain, SHUTDOWN_reboot);
> +             "invoking HVM shutdown action %"PRIu8".\n",
> +             v->vcpu_id, reason);
> +    domain_shutdown(d, reason);
>  }
>  
>  void hvm_inject_trap(struct hvm_trap *trap)
> @@ -3929,6 +3934,10 @@ long do_hvm_op(unsigned long op, XEN_GUE
>              case HVM_PARAM_BUFIOREQ_EVTCHN:
>                  rc = -EINVAL;
>                  break;
> +            case HVM_PARAM_TRIPLE_FAULT_REASON:
> +                if ( a.value > SHUTDOWN_MAX )
> +                    rc = -EINVAL;
> +                break;
>              }
>  
>              if ( rc == 0 )
> diff -r 63594ce1708f -r dc98663be34e xen/include/public/hvm/params.h
> --- a/xen/include/public/hvm/params.h
> +++ b/xen/include/public/hvm/params.h
> @@ -142,6 +142,9 @@
>  #define HVM_PARAM_ACCESS_RING_PFN   28
>  #define HVM_PARAM_SHARING_RING_PFN  29
>  
> -#define HVM_NR_PARAMS          31
> +/* SHUTDOWN_* action in case of a triple fault */
> +#define HVM_PARAM_TRIPLE_FAULT_REASON 31
> +
> +#define HVM_NR_PARAMS          32
>  
>  #endif /* __XEN_PUBLIC_HVM_PARAMS_H__ */
> diff -r 63594ce1708f -r dc98663be34e xen/include/public/sched.h
> --- a/xen/include/public/sched.h
> +++ b/xen/include/public/sched.h
> @@ -158,6 +158,7 @@ DEFINE_XEN_GUEST_HANDLE(sched_watchdog_t
>  #define SHUTDOWN_suspend    2  /* Clean up, save suspend info, kill.
> */
>  #define SHUTDOWN_crash      3  /* Tell controller we've crashed.
> */
>  #define SHUTDOWN_watchdog   4  /* Restart because watchdog time expired.
> */
> +#define SHUTDOWN_MAX        4  /* Maximum valid shutdown reason.
> */
>  /* ` } */
>  
>  #endif /* __XEN_PUBLIC_SCHED_H__ */



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