ppc: spapr: Handle "ibm,nmi-register" and "ibm,nmi-interlock" RTAS calls

This patch adds support in QEMU to handle "ibm,nmi-register"
and "ibm,nmi-interlock" RTAS calls.

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 <arawinda.p@gmail.com>
[Register fwnmi RTAS calls in core_rtas_register_types()
 where other RTAS calls are registered]
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Message-Id: <20200130184423.20519-6-ganeshgr@linux.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 69 insertions, 0 deletions

diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 393ee6845e..8b27d3ac09 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -515,6 +515,16 @@ static void cap_fwnmi_mce_apply(SpaprMachineState *spapr, uint8_t val,
     if (!val) {
         return; /* Disabled by default */
     }
+
+    if (tcg_enabled()) {
+        warn_report("Firmware Assisted Non-Maskable Interrupts(FWNMI) not "
+                    "supported in TCG");
+    } else if (kvm_enabled()) {
+        if (kvmppc_set_fwnmi() < 0) {
+            error_setg(errp, "Firmware Assisted Non-Maskable Interrupts(FWNMI) "
+                             "not supported by KVM");
+        }
+    }
 }
 
 SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 89b7eb6c54..35d91260e6 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -399,6 +399,61 @@ 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;
+
+    if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_OFF) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
+    }
+
+    rtas_addr = spapr_get_rtas_addr();
+    if (!rtas_addr) {
+        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_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_OFF) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
+    }
+
+    if (spapr->guest_machine_check_addr == -1) {
+        /* NMI register not called */
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    if (spapr->mc_status != cpu->vcpu_id) {
+        /* The vCPU that hit the NMI should invoke "ibm,nmi-interlock" */
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    /*
+     * 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;
@@ -527,6 +582,10 @@ static void core_rtas_register_types(void)
                         rtas_set_power_level);
     spapr_rtas_register(RTAS_GET_POWER_LEVEL, "get-power-level",
                         rtas_get_power_level);
+    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);
 }
 
 type_init(core_rtas_register_types)