[Qemu-devel] [PATCH v12 4/6] target/ppc: Build rtas error log upon an MCE

[Aravinda Prasad]

Upon a machine check exception (MCE) in a guest address space,
KVM causes a guest exit to enable QEMU to build and pass the
error to the guest in the PAPR defined rtas error log format.

This patch builds the rtas error log, copies it to the rtas_addr
and then invokes the guest registered machine check handler. The
handler in the guest takes suitable action(s) depending on the type
and criticality of the error. For example, if an error is
unrecoverable memory corruption in an application inside the
guest, then the guest kernel sends a SIGBUS to the application.
For recoverable errors, the guest performs recovery actions and
logs the error.

Signed-off-by: Aravinda Prasad <address@hidden>
---
 hw/ppc/spapr.c         |   13 +++
 hw/ppc/spapr_events.c  |  233 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_rtas.c    |   26 +++++
 include/hw/ppc/spapr.h |    6 +
 target/ppc/kvm.c       |    4 +
 5 files changed, 279 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 76ed988..9f2e5d2 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2930,6 +2930,19 @@ static void spapr_machine_init(MachineState *machine)
         error_report("Could not get size of LPAR rtas '%s'", filename);
         exit(1);
     }
+
+    if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_ON) {
+        /*
+         * Ensure that the rtas image size is less than RTAS_ERROR_LOG_OFFSET
+         * or else the rtas image will be overwritten with the rtas error log
+         * when a machine check exception is encountered.
+         */
+        g_assert(spapr->rtas_size < RTAS_ERROR_LOG_OFFSET);
+
+        /* Resize rtas blob to accommodate error log */
+        spapr->rtas_size = RTAS_ERROR_LOG_MAX;
+    }
+
     spapr->rtas_blob = g_malloc(spapr->rtas_size);
     if (load_image_size(filename, spapr->rtas_blob, spapr->rtas_size) < 0) {
         error_report("Could not load LPAR rtas '%s'", filename);
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index e76c1a7..8ebb85e 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -214,6 +214,106 @@ struct hp_extended_log {
     struct rtas_event_log_v6_hp hp;
 } QEMU_PACKED;
 
