[Qemu-devel] [PATCH v2 2/2] basic machine opts framework

[Glauber Costa]

This patch adds initial support for the -machine option, that allows
command line specification of machine attributes (always relying on safe
defaults). Besides its value per-se, it is the saner way we found to
allow for enabling/disabling of kvm's in-kernel irqchip.

A machine with in-kernel-irqchip could be specified as:
        -machine irqchip=apic-kvm
And one without it:
        -machine irqchip=apic

To demonstrate how it'd work, this patch introduces a choice between
"pic" and "apic", pic being the old-style isa thing.
---
 hw/boards.h     |   10 ++++++++++
 hw/pc.c         |   45 +++++++++++++++++++++++++++++++++++++++------
 qemu-config.c   |   16 ++++++++++++++++
 qemu-config.h   |    1 +
 qemu-options.hx |    9 +++++++++
 vl.c            |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 129 insertions(+), 6 deletions(-)

diff --git a/hw/boards.h b/hw/boards.h
index d889341..187794e 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -12,6 +12,15 @@ typedef void QEMUMachineInitFunc(ram_addr_t ram_size,
                                  const char *initrd_filename,
                                  const char *cpu_model);
 
+typedef void (QEMUIrqchipFunc)(void *opaque);
+
+typedef struct QEMUIrqchip {
+    const char *name;
+    QEMUIrqchipFunc *init; 
+    int used;
+    int is_default;
+} QEMUIrqchip;
+
 typedef struct QEMUMachine {
     const char *name;
     const char *alias;
@@ -21,6 +30,7 @@ typedef struct QEMUMachine {
     int max_cpus;
     int is_default;
     CompatProperty *compat_props;
+    QEMUIrqchip *irqchip;
     struct QEMUMachine *next;
 } QEMUMachine;
 
diff --git a/hw/pc.c b/hw/pc.c
index 408d6d6..b3de30a 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1007,21 +1007,43 @@ int cpu_is_bsp(CPUState *env)
     return env->cpuid_apic_id == 0;
 }
 
+static void qemu_apic_init(void *opaque)
+{
+    CPUState *env = opaque;
+    if (!(env->cpuid_features & CPUID_APIC)) {
+        fprintf(stderr, "CPU lacks APIC cpuid flag\n");
+        exit(1);
+    }
+    env->cpuid_apic_id = env->cpu_index;
+    /* APIC reset callback resets cpu */
+    apic_init(env);
+}
+
+static void qemu_pic_init(void *opaque)
+{
+    CPUState *env = opaque;
+
+    if (smp_cpus > 1) {
+        fprintf(stderr, "PIC can't support smp systems\n");
+        exit(1);
+    }
+    qemu_register_reset((QEMUResetHandler*)cpu_reset, env);
+}
+
 static CPUState *pc_new_cpu(const char *cpu_model)
 {
     CPUState *env;
+    QEMUIrqchip *ic;
 
     env = cpu_init(cpu_model);
     if (!env) {
         fprintf(stderr, "Unable to find x86 CPU definition\n");
         exit(1);
     }
-    if ((env->cpuid_features & CPUID_APIC) || smp_cpus > 1) {
-        env->cpuid_apic_id = env->cpu_index;
-        /* APIC reset callback resets cpu */
-        apic_init(env);
-    } else {
-        qemu_register_reset((QEMUResetHandler*)cpu_reset, env);
+
+    for (ic = current_machine->irqchip; ic->name != NULL; ic++) {
+        if (ic->used)
+            ic->init(env);
     }
     return env;
 }
@@ -1370,6 +1392,17 @@ static QEMUMachine pc_machine = {
     .desc = "Standard PC",
     .init = pc_init_pci,
     .max_cpus = 255,
+    .irqchip = (QEMUIrqchip[]){
+        {
+            .name = "apic",
+            .init = qemu_apic_init,
+            .is_default = 1,
+        },{
+            .name = "pic",
+            .init = qemu_pic_init,
+        },
+        { /* end of list */ },
+    },
     .is_default = 1,
 };
 
diff --git a/qemu-config.c b/qemu-config.c
index cae92f7..e83b301 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -196,6 +196,21 @@ QemuOptsList qemu_rtc_opts = {
     },
 };
 
