[PATCH v10 2/9] s390x/cpu topology: reporting the CPU topology to the guest

[Pierre Morel]

The guest can use the STSI instruction to get a buffer filled
with the CPU topology description.

Let us implement the STSI instruction for the basis CPU topology
level, level 2.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 include/hw/s390x/cpu-topology.h |   3 +
 target/s390x/cpu.h              |  48 ++++++++++++++
 hw/s390x/cpu-topology.c         |   8 ++-
 target/s390x/cpu_topology.c     | 109 ++++++++++++++++++++++++++++++++
 target/s390x/kvm/kvm.c          |   6 +-
 target/s390x/meson.build        |   1 +
 6 files changed, 172 insertions(+), 3 deletions(-)
 create mode 100644 target/s390x/cpu_topology.c

diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
index 66c171d0bc..61c11db017 100644
--- a/include/hw/s390x/cpu-topology.h
+++ b/include/hw/s390x/cpu-topology.h
@@ -13,6 +13,8 @@
 #include "hw/qdev-core.h"
 #include "qom/object.h"
 
+#define S390_TOPOLOGY_POLARITY_H  0x00
+
 typedef struct S390TopoContainer {
     int active_count;
 } S390TopoContainer;
@@ -29,6 +31,7 @@ struct S390Topology {
     S390TopoContainer *socket;
     S390TopoTLE *tle;
     MachineState *ms;
+    QemuMutex topo_mutex;
 };
 
 #define TYPE_S390_CPU_TOPOLOGY "s390-topology"
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 7d6d01325b..d604aa9c78 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -565,6 +565,52 @@ typedef union SysIB {
 } SysIB;
 QEMU_BUILD_BUG_ON(sizeof(SysIB) != 4096);
 
+/* CPU type Topology List Entry */
+typedef struct SysIBTl_cpu {
+        uint8_t nl;
+        uint8_t reserved0[3];
+        uint8_t reserved1:5;
+        uint8_t dedicated:1;
+        uint8_t polarity:2;
+        uint8_t type;
+        uint16_t origin;
+        uint64_t mask;
+} QEMU_PACKED QEMU_ALIGNED(8) SysIBTl_cpu;
+QEMU_BUILD_BUG_ON(sizeof(SysIBTl_cpu) != 16);
+
+/* Container type Topology List Entry */
+typedef struct SysIBTl_container {
+        uint8_t nl;
+        uint8_t reserved[6];
+        uint8_t id;
+} QEMU_PACKED QEMU_ALIGNED(8) SysIBTl_container;
+QEMU_BUILD_BUG_ON(sizeof(SysIBTl_container) != 8);
+
+#define TOPOLOGY_NR_MAG  6
+#define TOPOLOGY_NR_MAG6 0
+#define TOPOLOGY_NR_MAG5 1
+#define TOPOLOGY_NR_MAG4 2
+#define TOPOLOGY_NR_MAG3 3
+#define TOPOLOGY_NR_MAG2 4
+#define TOPOLOGY_NR_MAG1 5
+/* Configuration topology */
+typedef struct SysIB_151x {
+    uint8_t  reserved0[2];
+    uint16_t length;
+    uint8_t  mag[TOPOLOGY_NR_MAG];
+    uint8_t  reserved1;
+    uint8_t  mnest;
+    uint32_t reserved2;
+    char tle[0];
+} QEMU_PACKED QEMU_ALIGNED(8) SysIB_151x;
+QEMU_BUILD_BUG_ON(sizeof(SysIB_151x) != 16);
+
+/* Maxi size of a SYSIB structure is when all CPU are alone in a container */
+#define S390_TOPOLOGY_SYSIB_SIZE (sizeof(SysIB_151x) +                         
\
+                                  S390_MAX_CPUS * (sizeof(SysIBTl_container) + 
\
+                                                   sizeof(SysIBTl_cpu)))
+
+
 /* MMU defines */
 #define ASCE_ORIGIN           (~0xfffULL) /* segment table origin             
*/
 #define ASCE_SUBSPACE         0x200       /* subspace group control           
*/
@@ -843,4 +889,6 @@ S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
 
 #include "exec/cpu-all.h"
 
+void insert_stsi_15_1_x(S390CPU *cpu, int sel2, __u64 addr, uint8_t ar);
+
 #endif
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index 42b22a1831..c73cebfe6f 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -54,8 +54,6 @@ void s390_topology_new_cpu(int core_id)
         return;
     }
 
-    socket_id = core_id / topo->cpus;
-
     /*
      * At the core level, each CPU is represented by a bit in a 64bit
      * unsigned long which represent the presence of a CPU.
@@ -76,8 +74,13 @@ void s390_topology_new_cpu(int core_id)
     bit %= 64;
     bit = 63 - bit;
 
+    qemu_mutex_lock(&topo->topo_mutex);
+
+    socket_id = core_id / topo->cpus;
     topo->socket[socket_id].active_count++;
     set_bit(bit, &topo->tle[socket_id].mask[origin]);
+
+    qemu_mutex_unlock(&topo->topo_mutex);
 }
 
