machine: pass QAPI struct to mc->smp_parse

As part of converting -smp to a property with a QAPI type, define
the struct and use it to do the actual parsing.  machine_smp_parse
takes care of doing the QemuOpts->QAPI conversion by hand, for now.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210617155308.928754-10-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/core/machine.c

@@ -739,12 +739,12 @@ void machine_set_cpu_numa_node(MachineState *machine,
     }
 }
 
-static void smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
+static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
 {
-    unsigned cpus    = qemu_opt_get_number(opts, "cpus", 0);
+    unsigned cpus    = config->has_cpus ? config->cpus : 0;
-    unsigned sockets = qemu_opt_get_number(opts, "sockets", 0);
+    unsigned sockets = config->has_sockets ? config->sockets : 0;
-    unsigned cores   = qemu_opt_get_number(opts, "cores", 0);
+    unsigned cores   = config->has_cores ? config->cores : 0;
-    unsigned threads = qemu_opt_get_number(opts, "threads", 0);
+    unsigned threads = config->has_threads ? config->threads : 0;
 
     /* compute missing values, prefer sockets over cores over threads */
     if (cpus == 0 || sockets == 0) {
@@ -754,8 +754,7 @@ static void smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
             sockets = sockets > 0 ? sockets : 1;
             cpus = cores * threads * sockets;
         } else {
-            ms->smp.max_cpus =
+            ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-                    qemu_opt_get_number(opts, "maxcpus", cpus);
             sockets = ms->smp.max_cpus / (cores * threads);
         }
     } else if (cores == 0) {
@@ -773,8 +772,7 @@ static void smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
         return;
     }
 
-    ms->smp.max_cpus =
+    ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-            qemu_opt_get_number(opts, "maxcpus", cpus);
 
     if (ms->smp.max_cpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");
@@ -1129,7 +1127,22 @@ bool machine_smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
     ERRP_GUARD();
 
     if (opts) {
-        mc->smp_parse(ms, opts, errp);
+        SMPConfiguration config = {
+            .has_cpus = !!qemu_opt_get(opts, "cpus"),
+            .cpus = qemu_opt_get_number(opts, "cpus", 0),
+            .has_sockets = !!qemu_opt_get(opts, "sockets"),
+            .sockets = qemu_opt_get_number(opts, "sockets", 0),
+            .has_dies = !!qemu_opt_get(opts, "dies"),
+            .dies = qemu_opt_get_number(opts, "dies", 0),
+            .has_cores = !!qemu_opt_get(opts, "cores"),
+            .cores = qemu_opt_get_number(opts, "cores", 0),
+            .has_threads = !!qemu_opt_get(opts, "threads"),
+            .threads = qemu_opt_get_number(opts, "threads", 0),
+            .has_maxcpus = !!qemu_opt_get(opts, "maxcpus"),
+            .maxcpus = qemu_opt_get_number(opts, "maxcpus", 0),
+        };
+
+        mc->smp_parse(ms, &config, errp);
         if (*errp) {
             return false;
         }

hw/i386/pc.c

@@ -710,13 +710,13 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, int level)
  * This function is very similar to smp_parse()
  * in hw/core/machine.c but includes CPU die support.
  */
-static void pc_smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
+static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
 {
-    unsigned cpus    = qemu_opt_get_number(opts, "cpus", 0);
+    unsigned cpus    = config->has_cpus ? config->cpus : 0;
-    unsigned sockets = qemu_opt_get_number(opts, "sockets", 0);
+    unsigned sockets = config->has_sockets ? config->sockets : 0;
-    unsigned dies = qemu_opt_get_number(opts, "dies", 1);
+    unsigned dies    = config->has_dies ? config->dies : 1;
-    unsigned cores   = qemu_opt_get_number(opts, "cores", 0);
+    unsigned cores   = config->has_cores ? config->cores : 0;
-    unsigned threads = qemu_opt_get_number(opts, "threads", 0);
+    unsigned threads = config->has_threads ? config->threads : 0;
 
     /* compute missing values, prefer sockets over cores over threads */
     if (cpus == 0 || sockets == 0) {
@@ -726,8 +726,7 @@ static void pc_smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
             sockets = sockets > 0 ? sockets : 1;
             cpus = cores * threads * dies * sockets;
         } else {
-            ms->smp.max_cpus =
+            ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-                    qemu_opt_get_number(opts, "maxcpus", cpus);
             sockets = ms->smp.max_cpus / (cores * threads * dies);
         }
     } else if (cores == 0) {
@@ -745,8 +744,7 @@ static void pc_smp_parse(MachineState *ms, QemuOpts *opts, Error **errp)
         return;
     }
 
-    ms->smp.max_cpus =
+    ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-            qemu_opt_get_number(opts, "maxcpus", cpus);
 
     if (ms->smp.max_cpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");

include/hw/boards.h

@@ -210,7 +210,7 @@ struct MachineClass {
     void (*reset)(MachineState *state);
     void (*wakeup)(MachineState *state);
     int (*kvm_type)(MachineState *machine, const char *arg);
-    void (*smp_parse)(MachineState *ms, QemuOpts *opts, Error **errp);
+    void (*smp_parse)(MachineState *ms, SMPConfiguration *config, Error **errp);
 
     BlockInterfaceType block_default_type;
     int units_per_default_bus;

qapi/machine.json

@@ -1284,3 +1284,31 @@
 ##
 { 'event': 'MEM_UNPLUG_ERROR',
   'data': { 'device': 'str', 'msg': 'str' } }
+
+##
+# @SMPConfiguration:
+#
+# Schema for CPU topology configuration.  "0" or a missing value lets
+# QEMU figure out a suitable value based on the ones that are provided.
+#
+# @cpus: number of virtual CPUs in the virtual machine
+#
+# @sockets: number of sockets in the CPU topology
+#
+# @dies: number of dies per socket in the CPU topology
+#
+# @cores: number of cores per thread in the CPU topology
+#
+# @threads: number of threads per core in the CPU topology
+#
+# @maxcpus: maximum number of hotpluggable virtual CPUs in the virtual machine
+#
+# Since: 6.1
+##
+{ 'struct': 'SMPConfiguration', 'data': {
+     '*cpus': 'int',
+     '*sockets': 'int',
+     '*dies': 'int',
+     '*cores': 'int',
+     '*threads': 'int',
+     '*maxcpus': 'int' } }