[RFC PATCH 08/13] ppc/spapr: Add FWNMI machine check delivery warnings

[Nicholas Piggin]

Add some messages which explain problems and guest misbehaviour that
may be difficult to diagnose in rare cases of machine checks.

Signed-off-by: Nicholas Piggin <address@hidden>
---
 hw/ppc/spapr_events.c | 4 ++++
 hw/ppc/spapr_rtas.c   | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index ae86629e1f..89ee036dd1 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -807,6 +807,8 @@ 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);
         g_free(ext_elog);
         return;
@@ -848,6 +850,8 @@ 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);
             return;
         }
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 2315505181..6922a6b880 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -455,12 +455,20 @@ static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
     }
 
     if (spapr->fwnmi_machine_check_addr == -1) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "FWNMI: ibm,nmi-interlock RTAS called with FWNMI not "
+                       "registered.\n");
+
         /* NMI register not called */
         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
         return;
     }
 
     if (spapr->fwnmi_machine_check_interlock != cpu->vcpu_id) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "FWNMI: ibm,nmi-interlock RTAS called from CPU not "
+                      "handling a machine check.\n");
+
         /* The vCPU that hit the NMI should invoke "ibm,nmi-interlock" */
         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
         return;
-- 
2.23.0