[Qemu-devel] [PATCH v3 1/2] machine: add default_ram_size to machine class

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Machines types can have different requirement for default ram
size. Introduce a member in the machine class and set the current
default_ram_size to 128MB.

For QEMUMachine types override the value during the registration of
the machine and for MachineClass introduce the generic class init
setting the default_ram_size.

In case the user passes memory that is lesser that the default ram
size, upscale the value to the machine's default ram size with a
warning.

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/core/machine.c   |  8 ++++++++
 include/hw/boards.h |  4 ++++
 vl.c                | 29 +++++++++++++++++------------
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index fbd91be..29c48de 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -403,11 +403,19 @@ bool machine_usb(MachineState *machine)
     return machine->usb;
 }
 
+static void machine_class_init(ObjectClass *oc, void *data)
+{
+    MachineClass *mc = MACHINE_CLASS(oc);
+
+    mc->default_ram_size = MACHINE_DEFAULT_RAM_SIZE;
+}
+
 static const TypeInfo machine_info = {
     .name = TYPE_MACHINE,
     .parent = TYPE_OBJECT,
     .abstract = true,
     .class_size = sizeof(MachineClass),
+    .class_init    = machine_class_init,
     .instance_size = sizeof(MachineState),
     .instance_init = machine_initfn,
     .instance_finalize = machine_finalize,
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 3ddc449..3fca4e0 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -62,6 +62,9 @@ int qemu_register_machine(QEMUMachine *m);
 #define MACHINE_CLASS(klass) \
     OBJECT_CLASS_CHECK(MachineClass, (klass), TYPE_MACHINE)
 
+/* Default 128 MB as guest ram size */
+#define MACHINE_DEFAULT_RAM_SIZE (1UL << 27)
+
 MachineClass *find_default_machine(void);
 extern MachineState *current_machine;
 
@@ -108,6 +111,7 @@ struct MachineClass {
     const char *default_display;
     GlobalProperty *compat_props;
     const char *hw_version;
+    ram_addr_t default_ram_size;
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
                                            DeviceState *dev);
diff --git a/vl.c b/vl.c
index 801d487..7af1c0b 100644
--- a/vl.c
+++ b/vl.c
@@ -120,8 +120,6 @@ int main(int argc, char **argv)
 #include "qom/object_interfaces.h"
 #include "qapi-event.h"
 
-#define DEFAULT_RAM_SIZE 128
-
 #define MAX_VIRTIO_CONSOLES 1
 #define MAX_SCLP_CONSOLES 1
 
@@ -1333,6 +1331,7 @@ static void machine_class_init(ObjectClass *oc, void *data)
     mc->is_default = qm->is_default;
     mc->default_machine_opts = qm->default_machine_opts;
     mc->default_boot_order = qm->default_boot_order;
+    mc->default_ram_size = MACHINE_DEFAULT_RAM_SIZE;
     mc->default_display = qm->default_display;
     mc->compat_props = qm->compat_props;
     mc->hw_version = qm->hw_version;
@@ -2641,13 +2640,13 @@ out:
     return 0;
 }
 
-static void set_memory_options(uint64_t *ram_slots, ram_addr_t *maxram_size)
+static void set_memory_options(uint64_t *ram_slots, ram_addr_t *maxram_size,
+                               MachineClass *mc)
 {
     uint64_t sz;
     const char *mem_str;
     const char *maxmem_str, *slots_str;
-    const ram_addr_t default_ram_size = (ram_addr_t)DEFAULT_RAM_SIZE *
-                                        1024 * 1024;
+    const ram_addr_t default_ram_size = mc->default_ram_size;
     QemuOpts *opts = qemu_find_opts_singleton("memory");
 
     sz = 0;
@@ -2684,6 +2683,12 @@ static void set_memory_options(uint64_t *ram_slots, ram_addr_t *maxram_size)
         exit(EXIT_FAILURE);
     }
 
+    if (ram_size < default_ram_size) {
+        fprintf(stderr, "WARNING: qemu: %s guest ram size defaulting to %ld MB\n",
+                mc->name, default_ram_size / (1024 * 1024));
+        ram_size = default_ram_size;
+    }
+
     /* store value for the future use */
     qemu_opt_set_number(opts, "size", ram_size, &error_abort);
     *maxram_size = ram_size;
@@ -3763,7 +3768,13 @@ int main(int argc, char **argv, char **envp)
         machine_class = machine_parse(optarg);
     }
 
-    set_memory_options(&ram_slots, &maxram_size);
+    if (machine_class == NULL) {
+        fprintf(stderr, "No machine specified, and there is no default.\n"
+                "Use -machine help to list supported machines!\n");
+        exit(1);
+    }
+
+    set_memory_options(&ram_slots, &maxram_size, machine_class);
 
     loc_set_none();
 
@@ -3792,12 +3803,6 @@ int main(int argc, char **argv, char **envp)
     }
 #endif
 
-    if (machine_class == NULL) {
-        fprintf(stderr, "No machine specified, and there is no default.\n"
-                "Use -machine help to list supported machines!\n");
-        exit(1);
-    }
-
     current_machine = MACHINE(object_new(object_class_get_name(
                           OBJECT_CLASS(machine_class))));
     if (machine_help_func(qemu_get_machine_opts(), current_machine)) {
-- 
1.8.3.1