[Qemu-devel] [patch-for-4.2 PATCH v11 5/6] ppc: spapr: Handle "ibm, nmi-register" and "ibm, nmi-interlock" RTAS calls

[Aravinda Prasad]

This patch adds support in QEMU to handle "ibm,nmi-register"
and "ibm,nmi-interlock" RTAS calls and sets the default
value of SPAPR_CAP_FWNMI_MCE to SPAPR_CAP_ON for machine
type 4.2.

The machine check notification address is saved when the
OS issues "ibm,nmi-register" RTAS call.

This patch also handles the case when multiple processors
experience machine check at or about the same time by
handling "ibm,nmi-interlock" call. In such cases, as per
PAPR, subsequent processors serialize waiting for the first
processor to issue the "ibm,nmi-interlock" call. The second
processor that also received a machine check error waits
till the first processor is done reading the error log.
The first processor issues "ibm,nmi-interlock" call
when the error log is consumed.

Signed-off-by: Aravinda Prasad <address@hidden>
---
 hw/ppc/spapr.c         |   14 ++++++++++++-
 hw/ppc/spapr_rtas.c    |   50 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h |    5 ++++-
 3 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 27ea679..04d7ac6 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2931,6 +2931,15 @@ static void spapr_machine_init(MachineState *machine)
 
         /* Resize rtas blob to accommodate error log */
         spapr->rtas_size = RTAS_ERROR_LOG_MAX;
+
+        /* Set fwnmi capability in KVM */
+        if (kvmppc_set_fwnmi() < 0) {
+            error_report("Could not enable FWNMI capability");
+            exit(1);
+        }
+
+        /* Register ibm,nmi-register and ibm,nmi-interlock RTAS calls */
+        spapr_fwnmi_register();
     }
 
     spapr->rtas_blob = g_malloc(spapr->rtas_size);
@@ -4484,7 +4493,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
void *data)
     smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
     smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
     smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF;
-    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF;
+    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_ON;
     spapr_caps_add_properties(smc, &error_abort);
     smc->irq = &spapr_irq_dual;
     smc->dr_phb_enabled = true;
@@ -4547,6 +4556,8 @@ DEFINE_SPAPR_MACHINE(4_2, "4.2", true);
  */
 static void spapr_machine_4_1_class_options(MachineClass *mc)
 {
+    SpaprMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
+
     static GlobalProperty compat[] = {
         /* Only allow 4kiB and 64kiB IOMMU pagesizes */
         { TYPE_SPAPR_PCI_HOST_BRIDGE, "pgsz", "0x11000" },
@@ -4555,6 +4566,7 @@ static void spapr_machine_4_1_class_options(MachineClass 
*mc)
     spapr_machine_4_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_4_1, hw_compat_4_1_len);
     compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
+    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF;
 }
 
 DEFINE_SPAPR_MACHINE(4_1, "4.1", false);
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index bb650e0..e4639a4 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -384,6 +384,48 @@ static void rtas_get_power_level(PowerPCCPU *cpu, 
SpaprMachineState *spapr,
     rtas_st(rets, 1, 100);
 }
 
+static void rtas_ibm_nmi_register(PowerPCCPU *cpu,
+                                  SpaprMachineState *spapr,
+                                  uint32_t token, uint32_t nargs,
+                                  target_ulong args,
+                                  uint32_t nret, target_ulong rets)
+{
+    hwaddr rtas_addr = spapr_get_rtas_addr();
+
+    if (!rtas_addr) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
+    }
+
+    if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_OFF) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
+    }
+
+    spapr->guest_machine_check_addr = rtas_ld(args, 1);
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+}
+
+static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
+                                   SpaprMachineState *spapr,
+                                   uint32_t token, uint32_t nargs,
+                                   target_ulong args,
+                                   uint32_t nret, target_ulong rets)
+{
+    if (spapr->guest_machine_check_addr == -1) {
+        /* NMI register not called */
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+    } else {
+        /*
+         * vCPU issuing "ibm,nmi-interlock" is done with NMI handling,
+         * hence unset mc_status.
+         */
+        spapr->mc_status = -1;
+        qemu_cond_signal(&spapr->mc_delivery_cond);
+        rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+    }
+}
+
 static struct rtas_call {
     const char *name;
     spapr_rtas_fn fn;
@@ -528,6 +570,14 @@ hwaddr spapr_get_rtas_addr(void)
     return (hwaddr)fdt32_to_cpu(*rtas_data);
 }
 
+void spapr_fwnmi_register(void)
+{
+    spapr_rtas_register(RTAS_IBM_NMI_REGISTER, "ibm,nmi-register",
+                        rtas_ibm_nmi_register);
+    spapr_rtas_register(RTAS_IBM_NMI_INTERLOCK, "ibm,nmi-interlock",
+                        rtas_ibm_nmi_interlock);
+}
+
 static void core_rtas_register_types(void)
 {
     spapr_rtas_register(RTAS_DISPLAY_CHARACTER, "display-character",
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 47f05f2..bc566f9 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -654,8 +654,10 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong 
opcode,
 #define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
 #define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
 #define RTAS_IBM_SUSPEND_ME                     (RTAS_TOKEN_BASE + 0x2A)
+#define RTAS_IBM_NMI_REGISTER                   (RTAS_TOKEN_BASE + 0x2B)
+#define RTAS_IBM_NMI_INTERLOCK                  (RTAS_TOKEN_BASE + 0x2C)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2B)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2D)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
@@ -907,4 +909,5 @@ void spapr_check_pagesize(SpaprMachineState *spapr, hwaddr 
pagesize,
 
 void spapr_set_all_lpcrs(target_ulong value, target_ulong mask);
 hwaddr spapr_get_rtas_addr(void);
+void spapr_fwnmi_register(void);
 #endif /* HW_SPAPR_H */