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-rw-r--r--MAINTAINERS6
-rw-r--r--hw/s390x/cpu-topology.c259
-rw-r--r--hw/s390x/meson.build1
-rw-r--r--hw/s390x/s390-virtio-ccw.c22
-rw-r--r--include/hw/s390x/cpu-topology.h54
5 files changed, 340 insertions, 2 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index 2bf3399b3b..8e2e828f7c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1710,6 +1710,12 @@ F: hw/s390x/event-facility.c
 F: hw/s390x/sclp*.c
 L: qemu-s390x@nongnu.org
 
+S390 CPU topology
+M: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
+S: Supported
+F: include/hw/s390x/cpu-topology.h
+F: hw/s390x/cpu-topology.c
+
 X86 Machines
 ------------
 PC
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
new file mode 100644
index 0000000000..cabd42e779
--- /dev/null
+++ b/hw/s390x/cpu-topology.c
@@ -0,0 +1,259 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022, 2023
+ * Author(s): Pierre Morel <pmorel@linux.ibm.com>
+ *
+ * S390 topology handling can be divided in two parts:
+ *
+ * - The first part in this file is taking care of all common functions
+ *   used by KVM and TCG to create and modify the topology.
+ *
+ * - The second part, building the topology information data for the
+ *   guest with CPU and KVM specificity will be implemented inside
+ *   the target/s390/kvm sub tree.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "hw/boards.h"
+#include "target/s390x/cpu.h"
+#include "hw/s390x/s390-virtio-ccw.h"
+#include "hw/s390x/cpu-topology.h"
+
+/*
+ * s390_topology is used to keep the topology information.
+ * .cores_per_socket: tracks information on the count of cores
+ *                    per socket.
+ */
+S390Topology s390_topology = {
+    /* will be initialized after the CPU model is realized */
+    .cores_per_socket = NULL,
+};
+
+/**
+ * s390_socket_nb:
+ * @cpu: s390x CPU
+ *
+ * Returns the socket number used inside the cores_per_socket array
+ * for a topology tree entry
+ */
+static int s390_socket_nb_from_ids(int drawer_id, int book_id, int socket_id)
+{
+    return (drawer_id * current_machine->smp.books + book_id) *
+           current_machine->smp.sockets + socket_id;
+}
+
+/**
+ * s390_socket_nb:
+ * @cpu: s390x CPU
+ *
+ * Returns the socket number used inside the cores_per_socket array
+ * for a cpu.
+ */
+static int s390_socket_nb(S390CPU *cpu)
+{
+    return s390_socket_nb_from_ids(cpu->env.drawer_id, cpu->env.book_id,
+                                   cpu->env.socket_id);
+}
+
+/**
+ * s390_has_topology:
+ *
+ * Return: true if the topology is supported by the machine.
+ */
+bool s390_has_topology(void)
+{
+    return false;
+}
+
+/**
+ * s390_topology_init:
+ * @ms: the machine state where the machine topology is defined
+ *
+ * Keep track of the machine topology.
+ *
+ * Allocate an array to keep the count of cores per socket.
+ * The index of the array starts at socket 0 from book 0 and
+ * drawer 0 up to the maximum allowed by the machine topology.
+ */
+static void s390_topology_init(MachineState *ms)
+{
+    CpuTopology *smp = &ms->smp;
+
+    s390_topology.cores_per_socket = g_new0(uint8_t, smp->sockets *
+                                            smp->books * smp->drawers);
+}
+
+/**
+ * s390_topology_cpu_default:
+ * @cpu: pointer to a S390CPU
+ * @errp: Error pointer
+ *
+ * Setup the default topology if no attributes are already set.
+ * Passing a CPU with some, but not all, attributes set is considered
+ * an error.
+ *
+ * The function calculates the (drawer_id, book_id, socket_id)
+ * topology by filling the cores starting from the first socket
+ * (0, 0, 0) up to the last (smp->drawers, smp->books, smp->sockets).
+ *
+ * CPU type and dedication have defaults values set in the
+ * s390x_cpu_properties, entitlement must be adjust depending on the
+ * dedication.
+ *
+ * Returns false if it is impossible to setup a default topology
+ * true otherwise.
+ */
+static bool s390_topology_cpu_default(S390CPU *cpu, Error **errp)
+{
+    CpuTopology *smp = &current_machine->smp;
+    CPUS390XState *env = &cpu->env;
+
+    /* All geometry topology attributes must be set or all unset */
+    if ((env->socket_id < 0 || env->book_id < 0 || env->drawer_id < 0) &&
+        (env->socket_id >= 0 || env->book_id >= 0 || env->drawer_id >= 0)) {
+        error_setg(errp,
+                   "Please define all or none of the topology geometry attributes");
+        return false;
+    }
+
+    /* If one value is unset all are unset -> calculate defaults */
+    if (env->socket_id < 0) {
+        env->socket_id = s390_std_socket(env->core_id, smp);
+        env->book_id = s390_std_book(env->core_id, smp);
+        env->drawer_id = s390_std_drawer(env->core_id, smp);
+    }
+
+    /*
