[PATCH 2/2] powerpc/64s: Better printing of machine check info for guest MCEs

[Aravinda Prasad]

On Wednesday 20 February 2019 06:36 AM, Paul Mackerras wrote:
> This adds an "in_guest" parameter to machine_check_print_event_info()
> so that we can avoid trying to translate guest NIP values into
> symbolic form using the host kernel's symbol table.

Reviewed-by: Aravinda Prasad <aravinda at linux.vnet.ibm.com>

Regards,
Aravinda

> 
> Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
> ---
>  arch/powerpc/include/asm/mce.h        | 2 +-
>  arch/powerpc/kernel/mce.c             | 8 +++++---
>  arch/powerpc/kvm/book3s_hv.c          | 4 ++--
>  arch/powerpc/platforms/powernv/opal.c | 2 +-
>  4 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
> index a8b8903..17996bc 100644
> --- a/arch/powerpc/include/asm/mce.h
> +++ b/arch/powerpc/include/asm/mce.h
> @@ -209,7 +209,7 @@ extern int get_mce_event(struct machine_check_event *mce, bool release);
>  extern void release_mce_event(void);
>  extern void machine_check_queue_event(void);
>  extern void machine_check_print_event_info(struct machine_check_event *evt,
> -					   bool user_mode);
> +					   bool user_mode, bool in_guest);
>  #ifdef CONFIG_PPC_BOOK3S_64
>  void flush_and_reload_slb(void);
>  #endif /* CONFIG_PPC_BOOK3S_64 */
> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
> index bd933a7..d01b690 100644
> --- a/arch/powerpc/kernel/mce.c
> +++ b/arch/powerpc/kernel/mce.c
> @@ -301,13 +301,13 @@ static void machine_check_process_queued_event(struct irq_work *work)
>  	while (__this_cpu_read(mce_queue_count) > 0) {
>  		index = __this_cpu_read(mce_queue_count) - 1;
>  		evt = this_cpu_ptr(&mce_event_queue[index]);
> -		machine_check_print_event_info(evt, false);
> +		machine_check_print_event_info(evt, false, false);
>  		__this_cpu_dec(mce_queue_count);
>  	}
>  }
> 
>  void machine_check_print_event_info(struct machine_check_event *evt,
> -				    bool user_mode)
> +				    bool user_mode, bool in_guest)
>  {
>  	const char *level, *sevstr, *subtype;
>  	static const char *mc_ue_types[] = {
> @@ -387,7 +387,9 @@ void machine_check_print_event_info(struct machine_check_event *evt,
>  	       evt->disposition == MCE_DISPOSITION_RECOVERED ?
>  	       "Recovered" : "Not recovered");
> 
> -	if (user_mode) {
> +	if (in_guest) {
> +		printk("%s  Guest NIP: %016llx\n", evt->srr0);
> +	} else if (user_mode) {
>  		printk("%s  NIP: [%016llx] PID: %d Comm: %s\n", level,
>  			evt->srr0, current->pid, current->comm);
>  	} else {
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index d8bf05a..81cba4b 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -1216,7 +1216,7 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu,
>  		break;
>  	case BOOK3S_INTERRUPT_MACHINE_CHECK:
>  		/* Print the MCE event to host console. */
> -		machine_check_print_event_info(&vcpu->arch.mce_evt, false);
> +		machine_check_print_event_info(&vcpu->arch.mce_evt, false, true);
> 
>  		/*
>  		 * If the guest can do FWNMI, exit to userspace so it can
> @@ -1406,7 +1406,7 @@ static int kvmppc_handle_nested_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
>  		/* Pass the machine check to the L1 guest */
>  		r = RESUME_HOST;
>  		/* Print the MCE event to host console. */
> -		machine_check_print_event_info(&vcpu->arch.mce_evt, false);
> +		machine_check_print_event_info(&vcpu->arch.mce_evt, false, true);
>  		break;
>  	/*
>  	 * We get these next two if the guest accesses a page which it thinks
> diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
> index 79586f1..05c85be 100644
> --- a/arch/powerpc/platforms/powernv/opal.c
> +++ b/arch/powerpc/platforms/powernv/opal.c
> @@ -587,7 +587,7 @@ int opal_machine_check(struct pt_regs *regs)
>  		       evt.version);
>  		return 0;
>  	}
> -	machine_check_print_event_info(&evt, user_mode(regs));
> +	machine_check_print_event_info(&evt, user_mode(regs), false);
> 
>  	if (opal_recover_mce(regs, &evt))
>  		return 1;
> 

-- 
Regards,
Aravinda