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: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20200325142906.221248-5-npiggin@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
[dwg: Updated comment at Greg's suggestion]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index c8964eb..1069d01 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -833,13 +833,28 @@
/* get rtas addr from fdt */
rtas_addr = spapr_get_rtas_addr();
if (!rtas_addr) {
- error_report(
+ if (!recovered) {
+ error_report(
"FWNMI: Unable to deliver machine check to guest: rtas_addr not found.");
- qemu_system_guest_panicked(NULL);
+ 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 @@
* that CPU called "ibm,nmi-interlock")
*/
if (spapr->fwnmi_machine_check_interlock == cpu->vcpu_id) {
- error_report(
+ if (!recovered) {
+ error_report(
"FWNMI: Unable to deliver machine check to guest: nested machine check.");
- qemu_system_guest_panicked(NULL);
+ 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 @@
warn_report("Received a fwnmi while migration was in progress");
}
- spapr->fwnmi_machine_check_interlock = cpu->vcpu_id;
spapr_mce_dispatch_elog(cpu, recovered);
}