 /**
@@ -101,6 +104,7 @@ static void s390_topology_realize(DeviceState *dev, Error 
**errp)
     topo->tle = g_new0(S390TopoTLE, ms->smp.max_cpus);
 
     topo->ms = ms;
+    qemu_mutex_init(&topo->topo_mutex);
 }
 
 /**
diff --git a/target/s390x/cpu_topology.c b/target/s390x/cpu_topology.c
new file mode 100644
index 0000000000..df86a98f23
--- /dev/null
+++ b/target/s390x/cpu_topology.c
@@ -0,0 +1,109 @@
+/*
+ * QEMU S390x CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ * Author(s): Pierre Morel <pmorel@linux.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "hw/s390x/pv.h"
+#include "hw/sysbus.h"
+#include "hw/s390x/cpu-topology.h"
+#include "hw/s390x/sclp.h"
+
+#define S390_TOPOLOGY_MAX_STSI_SIZE (S390_MAX_CPUS *              \
+                                     (sizeof(SysIB_151x) +        \
+                                      sizeof(SysIBTl_container) + \
+                                      sizeof(SysIBTl_cpu)))
+
+static char *fill_container(char *p, int level, int id)
+{
+    SysIBTl_container *tle = (SysIBTl_container *)p;
+
+    tle->nl = level;
+    tle->id = id;
+    return p + sizeof(*tle);
+}
+
+static char *fill_tle_cpu(char *p, uint64_t mask, int origin)
+{
+    SysIBTl_cpu *tle = (SysIBTl_cpu *)p;
+
+    tle->nl = 0;
+    tle->dedicated = 1;
+    tle->polarity = S390_TOPOLOGY_POLARITY_H;
+    tle->type = S390_TOPOLOGY_CPU_IFL;
+    tle->origin = cpu_to_be64(origin * 64);
+    tle->mask = cpu_to_be64(mask);
+    return p + sizeof(*tle);
+}
+
+static char *s390_top_set_level2(S390Topology *topo, char *p)
+{
+    MachineState *ms = topo->ms;
+    int i, origin;
+
+    for (i = 0; i < ms->smp.sockets; i++) {
+        if (!topo->socket[i].active_count) {
+            continue;
+        }
+        p = fill_container(p, 1, i);
+        for (origin = 0; origin < S390_TOPOLOGY_MAX_ORIGIN; origin++) {
+            uint64_t mask = 0L;
+
+            mask = topo->tle[i].mask[origin];
+            if (mask) {
+                p = fill_tle_cpu(p, mask, origin);
+            }
+        }
+    }
+    return p;
+}
+
+static int setup_stsi(SysIB_151x *sysib, int level)
+{
+    S390Topology *topo = s390_get_topology();
+    MachineState *ms = topo->ms;
+    char *p = sysib->tle;
+
+    qemu_mutex_lock(&topo->topo_mutex);
+
+    sysib->mnest = level;
+    switch (level) {
+    case 2:
+        sysib->mag[TOPOLOGY_NR_MAG2] = ms->smp.sockets;
+        sysib->mag[TOPOLOGY_NR_MAG1] = topo->cpus;
+        p = s390_top_set_level2(topo, p);
+        break;
+    }
+
+    qemu_mutex_unlock(&topo->topo_mutex);
+
+    return p - (char *) sysib;
+}
+
+#define S390_TOPOLOGY_MAX_MNEST 2
+
+void insert_stsi_15_1_x(S390CPU *cpu, int sel2, __u64 addr, uint8_t ar)
+{
+    uint64_t page[S390_TOPOLOGY_SYSIB_SIZE / sizeof(uint64_t)] = {};
+    SysIB_151x *sysib = (SysIB_151x *) page;
+    int len;
+
+    if (s390_is_pv() || !s390_has_topology() ||
+        sel2 < 2 || sel2 > S390_TOPOLOGY_MAX_MNEST) {
+        setcc(cpu, 3);
+        return;
+    }
+
+    len = setup_stsi(sysib, sel2);
+
+    sysib->length = cpu_to_be16(len);
+    s390_cpu_virt_mem_write(cpu, addr, ar, sysib, len);
+    setcc(cpu, 0);
+}
+
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index 6a8dbadf7e..f96630440b 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -51,6 +51,7 @@
 #include "hw/s390x/s390-virtio-ccw.h"
 #include "hw/s390x/s390-virtio-hcall.h"
 #include "hw/s390x/pv.h"
+#include "hw/s390x/cpu-topology.h"
 
 #ifndef DEBUG_KVM
 #define DEBUG_KVM  0
@@ -1917,9 +1918,12 @@ static int handle_stsi(S390CPU *cpu)
         if (run->s390_stsi.sel1 != 2 || run->s390_stsi.sel2 != 2) {
             return 0;
         }
-        /* Only sysib 3.2.2 needs post-handling for now. */
         insert_stsi_3_2_2(cpu, run->s390_stsi.addr, run->s390_stsi.ar);
         return 0;
+    case 15:
+        insert_stsi_15_1_x(cpu, run->s390_stsi.sel2, run->s390_stsi.addr,
+                           run->s390_stsi.ar);
+        return 0;
     default:
         return 0;
     }
diff --git a/target/s390x/meson.build b/target/s390x/meson.build
index 84c1402a6a..890ccfa789 100644
--- a/target/s390x/meson.build
+++ b/target/s390x/meson.build
@@ -29,6 +29,7 @@ s390x_softmmu_ss.add(files(
   'sigp.c',
   'cpu-sysemu.c',
   'cpu_models_sysemu.c',
+  'cpu_topology.c',
 ))
 
 s390x_user_ss = ss.source_set()
-- 
2.31.1