Commit 4f7a11f9 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by David Gibson
Browse files

ppc/spapr: Don't kill the guest if a recovered FWNMI machine check delivery fails 



Try to be tolerant of FWNMI delivery errors if the machine check had been
recovered by the host.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Message-Id: <20200325142906.221248-5-npiggin@gmail.com>
Reviewed-by: default avatarGreg Kurz <groug@kaod.org>
[dwg: Updated comment at Greg's suggestion]
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent b90b9ecb

hw/ppc/spapr_events.c

+25 −5
Original line number Diff line number Diff line
@@ -833,13 +833,28 @@ static void spapr_mce_dispatch_elog(PowerPCCPU *cpu, bool recovered) 
    /* get rtas addr from fdt */

    rtas_addr = spapr_get_rtas_addr();

    if (!rtas_addr) {

        if (!recovered) {

            error_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;

    }



    /*

     * By taking the interlock, we assume that the MCE will be

     * delivered to the guest. CAUTION: don't add anything that could

     * prevent the MCE to be delivered after this line, otherwise the

     * guest won't be able to release the interlock and ultimately

     * hang/crash?

     */

    spapr->fwnmi_machine_check_interlock = cpu->vcpu_id;



    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 +
@@ -876,9 +891,15 @@ void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered) 
         * that CPU called "ibm,nmi-interlock")

         */

        if (spapr->fwnmi_machine_check_interlock == cpu->vcpu_id) {

            if (!recovered) {

                error_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);
@@ -906,7 +927,6 @@ 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);

}