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

Pierre Morel
2022-10-12T16:21:40Z

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