[Qemu-devel] [PATCH v1 3/4] hw: Deduce the default machine from the specified CPU model

[Meador Inge]

This changes the driver behavior to choose the default machine
model based on the CPU being used.  Defaulting the machine this
way makes it easier to use QEMU as an ISS by just specifying
the -cpu option since a default machine that is suitable for
emulating the full ISA can be chosen.

For example, currently on ARM the ARM Integrator/CP board is
chosen as the default machine when specifying just a CPU.
However, this doesn't work well when passing -cpu cortex-m3
since on ARMv7-M processors the NVIC is a part of the architecture
and is needed to support instructions like SVC.

Signed-off-by: Meador Inge <address@hidden>
---
 hw/alpha_dp264.c              |    2 +-
 hw/axis_dev88.c               |    2 +-
 hw/boards.h                   |    4 ++--
 hw/integratorcp.c             |    2 +-
 hw/lm32_boards.c              |    3 +--
 hw/mcf5208.c                  |    2 +-
 hw/milkymist.c                |    1 -
 hw/mips_malta.c               |    2 +-
 hw/openrisc_sim.c             |    2 +-
 hw/pc_piix.c                  |    2 +-
 hw/pc_sysfw.c                 |    2 +-
 hw/petalogix_ml605_mmu.c      |    1 -
 hw/petalogix_s3adsp1800_mmu.c |    2 +-
 hw/ppc_newworld.c             |    2 +-
 hw/ppc_oldworld.c             |    2 +-
 hw/puv3.c                     |    2 +-
 hw/s390-virtio.c              |    2 +-
 hw/shix.c                     |    2 +-
 hw/sun4m.c                    |    2 +-
 hw/sun4u.c                    |    2 +-
 hw/xtensa_sim.c               |    2 +-
 qapi-schema.json              |    4 ++--
 vl.c                          |   38 +++++++++++++++++++++++++-------------
 23 files changed, 47 insertions(+), 38 deletions(-)

diff --git a/hw/alpha_dp264.c b/hw/alpha_dp264.c
index 9eb939f..d6717aa 100644
--- a/hw/alpha_dp264.c
+++ b/hw/alpha_dp264.c
@@ -169,7 +169,7 @@ static QEMUMachine clipper_machine = {
     .desc = "Alpha DP264/CLIPPER",
     .init = clipper_init,
     .max_cpus = 4,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void clipper_machine_init(void)
diff --git a/hw/axis_dev88.c b/hw/axis_dev88.c
index eab6327..41078e6 100644
--- a/hw/axis_dev88.c
+++ b/hw/axis_dev88.c
@@ -353,7 +353,7 @@ static QEMUMachine axisdev88_machine = {
     .name = "axis-dev88",
     .desc = "AXIS devboard 88",
     .init = axisdev88_init,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void axisdev88_machine_init(void)
diff --git a/hw/boards.h b/hw/boards.h
index a2e0a54..6f52561 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -28,7 +28,7 @@ typedef struct QEMUMachine {
         no_floppy:1,
         no_cdrom:1,
         no_sdcard:1;
-    int is_default;
+    const char* default_for_cpu_model;
     const char *default_machine_opts;
     GlobalProperty *compat_props;
     struct QEMUMachine *next;
@@ -36,7 +36,7 @@ typedef struct QEMUMachine {
 } QEMUMachine;
 
 int qemu_register_machine(QEMUMachine *m);
-QEMUMachine *find_default_machine(void);
+QEMUMachine *find_default_machine(const char *cpu_model);
 
 extern QEMUMachine *current_machine;
 
diff --git a/hw/integratorcp.c b/hw/integratorcp.c
index d0e2e90..4df0774 100644
--- a/hw/integratorcp.c
+++ b/hw/integratorcp.c
@@ -509,7 +509,7 @@ static QEMUMachine integratorcp_machine = {
     .name = "integratorcp",
     .desc = "ARM Integrator/CP (ARM926EJ-S)",
     .init = integratorcp_init,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void integratorcp_machine_init(void)
diff --git a/hw/lm32_boards.c b/hw/lm32_boards.c
index b76d800..2e5348b 100644
--- a/hw/lm32_boards.c
+++ b/hw/lm32_boards.c
@@ -290,14 +290,13 @@ static QEMUMachine lm32_evr_machine = {
     .name = "lm32-evr",
     .desc = "LatticeMico32 EVR32 eval system",
     .init = lm32_evr_init,
-    .is_default = 1
+    .default_for_cpu_model = "any",
 };
 
 static QEMUMachine lm32_uclinux_machine = {
     .name = "lm32-uclinux",
     .desc = "lm32 platform for uClinux and u-boot by Theobroma Systems",
     .init = lm32_uclinux_init,
-    .is_default = 0
 };
 