+struct rtas_event_log_v6_mc {
+#define RTAS_LOG_V6_SECTION_ID_MC                   0x4D43 /* MC */
+    struct rtas_event_log_v6_section_header hdr;
+    uint32_t fru_id;
+    uint32_t proc_id;
+    uint8_t error_type;
+#define RTAS_LOG_V6_MC_TYPE_UE                           0
+#define RTAS_LOG_V6_MC_TYPE_SLB                          1
+#define RTAS_LOG_V6_MC_TYPE_ERAT                         2
+#define RTAS_LOG_V6_MC_TYPE_TLB                          4
+#define RTAS_LOG_V6_MC_TYPE_D_CACHE                      5
+#define RTAS_LOG_V6_MC_TYPE_I_CACHE                      7
+    uint8_t sub_err_type;
+#define RTAS_LOG_V6_MC_UE_INDETERMINATE                  0
+#define RTAS_LOG_V6_MC_UE_IFETCH                         1
+#define RTAS_LOG_V6_MC_UE_PAGE_TABLE_WALK_IFETCH         2
+#define RTAS_LOG_V6_MC_UE_LOAD_STORE                     3
+#define RTAS_LOG_V6_MC_UE_PAGE_TABLE_WALK_LOAD_STORE     4
+#define RTAS_LOG_V6_MC_SLB_PARITY                        0
+#define RTAS_LOG_V6_MC_SLB_MULTIHIT                      1
+#define RTAS_LOG_V6_MC_SLB_INDETERMINATE                 2
+#define RTAS_LOG_V6_MC_ERAT_PARITY                       1
+#define RTAS_LOG_V6_MC_ERAT_MULTIHIT                     2
+#define RTAS_LOG_V6_MC_ERAT_INDETERMINATE                3
+#define RTAS_LOG_V6_MC_TLB_PARITY                        1
+#define RTAS_LOG_V6_MC_TLB_MULTIHIT                      2
+#define RTAS_LOG_V6_MC_TLB_INDETERMINATE                 3
+    uint8_t reserved_1[6];
+    uint64_t effective_address;
+    uint64_t logical_address;
+} QEMU_PACKED;
+
+struct mc_extended_log {
+    struct rtas_event_log_v6 v6hdr;
+    struct rtas_event_log_v6_mc mc;
+} QEMU_PACKED;
+
+struct MC_ierror_table {
+    unsigned long srr1_mask;
+    unsigned long srr1_value;
+    bool nip_valid; /* nip is a valid indicator of faulting address */
+    uint8_t error_type;
+    uint8_t error_subtype;
+    unsigned int initiator;
+    unsigned int severity;
+};
+
+static const struct MC_ierror_table mc_ierror_table[] = {
+{ 0x00000000081c0000, 0x0000000000040000, true,
+  RTAS_LOG_V6_MC_TYPE_UE, RTAS_LOG_V6_MC_UE_IFETCH,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000000081c0000, 0x0000000000080000, true,
+  RTAS_LOG_V6_MC_TYPE_SLB, RTAS_LOG_V6_MC_SLB_PARITY,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000000081c0000, 0x00000000000c0000, true,
+  RTAS_LOG_V6_MC_TYPE_SLB, RTAS_LOG_V6_MC_SLB_MULTIHIT,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000000081c0000, 0x0000000000100000, true,
+  RTAS_LOG_V6_MC_TYPE_ERAT, RTAS_LOG_V6_MC_ERAT_MULTIHIT,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000000081c0000, 0x0000000000140000, true,
+  RTAS_LOG_V6_MC_TYPE_TLB, RTAS_LOG_V6_MC_TLB_MULTIHIT,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000000081c0000, 0x0000000000180000, true,
+  RTAS_LOG_V6_MC_TYPE_UE, RTAS_LOG_V6_MC_UE_PAGE_TABLE_WALK_IFETCH,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0, 0, 0, 0, 0, 0 } };
+
+struct MC_derror_table {
+    unsigned long dsisr_value;
+    bool dar_valid; /* dar is a valid indicator of faulting address */
+    uint8_t error_type;
+    uint8_t error_subtype;
+    unsigned int initiator;
+    unsigned int severity;
+};
+
+static const struct MC_derror_table mc_derror_table[] = {
+{ 0x00008000, false,
+  RTAS_LOG_V6_MC_TYPE_UE, RTAS_LOG_V6_MC_UE_LOAD_STORE,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00004000, true,
+  RTAS_LOG_V6_MC_TYPE_UE, RTAS_LOG_V6_MC_UE_PAGE_TABLE_WALK_LOAD_STORE,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000800, true,
+  RTAS_LOG_V6_MC_TYPE_ERAT, RTAS_LOG_V6_MC_ERAT_MULTIHIT,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000400, true,
+  RTAS_LOG_V6_MC_TYPE_TLB, RTAS_LOG_V6_MC_TLB_MULTIHIT,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000080, true,
+  RTAS_LOG_V6_MC_TYPE_SLB, RTAS_LOG_V6_MC_SLB_MULTIHIT,  /* Before PARITY */
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0x00000100, true,
+  RTAS_LOG_V6_MC_TYPE_SLB, RTAS_LOG_V6_MC_SLB_PARITY,
+  RTAS_LOG_INITIATOR_CPU, RTAS_LOG_SEVERITY_ERROR_SYNC, },
+{ 0, false, 0, 0, 0, 0 } };
+
+#define SRR1_MC_LOADSTORE(srr1) ((srr1) & PPC_BIT(42))
+
 typedef enum EventClass {
     EVENT_CLASS_INTERNAL_ERRORS     = 0,
     EVENT_CLASS_EPOW                = 1,
@@ -622,7 +722,136 @@ void 
spapr_hotplug_req_remove_by_count_indexed(SpaprDrcType drc_type,
                             RTAS_LOG_V6_HP_ACTION_REMOVE, drc_type, &drc_id);
 }
 