+     * When the user specifies the entitlement as 'auto' on the command line,
+     * QEMU will set the entitlement as:
+     * Medium when the CPU is not dedicated.
+     * High when dedicated is true.
+     */
+    if (env->entitlement == S390_CPU_ENTITLEMENT_AUTO) {
+        if (env->dedicated) {
+            env->entitlement = S390_CPU_ENTITLEMENT_HIGH;
+        } else {
+            env->entitlement = S390_CPU_ENTITLEMENT_MEDIUM;
+        }
+    }
+    return true;
+}
+
+/**
+ * s390_topology_check:
+ * @socket_id: socket to check
+ * @book_id: book to check
+ * @drawer_id: drawer to check
+ * @entitlement: entitlement to check
+ * @dedicated: dedication to check
+ * @errp: Error pointer
+ *
+ * The function checks if the topology
+ * attributes fits inside the system topology.
+ *
+ * Returns false if the specified topology does not match with
+ * the machine topology.
+ */
+static bool s390_topology_check(uint16_t socket_id, uint16_t book_id,
+                                uint16_t drawer_id, uint16_t entitlement,
+                                bool dedicated, Error **errp)
+{
+    CpuTopology *smp = &current_machine->smp;
+
+    if (socket_id >= smp->sockets) {
+        error_setg(errp, "Unavailable socket: %d", socket_id);
+        return false;
+    }
+    if (book_id >= smp->books) {
+        error_setg(errp, "Unavailable book: %d", book_id);
+        return false;
+    }
+    if (drawer_id >= smp->drawers) {
+        error_setg(errp, "Unavailable drawer: %d", drawer_id);
+        return false;
+    }
+    if (entitlement >= S390_CPU_ENTITLEMENT__MAX) {
+        error_setg(errp, "Unknown entitlement: %d", entitlement);
+        return false;
+    }
+    if (dedicated && (entitlement == S390_CPU_ENTITLEMENT_LOW ||
+                      entitlement == S390_CPU_ENTITLEMENT_MEDIUM)) {
+        error_setg(errp, "A dedicated CPU implies high entitlement");
+        return false;
+    }
+    return true;
+}
+
+/**
+ * s390_update_cpu_props:
+ * @ms: the machine state
+ * @cpu: the CPU for which to update the properties from the environment.
+ *
+ */
+static void s390_update_cpu_props(MachineState *ms, S390CPU *cpu)
+{
+    CpuInstanceProperties *props;
+
+    props = &ms->possible_cpus->cpus[cpu->env.core_id].props;
+
+    props->socket_id = cpu->env.socket_id;
+    props->book_id = cpu->env.book_id;
+    props->drawer_id = cpu->env.drawer_id;
+}
+
+/**
+ * s390_topology_setup_cpu:
+ * @ms: MachineState used to initialize the topology structure on
+ *      first call.
+ * @cpu: the new S390CPU to insert in the topology structure
+ * @errp: the error pointer
+ *
+ * Called from CPU hotplug to check and setup the CPU attributes
+ * before the CPU is inserted in the topology.
+ * There is no need to update the MTCR explicitly here because it
+ * will be updated by KVM on creation of the new CPU.
+ */
+void s390_topology_setup_cpu(MachineState *ms, S390CPU *cpu, Error **errp)
+{
+    int entry;
+
+    /*
+     * We do not want to initialize the topology if the CPU model
+     * does not support topology, consequently, we have to wait for
+     * the first CPU to be realized, which realizes the CPU model
+     * to initialize the topology structures.
+     *
+     * s390_topology_setup_cpu() is called from the CPU hotplug.
+     */
+    if (!s390_topology.cores_per_socket) {
+        s390_topology_init(ms);
+    }
+
+    if (!s390_topology_cpu_default(cpu, errp)) {
+        return;
+    }
+
+    if (!s390_topology_check(cpu->env.socket_id, cpu->env.book_id,
+                             cpu->env.drawer_id, cpu->env.entitlement,
+                             cpu->env.dedicated, errp)) {
+        return;
+    }
+
+    /* Do we still have space in the socket */
+    entry = s390_socket_nb(cpu);
+    if (s390_topology.cores_per_socket[entry] >= ms->smp.cores) {
+        error_setg(errp, "No more space on this socket");
+        return;
+    }
+
+    /* Update the count of cores in sockets */
+    s390_topology.cores_per_socket[entry] += 1;
+
+    /* topology tree is reflected in props */
+    s390_update_cpu_props(ms, cpu);
+}
diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build
index 6fd096813a..482fd13420 100644
--- a/hw/s390x/meson.build
+++ b/hw/s390x/meson.build
@@ -23,6 +23,7 @@ s390x_ss.add(when: 'CONFIG_KVM', if_true: files(
   's390-skeys-kvm.c',
   's390-stattrib-kvm.c',
   's390-pci-kvm.c',
+  'cpu-topology.c',
 ))
 s390x_ss.add(when: 'CONFIG_TCG', if_true: files(
   'tod-tcg.c',
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index c1123a9b45..7fe2bce20c 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -45,6 +45,7 @@
 #include "target/s390x/kvm/pv.h"
 #include "migration/blocker.h"
 #include "qapi/visitor.h"
+#include "hw/s390x/cpu-topology.h"
 