 static void lm32_machine_init(void)
diff --git a/hw/mcf5208.c b/hw/mcf5208.c
index ee25b1b..0e28ffd9 100644
--- a/hw/mcf5208.c
+++ b/hw/mcf5208.c
@@ -291,7 +291,7 @@ static QEMUMachine mcf5208evb_machine = {
     .name = "mcf5208evb",
     .desc = "MCF5206EVB",
     .init = mcf5208evb_init,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void mcf5208evb_machine_init(void)
diff --git a/hw/milkymist.c b/hw/milkymist.c
index 2e7235b..a8606ea 100644
--- a/hw/milkymist.c
+++ b/hw/milkymist.c
@@ -207,7 +207,6 @@ static QEMUMachine milkymist_machine = {
     .name = "milkymist",
     .desc = "Milkymist One",
     .init = milkymist_init,
-    .is_default = 0
 };
 
 static void milkymist_machine_init(void)
diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index ad23f26..ac955e9 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -1020,7 +1020,7 @@ static QEMUMachine mips_malta_machine = {
     .desc = "MIPS Malta Core LV",
     .init = mips_malta_init,
     .max_cpus = 16,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void mips_malta_register_types(void)
diff --git a/hw/openrisc_sim.c b/hw/openrisc_sim.c
index 55e97f0..a037fc8 100644
--- a/hw/openrisc_sim.c
+++ b/hw/openrisc_sim.c
@@ -139,7 +139,7 @@ static QEMUMachine openrisc_sim_machine = {
     .desc = "or32 simulation",
     .init = openrisc_sim_init,
     .max_cpus = 1,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void openrisc_sim_machine_init(void)
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 88ff041..6226e8e 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -355,7 +355,7 @@ static QEMUMachine pc_machine_v1_2 = {
     .desc = "Standard PC",
     .init = pc_init_pci,
     .max_cpus = 255,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 #define PC_COMPAT_1_1 \
diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
index b45f0ac..9e034d2 100644
--- a/hw/pc_sysfw.c
+++ b/hw/pc_sysfw.c
@@ -93,7 +93,7 @@ static void pc_fw_add_pflash_drv(void)
       return;
     }
 
-    machine = find_default_machine();
+    machine = find_default_machine(NULL);
     if (machine == NULL) {
       return;
     }
diff --git a/hw/petalogix_ml605_mmu.c b/hw/petalogix_ml605_mmu.c
index dced648..48d20df 100644
--- a/hw/petalogix_ml605_mmu.c
+++ b/hw/petalogix_ml605_mmu.c
@@ -148,7 +148,6 @@ static QEMUMachine petalogix_ml605_machine = {
     .name = "petalogix-ml605",
     .desc = "PetaLogix linux refdesign for xilinx ml605 little endian",
     .init = petalogix_ml605_init,
-    .is_default = 0
 };
 
 static void petalogix_ml605_machine_init(void)
diff --git a/hw/petalogix_s3adsp1800_mmu.c b/hw/petalogix_s3adsp1800_mmu.c
index 2cf6882..48a17c7 100644
--- a/hw/petalogix_s3adsp1800_mmu.c
+++ b/hw/petalogix_s3adsp1800_mmu.c
@@ -117,7 +117,7 @@ static QEMUMachine petalogix_s3adsp1800_machine = {
     .name = "petalogix-s3adsp1800",
     .desc = "PetaLogix linux refdesign for xilinx Spartan 3ADSP1800",
     .init = petalogix_s3adsp1800_init,
-    .is_default = 1
+    .default_for_cpu_model = "any",
 };
 
 static void petalogix_s3adsp1800_machine_init(void)
diff --git a/hw/ppc_newworld.c b/hw/ppc_newworld.c
index e95cfe8..50f2ed3 100644
--- a/hw/ppc_newworld.c
+++ b/hw/ppc_newworld.c
@@ -424,7 +424,7 @@ static QEMUMachine core99_machine = {
     .init = ppc_core99_init,
     .max_cpus = MAX_CPUS,
 #ifdef TARGET_PPC64
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 #endif
 };
 
diff --git a/hw/ppc_oldworld.c b/hw/ppc_oldworld.c
index 1dcd8a6..868ab82 100644
--- a/hw/ppc_oldworld.c
+++ b/hw/ppc_oldworld.c
@@ -339,7 +339,7 @@ static QEMUMachine heathrow_machine = {
     .init = ppc_heathrow_init,
     .max_cpus = MAX_CPUS,
 #ifndef TARGET_PPC64
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 #endif
 };
 
diff --git a/hw/puv3.c b/hw/puv3.c
index 43f7216..b8ba049 100644
--- a/hw/puv3.c
+++ b/hw/puv3.c
@@ -119,7 +119,7 @@ static QEMUMachine puv3_machine = {
     .name = "puv3",
     .desc = "PKUnity Version-3 based on UniCore32",
     .init = puv3_init,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
     .use_scsi = 0,
 };
 
diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index 47eed35..9fcd608 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -341,7 +341,7 @@ static QEMUMachine s390_machine = {
     .no_sdcard = 1,
     .use_virtcon = 1,
     .max_cpus = 255,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void s390_machine_init(void)
diff --git a/hw/shix.c b/hw/shix.c
index dd9ce17..09bcce4 100644
--- a/hw/shix.c
+++ b/hw/shix.c
@@ -93,7 +93,7 @@ static QEMUMachine shix_machine = {
     .name = "shix",
     .desc = "shix card",
     .init = shix_init,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static void shix_machine_init(void)
diff --git a/hw/sun4m.c b/hw/sun4m.c
index 0f909b5..2c45f03 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -1386,7 +1386,7 @@ static QEMUMachine ss5_machine = {
     .desc = "Sun4m platform, SPARCstation 5",
     .init = ss5_init,
     .use_scsi = 1,
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static QEMUMachine ss10_machine = {
diff --git a/hw/sun4u.c b/hw/sun4u.c
index 07cd042..9858e79 100644
--- a/hw/sun4u.c
+++ b/hw/sun4u.c
@@ -964,7 +964,7 @@ static QEMUMachine sun4u_machine = {
     .desc = "Sun4u platform",
     .init = sun4u_init,
     .max_cpus = 1, // XXX for now
-    .is_default = 1,
+    .default_for_cpu_model = "any",
 };
 
 static QEMUMachine sun4v_machine = {
diff --git a/hw/xtensa_sim.c b/hw/xtensa_sim.c
index 831460b..78f5eea 100644
--- a/hw/xtensa_sim.c
+++ b/hw/xtensa_sim.c
@@ -111,7 +111,7 @@ static void xtensa_sim_init(ram_addr_t ram_size,
 static QEMUMachine xtensa_sim_machine = {
     .name = "sim",
     .desc = "sim machine (" XTENSA_DEFAULT_CPU_MODEL ")",
-    .is_default = true,
+    .default_for_cpu_model = "any",
     .init = xtensa_sim_init,
     .max_cpus = 4,
 };
diff --git a/qapi-schema.json b/qapi-schema.json
index bd8ad74..e210ec6 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2315,13 +2315,13 @@
 #
 # @alias: #optional an alias for the machine name
 #
-# @default: #optional whether the machine is default
+# @default-for-cpu-model: #optional the machine is default for the given cpu
 #
 # Since: 1.2.0
 ##
 { 'type': 'MachineInfo',
   'data': { 'name': 'str', '*alias': 'str',
-            '*is-default': 'bool' } }
+            '*default-for-cpu-model': 'str' } }
 
 ##
 # @query-machines:
diff --git a/vl.c b/vl.c
index 7c577fa..1f945a2 100644
--- a/vl.c
+++ b/vl.c
@@ -1226,16 +1226,25 @@ static QEMUMachine *find_machine(const char *name)
     return NULL;
 }
 
-QEMUMachine *find_default_machine(void)
+/* Find the default machine implementation for the given cpu_model.
+ * If cpu_model is NULL, then pick the one that matches "any".
+ */
+QEMUMachine *find_default_machine(const char *cpu_model)
 {
     QEMUMachine *m;
+    QEMUMachine *best_match = NULL;
+    QEMUMachine *any_match = NULL;
 
     for(m = first_machine; m != NULL; m = m->next) {
-        if (m->is_default) {
-            return m;
+        if (m->default_for_cpu_model) {
+            if (cpu_model && strcmp(m->default_for_cpu_model, cpu_model) == 0) 
{
+                best_match = m;
+            } else if (strcmp(m->default_for_cpu_model, "any") == 0) {
+                any_match = m;
+            }
         }
     }
-    return NULL;
+    return best_match ? best_match : any_match;
 }
 
 MachineInfoList *qmp_query_machines(Error **errp)
@@ -1248,9 +1257,9 @@ MachineInfoList *qmp_query_machines(Error **errp)
         MachineInfo *info;
 
         info = g_malloc0(sizeof(*info));
-        if (m->is_default) {
-            info->has_is_default = true;
-            info->is_default = true;
+        if (m->default_for_cpu_model) {
+            info->has_default_for_cpu_model = true;
+            info->default_for_cpu_model = g_strdup(m->default_for_cpu_model);
         }
 
         if (m->alias) {
@@ -2166,8 +2175,12 @@ static QEMUMachine *machine_parse(const char *name)
         if (m->alias) {
             printf("%-20s %s (alias of %s)\n", m->alias, m->desc, m->name);
         }
-        printf("%-20s %s%s\n", m->name, m->desc,
-               m->is_default ? " (default)" : "");
+        if (m->default_for_cpu_model) {
+            printf("%-20s %s (default for cpu \"%s\")\n", m->name, m->desc,
+                   m->default_for_cpu_model);
+        } else {
+            printf("%-20s %s\n", m->name, m->desc);
+        }
     }
     exit(!name || !is_help_option(name));
 }
@@ -2404,7 +2417,7 @@ int main(int argc, char **argv, char **envp)
     os_setup_early_signal_handling();
 
     module_call_init(MODULE_INIT_MACHINE);
-    machine = find_default_machine();
+    machine = NULL;
     cpu_model = NULL;
     ram_size = 0;
     snapshot = 0;
@@ -3299,9 +3312,8 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
-    if (machine == NULL) {
-        fprintf(stderr, "No machine found.\n");
-        exit(1);
+    if (!machine) {
+        machine = find_default_machine(cpu_model);
     }
 
     if (machine->hw_version) {
-- 
1.7.7.6