[PATCH v20 5/7] ppc: spapr: Handle "ibm, nmi-register" and "ibm, nmi-interlock" RTAS calls

[Ganesh Goudar <ganeshgr@linux.ibm.com>]

From: Aravinda Prasad <arawinda.p@gmail.com>

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>
---
 hw/ppc/spapr_caps.c    |  7 +++++
 hw/ppc/spapr_rtas.c    | 59 ++++++++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h |  4 ++-
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 3001098601..c43498da49 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -502,6 +502,13 @@ static void cap_fwnmi_mce_apply(SpaprMachineState *spapr, uint8_t val,
     if (!val) {
         return; /* Disabled by default */
     }
+
+    if (kvm_enabled()) {
+        if (kvmppc_set_fwnmi() < 0) {
+            error_report("Could not enable fwnmi capability");
+            exit(1);
+        }
+    }
 }
 
 SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 2c066a372d..3f162d82f5 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -400,6 +400,61 @@ 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;
@@ -528,6 +583,10 @@ 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)
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 652a5514e8..f6f82d88aa 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -656,8 +656,10 @@ 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
-- 
2.17.2