 static Error *pv_mig_blocker;
 
@@ -309,10 +310,18 @@ static void s390_cpu_plug(HotplugHandler *hotplug_dev,
 {
     MachineState *ms = MACHINE(hotplug_dev);
     S390CPU *cpu = S390_CPU(dev);
+    ERRP_GUARD();
 
     g_assert(!ms->possible_cpus->cpus[cpu->env.core_id].cpu);
     ms->possible_cpus->cpus[cpu->env.core_id].cpu = OBJECT(dev);
 
+    if (s390_has_topology()) {
+        s390_topology_setup_cpu(ms, cpu, errp);
+        if (*errp) {
+            return;
+        }
+    }
+
     if (dev->hotplugged) {
         raise_irq_cpu_hotplug();
     }
@@ -562,11 +571,20 @@ static const CPUArchIdList *s390_possible_cpu_arch_ids(MachineState *ms)
                                   sizeof(CPUArchId) * max_cpus);
     ms->possible_cpus->len = max_cpus;
     for (i = 0; i < ms->possible_cpus->len; i++) {
+        CpuInstanceProperties *props = &ms->possible_cpus->cpus[i].props;
+
         ms->possible_cpus->cpus[i].type = ms->cpu_type;
         ms->possible_cpus->cpus[i].vcpus_count = 1;
         ms->possible_cpus->cpus[i].arch_id = i;
-        ms->possible_cpus->cpus[i].props.has_core_id = true;
-        ms->possible_cpus->cpus[i].props.core_id = i;
+
+        props->has_core_id = true;
+        props->core_id = i;
+        props->has_socket_id = true;
+        props->socket_id = s390_std_socket(i, &ms->smp);
+        props->has_book_id = true;
+        props->book_id = s390_std_book(i, &ms->smp);
+        props->has_drawer_id = true;
+        props->drawer_id = s390_std_drawer(i, &ms->smp);
     }
 
     return ms->possible_cpus;
diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
new file mode 100644
index 0000000000..afef70a66d
--- /dev/null
+++ b/include/hw/s390x/cpu-topology.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022, 2023
+ * Author(s): Pierre Morel <pmorel@linux.ibm.com>
+ *
+ */
+#ifndef HW_S390X_CPU_TOPOLOGY_H
+#define HW_S390X_CPU_TOPOLOGY_H
+
+#ifndef CONFIG_USER_ONLY
+
+#include "qemu/queue.h"
+#include "hw/boards.h"
+#include "qapi/qapi-types-machine-target.h"
+
+typedef struct S390Topology {
+    uint8_t *cores_per_socket;
+} S390Topology;
+
+#ifdef CONFIG_KVM
+bool s390_has_topology(void);
+void s390_topology_setup_cpu(MachineState *ms, S390CPU *cpu, Error **errp);
+#else
+static inline bool s390_has_topology(void)
+{
+    return false;
+}
+static inline void s390_topology_setup_cpu(MachineState *ms,
+                                           S390CPU *cpu,
+                                           Error **errp) {}
+#endif
+
+extern S390Topology s390_topology;
+
+static inline int s390_std_socket(int n, CpuTopology *smp)
+{
+    return (n / smp->cores) % smp->sockets;
+}
+
+static inline int s390_std_book(int n, CpuTopology *smp)
+{
+    return (n / (smp->cores * smp->sockets)) % smp->books;
+}
+
+static inline int s390_std_drawer(int n, CpuTopology *smp)
+{
+    return (n / (smp->cores * smp->sockets * smp->books)) % smp->drawers;
+}
+
+#endif /* CONFIG_USER_ONLY */
+
+#endif