-void spapr_mce_req_event(PowerPCCPU *cpu)
+static uint32_t spapr_mce_get_elog_type(PowerPCCPU *cpu, bool recovered,
+                                        struct mc_extended_log *ext_elog)
+{
+    int i;
+    CPUPPCState *env = &cpu->env;
+    uint32_t summary;
+    uint64_t dsisr = env->spr[SPR_DSISR];
+
+    summary = RTAS_LOG_VERSION_6 | RTAS_LOG_OPTIONAL_PART_PRESENT;
+    if (recovered) {
+        summary |= RTAS_LOG_DISPOSITION_FULLY_RECOVERED;
+    } else {
+        summary |= RTAS_LOG_DISPOSITION_NOT_RECOVERED;
+    }
+
+    if (SRR1_MC_LOADSTORE(env->spr[SPR_SRR1])) {
+        for (i = 0; mc_derror_table[i].dsisr_value; i++) {
+            if (!(dsisr & mc_derror_table[i].dsisr_value)) {
+                continue;
+            }
+
+            ext_elog->mc.error_type = mc_derror_table[i].error_type;
+            ext_elog->mc.sub_err_type = mc_derror_table[i].error_subtype;
+            if (mc_derror_table[i].dar_valid) {
+                ext_elog->mc.effective_address = 
cpu_to_be64(env->spr[SPR_DAR]);
+            }
+
+            summary |= mc_derror_table[i].initiator
+                        | mc_derror_table[i].severity;
+
+            return summary;
+        }
+    } else {
+        for (i = 0; mc_ierror_table[i].srr1_mask; i++) {
+            if ((env->spr[SPR_SRR1] & mc_ierror_table[i].srr1_mask) !=
+                    mc_ierror_table[i].srr1_value) {
+                continue;
+            }
+
+            ext_elog->mc.error_type = mc_ierror_table[i].error_type;
+            ext_elog->mc.sub_err_type = mc_ierror_table[i].error_subtype;
+            if (mc_ierror_table[i].nip_valid) {
+                ext_elog->mc.effective_address = cpu_to_be64(env->nip);
+            }
+
+            summary |= mc_ierror_table[i].initiator
+                        | mc_ierror_table[i].severity;
+
+            return summary;
+        }
+    }
+
+    summary |= RTAS_LOG_INITIATOR_CPU;
+    return summary;
+}
+
+static void spapr_mce_dispatch_elog(PowerPCCPU *cpu, bool recovered)
+{
+    SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
+    CPUState *cs = CPU(cpu);
+    uint64_t rtas_addr;
+    CPUPPCState *env = &cpu->env;
+    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
+    target_ulong msr = 0;
+    struct rtas_error_log log;
+    struct mc_extended_log *ext_elog;
+    uint32_t summary;
+
+    /*
+     * Properly set bits in MSR before we invoke the handler.
+     * SRR0/1, DAR and DSISR are properly set by KVM
+     */
+    if (!(*pcc->interrupts_big_endian)(cpu)) {
+        msr |= (1ULL << MSR_LE);
+    }
+
+    if (env->msr & (1ULL << MSR_SF)) {
+        msr |= (1ULL << MSR_SF);
+    }
+
+    msr |= (1ULL << MSR_ME);
+
+    if (spapr->guest_machine_check_addr == -1) {
+        /*
+         * This implies that we have hit a machine check between system
+         * reset and "ibm,nmi-register". Fall back to the old machine
+         * check behavior in such cases.
+         */
+        cs->exception_index = POWERPC_EXCP_MCHECK;
+        ppc_cpu_do_interrupt(cs);
+        return;
+    }
+
+    ext_elog = g_malloc0(sizeof(*ext_elog));
+    summary = spapr_mce_get_elog_type(cpu, recovered, ext_elog);
+
+    log.summary = cpu_to_be32(summary);
+    log.extended_length = cpu_to_be32(sizeof(*ext_elog));
+
+    spapr_init_v6hdr(&ext_elog->v6hdr);
+    ext_elog->mc.hdr.section_id = cpu_to_be16(RTAS_LOG_V6_SECTION_ID_MC);
+    ext_elog->mc.hdr.section_length =
+                    cpu_to_be16(sizeof(struct rtas_event_log_v6_mc));
+    ext_elog->mc.hdr.section_version = 1;
+
+    /* get rtas addr from fdt */
+    rtas_addr = spapr_get_rtas_addr();
+    if (!rtas_addr) {
+        /* Unable to fetch rtas_addr. Hence reset the guest */
+        ppc_cpu_do_system_reset(cs);
+        g_free(ext_elog);
+        return;
+    }
+
+    stq_be_phys(&address_space_memory, rtas_addr + RTAS_ERROR_LOG_OFFSET,
+                env->gpr[3]);
+    cpu_physical_memory_write(rtas_addr + RTAS_ERROR_LOG_OFFSET +
+                              sizeof(env->gpr[3]), &log, sizeof(log));
+    cpu_physical_memory_write(rtas_addr + RTAS_ERROR_LOG_OFFSET +
+                              sizeof(env->gpr[3]) + sizeof(log), ext_elog,
+                              sizeof(*ext_elog));
+
+    env->gpr[3] = rtas_addr + RTAS_ERROR_LOG_OFFSET;
+    env->msr = msr;
+    env->nip = spapr->guest_machine_check_addr;
+
+    g_free(ext_elog);
+}
+
+void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
 {
     SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
 
