Re: [PATCH v16 02/11] s390x/cpu topology: add topology entries on CPU hotplug

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On 22/02/2023 15.20, Pierre Morel wrote:
The topology information are attributes of the CPU and are
specified during the CPU device creation.
...
diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
index 83f31604cc..fa7f885a9f 100644
--- a/include/hw/s390x/cpu-topology.h
+++ b/include/hw/s390x/cpu-topology.h
@@ -10,6 +10,47 @@
  #ifndef HW_S390X_CPU_TOPOLOGY_H
  #define HW_S390X_CPU_TOPOLOGY_H
+#include "qemu/queue.h"
+#include "hw/boards.h"
+#include "qapi/qapi-types-machine-target.h"
+
  #define S390_TOPOLOGY_CPU_IFL   0x03
+typedef struct S390Topology {
+    uint8_t *cores_per_socket;
+    CpuTopology *smp;
+    CpuS390Polarization polarization;
+} 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;
+int s390_socket_nb(S390CPU *cpu);
+
+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->books;

Shouldn't that be " % smp->drawers" instead?

+}
+
  #endif
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
new file mode 100644
index 0000000000..59f2cc15c7
--- /dev/null
+++ b/hw/s390x/cpu-topology.c
@@ -0,0 +1,270 @@
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ * Author(s): Pierre Morel <pmorel@xxxxxxxxxxxxx>
+
+ * 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 "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "hw/boards.h"
+#include "qemu/typedefs.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.
+ * .smp: keeps track of the machine topology.
+ *
+ */
+S390Topology s390_topology = {
+    /* will be initialized after the cpu model is realized */
+    .cores_per_socket = NULL,
+    .smp = NULL,
+    .polarization = S390_CPU_POLARIZATION_HORIZONTAL,
+};
+
+/**
+ * s390_socket_nb:
+ * @cpu: s390x CPU
+ *
+ * Returns the socket number used inside the cores_per_socket array
+ * for a cpu.
+ */
+int s390_socket_nb(S390CPU *cpu)
+{
+    return (cpu->env.drawer_id * s390_topology.smp->books + cpu->env.book_id) *
+           s390_topology.smp->sockets + cpu->env.socket_id;
+}
+
+/**
+ * s390_has_topology:
+ *
+ * Return value: 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.smp = 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, entitlement and dedication have defaults values set in the
+ * s390x_cpu_properties, however entitlement is forced to 0 'none' when
+ * the polarization is horizontale.
+ */
+static void s390_topology_cpu_default(S390CPU *cpu, Error **errp)
+{
+    CpuTopology *smp = s390_topology.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;
+    }
+
+    /* Check if one of the geometry topology is unset */
+    if (env->socket_id < 0) {
+        /* Calculate default geometry topology attributes */
+        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);
+    }
+
+    if (s390_topology.polarization == S390_CPU_POLARIZATION_HORIZONTAL) {
+        env->entitlement = 0;

Should this be S390_CPU_ENTITLEMENT_HORIZONTAL instead of 0 ?

+    }
+}

 Thomas





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