[Qemu-devel] [PATCH v4 09/17] spapr_events: event-scan RTAS interface

[Michael Roth <mdroth@linux.vnet.ibm.com>]

From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>

We don't actually rely on this interface to surface hotplug events, and
instead rely on the similar-but-interrupt-driven check-exception RTAS
interface used for EPOW events. However, the existence of this interface
is needed to ensure guest kernels initialize the event-reporting
interfaces which will in turn be used by userspace tools to handle these
events, so we implement this interface as a stub.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c         | 1 +
 hw/ppc/spapr_events.c  | 9 +++++++++
 include/hw/ppc/spapr.h | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 1bc5773..a611616 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -541,6 +541,7 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
         refpoints, sizeof(refpoints))));
 
     _FDT((fdt_property_cell(fdt, "rtas-error-log-max", RTAS_ERROR_LOG_MAX)));
+    _FDT((fdt_property_cell(fdt, "rtas-event-scan-rate", RTAS_EVENT_SCAN_RATE)));
 
     /*
      * According to PAPR, rtas ibm,os-term does not guarantee a return
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index ebbf3a4..434a75d 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -445,6 +445,14 @@ static void check_exception(PowerPCCPU *cpu, sPAPREnvironment *spapr,
     }
 }
 
+static void event_scan(PowerPCCPU *cpu, sPAPREnvironment *spapr,
+                            uint32_t token, uint32_t nargs,
+                            target_ulong args,
+                            uint32_t nret, target_ulong rets)
+{
+    rtas_st(rets, 0, 1); /* no error events found */
+}
+
 void spapr_events_init(sPAPREnvironment *spapr)
 {
     spapr->check_exception_irq = xics_alloc(spapr->icp, 0, 0, false);
@@ -452,4 +460,5 @@ void spapr_events_init(sPAPREnvironment *spapr)
     qemu_register_powerdown_notifier(&spapr->epow_notifier);
     spapr_rtas_register(RTAS_CHECK_EXCEPTION, "check-exception",
                         check_exception);
+    spapr_rtas_register(RTAS_EVENT_SCAN, "event-scan", event_scan);
 }
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 4d50e74..973193d 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -453,6 +453,8 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
 
 #define RTAS_ERROR_LOG_MAX      2048
 
+#define RTAS_EVENT_SCAN_RATE    1
+
 typedef struct sPAPRTCETable sPAPRTCETable;
 
 #define TYPE_SPAPR_TCE_TABLE "spapr-tce-table"
-- 
1.9.1