Re: [PATCH 4/5] ppc/spapr: Don't kill the guest if a recovered FWNMI machine check delivery fails

[Greg Kurz]

On Tue, 17 Mar 2020 15:02:14 +1000
Nicholas Piggin <address@hidden> wrote:

> Try to be tolerant of errors if the machine check had been recovered
> by the host.
> 
> Signed-off-by: Nicholas Piggin <address@hidden>
> ---

Same comment as previous patch on multi-line error strings and
warn_report() in the !recovered case.

>  hw/ppc/spapr_events.c | 25 ++++++++++++++++++-------
>  1 file changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> index d35151eeb0..3f524cb0ca 100644
> --- a/hw/ppc/spapr_events.c
> +++ b/hw/ppc/spapr_events.c
> @@ -807,13 +807,20 @@ static void spapr_mce_dispatch_elog(PowerPCCPU *cpu, 
> bool recovered)
>      /* get rtas addr from fdt */
>      rtas_addr = spapr_get_rtas_addr();
>      if (!rtas_addr) {
> -        warn_report("FWNMI: Unable to deliver machine check to guest: "
> -                    "rtas_addr not found.");
> -        qemu_system_guest_panicked(NULL);
> +        if (!recovered) {
> +            warn_report("FWNMI: Unable to deliver machine check to guest: "
> +                        "rtas_addr not found.");
> +            qemu_system_guest_panicked(NULL);
> +        } else {
> +            warn_report("FWNMI: Unable to deliver machine check to guest: "
> +                        "rtas_addr not found. Machine check recovered.");
> +        }
>          g_free(ext_elog);
>          return;
>      }
>  
> +    spapr->fwnmi_machine_check_interlock = cpu->vcpu_id;
> +

I don't understand this change.

>      stq_be_phys(&address_space_memory, rtas_addr + RTAS_ERROR_LOG_OFFSET,
>                  env->gpr[3]);
>      cpu_physical_memory_write(rtas_addr + RTAS_ERROR_LOG_OFFSET +
> @@ -850,9 +857,14 @@ void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
>           * that CPU called "ibm,nmi-interlock")
>           */
>          if (spapr->fwnmi_machine_check_interlock == cpu->vcpu_id) {
> -            warn_report("FWNMI: Unable to deliver machine check to guest: "
> -                        "nested machine check.");
> -            qemu_system_guest_panicked(NULL);
> +            if (!recovered) {
> +                warn_report("FWNMI: Unable to deliver machine check to 
> guest: "
> +                            "nested machine check.");
> +                qemu_system_guest_panicked(NULL);
> +            } else {
> +                warn_report("FWNMI: Unable to deliver machine check to 
> guest: "
> +                            "nested machine check. Machine check 
> recovered.");
> +            }
>              return;
>          }
>          qemu_cond_wait_iothread(&spapr->fwnmi_machine_check_interlock_cond);
> @@ -880,7 +892,6 @@ void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
>          warn_report("Received a fwnmi while migration was in progress");
>      }
>  
> -    spapr->fwnmi_machine_check_interlock = cpu->vcpu_id;
>      spapr_mce_dispatch_elog(cpu, recovered);
>  }
>