+QemuOptsList qemu_machine_opts = {
+    .name = "M",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_machine_opts.head),
+    .desc = {
+        {
+            .name = "mach",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "irqchip",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
 static QemuOptsList *lists[] = {
     &qemu_drive_opts,
     &qemu_chardev_opts,
@@ -203,6 +218,7 @@ static QemuOptsList *lists[] = {
     &qemu_netdev_opts,
     &qemu_net_opts,
     &qemu_rtc_opts,
+    &qemu_machine_opts,
     NULL,
 };
 
diff --git a/qemu-config.h b/qemu-config.h
index 3cc8864..9b02ee0 100644
--- a/qemu-config.h
+++ b/qemu-config.h
@@ -7,6 +7,7 @@ extern QemuOptsList qemu_device_opts;
 extern QemuOptsList qemu_netdev_opts;
 extern QemuOptsList qemu_net_opts;
 extern QemuOptsList qemu_rtc_opts;
+extern QemuOptsList qemu_machine_opts;
 
 int qemu_set_option(const char *str);
 
diff --git a/qemu-options.hx b/qemu-options.hx
index 20aa242..4dfc55a 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -31,6 +31,15 @@ STEXI
 Select the emulated @var{machine} (@code{-M ?} for list)
 ETEXI
 
+DEF("machine", HAS_ARG, QEMU_OPTION_machine,
+    "-machine mach=m[,irqchip=chip]\n"
+    "    select emulated machine (-machine ? for list)\n")
+STEXI
address@hidden -machine @var{machine}[,@var{option}]
address@hidden -machine
+Select the emulated @var{machine} (@code{-machine ?} for list)
+ETEXI
+
 DEF("cpu", HAS_ARG, QEMU_OPTION_cpu,
     "-cpu cpu        select CPU (-cpu ? for list)\n")
 STEXI
diff --git a/vl.c b/vl.c
index 7a8b20b..cabbd1e 100644
--- a/vl.c
+++ b/vl.c
@@ -3217,9 +3217,15 @@ static QEMUMachine *find_machine(const char *name)
 static QEMUMachine *find_default_machine(void)
 {
     QEMUMachine *m;
+    QEMUIrqchip *ic;
 
     for(m = first_machine; m != NULL; m = m->next) {
         if (m->is_default) {
+            for (ic = m->irqchip; ic->name != NULL; ic++) {
+                if (ic->is_default) {
+                    ic->used = 1;
+                }
+            }
             return m;
         }
     }
@@ -4902,6 +4908,54 @@ int main(int argc, char **argv, char **envp)
                     exit(*optarg != '?');
                 }
                 break;
+            case QEMU_OPTION_machine: {
+                const char *mach;
+                const char *op;
+
+                opts = qemu_opts_parse(&qemu_machine_opts, optarg, 0);
+                if (!opts) {
+                    fprintf(stderr, "parse error: %s\n", optarg);
+                    exit(1);
+                }
+                
+                mach = qemu_opt_get(opts, "mach");
+
+                if (mach) {
+                    machine = find_machine(mach);
+                    if (!machine) {
+                        QEMUMachine *m;
+                        printf("Supported machines are:\n");
+                        for(m = first_machine; m != NULL; m = m->next) {
+                            if (m->alias)
+                                printf("%-10s %s (alias of %s)\n",
+                                       m->alias, m->desc, m->name);
+                            printf("%-10s %s%s\n",
+                                   m->name, m->desc,
+                                   m->is_default ? " (default)" : "");
+                        }
+                        exit(*optarg != '?');
+                    }
+                }
+
+                op = qemu_opt_get(opts, "irqchip");
+                if (op) {
+                    int found = 0;
+                    QEMUIrqchip *ic;
+                    for (ic = machine->irqchip; ic->name != NULL; ic++) {
+                       if (!strcmp(op, ic->name)) {
+                        ic->used = 1;
+                        found = 1;
+                       } else
+                        ic->used = 0;
+                    }
+                    if (!found) {
+                        fprintf(stderr, "irqchip %s not found\n", op);
+                        exit(1);
+                        
+                    }
+                }
+                break;
+            }
             case QEMU_OPTION_cpu:
                 /* hw initialization will check this */
                 if (*optarg == '?') {
-- 
1.6.2.2