@@ -643,6 +872,8 @@ void spapr_mce_req_event(PowerPCCPU *cpu)
         }
     }
     spapr->mc_status = cpu->vcpu_id;
+
+    spapr_mce_dispatch_elog(cpu, recovered);
 }
 
 static void check_exception(PowerPCCPU *cpu, SpaprMachineState *spapr,
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index bee3835..d8fb8a8 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -518,6 +518,32 @@ 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 fdt32_t *rtas_data;
+    void *fdt = spapr->fdt_blob;
+
+    /* fetch rtas addr from fdt */
+    rtas_node = fdt_path_offset(fdt, "/rtas");
+    if (rtas_node < 0) {
+        return 0;
+    }
+
+    rtas_data = fdt_getprop(fdt, rtas_node, "linux,rtas-base", NULL);
+    if (!rtas_data) {
+        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.
+     */
+    return (hwaddr)fdt32_to_cpu(*rtas_data);
+}
+
 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 99a2966..ffefde7 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -726,6 +726,9 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, 
hwaddr addr);
 
 #define RTAS_ERROR_LOG_MAX      2048
 
+/* Offset from rtas-base where error log is placed */
+#define RTAS_ERROR_LOG_OFFSET       0x30
+
 #define RTAS_EVENT_SCAN_RATE    1
 
 /* This helper should be used to encode interrupt specifiers when the related
@@ -814,7 +817,7 @@ void spapr_clear_pending_events(SpaprMachineState *spapr);
 int spapr_max_server_number(SpaprMachineState *spapr);
 void spapr_store_hpte(PowerPCCPU *cpu, hwaddr ptex,
                       uint64_t pte0, uint64_t pte1);
-void spapr_mce_req_event(PowerPCCPU *cpu);
+void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered);
 
 /* DRC callbacks. */
 void spapr_core_release(DeviceState *dev);
@@ -904,4 +907,5 @@ 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);
+hwaddr spapr_get_rtas_addr(void);
 #endif /* HW_SPAPR_H */
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 4e282f6..68080b9 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2814,9 +2814,11 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 
 int kvm_handle_nmi(PowerPCCPU *cpu, struct kvm_run *run)
 {
+    bool recovered = run->flags & KVM_RUN_PPC_NMI_DISP_FULLY_RECOV;
+
     cpu_synchronize_state(CPU(cpu));
 
-    spapr_mce_req_event(cpu);
+    spapr_mce_req_event(cpu, recovered);
 
     return 0;
 }