[Qemu-devel] [PATCH v9 1/6] 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.

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. This patch implements the
releasing part of the error-log while subsequent patch
(which builds error log) handles the locking part.

Signed-off-by: Aravinda Prasad <address@hidden>
Reviewed-by: David Gibson <address@hidden>
---
 hw/ppc/spapr.c         |    7 +++++
 hw/ppc/spapr_rtas.c    |   65 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h |    9 ++++++-
 3 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e2b33e5..fae28a9 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1808,6 +1808,11 @@ static void spapr_machine_reset(void)
     first_ppc_cpu->env.gpr[5] = 0;
 
     spapr->cas_reboot = false;
+
+    spapr->guest_machine_check_addr = -1;
+
+    /* Signal all vCPUs waiting on this condition */
+    qemu_cond_broadcast(&spapr->mc_delivery_cond);
 }
 
 static void spapr_create_nvram(SpaprMachineState *spapr)
@@ -3072,6 +3077,8 @@ static void spapr_machine_init(MachineState *machine)
 
         kvmppc_spapr_enable_inkernel_multitce();
     }
+
+    qemu_cond_init(&spapr->mc_delivery_cond);
 }
 
 static int spapr_kvm_type(MachineState *machine, const char *vm_type)
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 5bc1a93..e7509cf 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -352,6 +352,38 @@ 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;
+    }
+
+    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 {
+        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;
@@ -470,6 +502,35 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, 
hwaddr addr)
     }
 }
 
+hwaddr spapr_get_rtas_addr(void)
+{
+    SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
+    int rtas_node;
+    const struct fdt_property *rtas_addr_prop;
+    void *fdt = spapr->fdt_blob;
+    uint32_t rtas_addr;
+
+    /* fetch rtas addr from fdt */
+    rtas_node = fdt_path_offset(fdt, "/rtas");
+    if (rtas_node == 0) {
+        return 0;
+    }
+
+    rtas_addr_prop = fdt_get_property(fdt, rtas_node, "linux,rtas-base", NULL);
+    if (!rtas_addr_prop) {
+        return 0;
+    }
+
+    /*
+     * We assume that the OS called RTAS instantiate-rtas, but some other
+     * OS might call RTAS instantiate-rtas-64 instead. This fine as of now
+     * as SLOF only supports 32-bit variant.
+     */
+    rtas_addr = fdt32_to_cpu(*(uint32_t *)rtas_addr_prop->data);
+    return (hwaddr)rtas_addr;
+}
+
+
 static void core_rtas_register_types(void)
 {
     spapr_rtas_register(RTAS_DISPLAY_CHARACTER, "display-character",
@@ -493,6 +554,10 @@ 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 4f5becf..9dc5e30 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -188,6 +188,10 @@ struct SpaprMachineState {
      * occurs during the unplug process. */
     QTAILQ_HEAD(, SpaprDimmState) pending_dimm_unplugs;
 
+    /* State related to "ibm,nmi-register" and "ibm,nmi-interlock" calls */
+    target_ulong guest_machine_check_addr;
+    QemuCond mc_delivery_cond;
+
     /*< public >*/
     char *kvm_type;
     char *host_model;
@@ -624,8 +628,10 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong 
opcode,
 #define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
 #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_NMI_REGISTER                   (RTAS_TOKEN_BASE + 0x2A)
+#define RTAS_IBM_NMI_INTERLOCK                  (RTAS_TOKEN_BASE + 0x2B)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2C)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
@@ -876,4 +882,5 @@ void spapr_check_pagesize(SpaprMachineState *spapr, hwaddr 
pagesize,
 #define SPAPR_OV5_XIVE_BOTH     0x80 /* Only to advertise on the platform */
 
 void spapr_set_all_lpcrs(target_ulong value, target_ulong mask);
+uint64_t spapr_get_rtas_addr(void);
 #endif /* HW_SPAPR_H */