[Qemu-devel] [PATCH v2 2/2] vl: convert -m to QemuOpts

[Igor Mammedov]

Adds option to -m
 "mem" - startup memory amount

For compatibility with legacy CLI if suffix-less number is passed,
it assumes amount in Mb.

Otherwise user is free to use suffixed number using suffixes b,k/K,M,G

Signed-off-by: Igor Mammedov <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
v2:
 - various fixes suggested by Laszlo Ersek <address@hidden>
   - check for overflow
   - check for empty mem="" case
   - reshuffle code to avoid conflicts with another series on list
   - some style/typo fixes
---
 qemu-options.hx |   12 ++++++---
 vl.c            |   68 ++++++++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 56e5fdf..42f7b64 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -210,14 +210,18 @@ use is discouraged as it may be removed from future 
versions.
 ETEXI
 
 DEF("m", HAS_ARG, QEMU_OPTION_m,
-    "-m megs         set virtual RAM size to megs MB [default="
-    stringify(DEFAULT_RAM_SIZE) "]\n", QEMU_ARCH_ALL)
+    "-m [mem=]size\n"
+    "                configure guest RAM size\n"
+    "                mem: initial amount of guest memory (default: "
+    stringify(DEFAULT_RAM_SIZE) "MB)\n",
+    QEMU_ARCH_ALL)
 STEXI
 @item -m @var{megs}
 @findex -m
-Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB.  Optionally,
+Set virtual RAM size to @var{size} megabytes. Default is 128 MiB.  Optionally,
 a suffix of ``M'' or ``G'' can be used to signify a value in megabytes or
-gigabytes respectively.
+gigabytes respectively. If @var{size} is provided without unit suffix then MB
+is assumed.
 ETEXI
 
 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
diff --git a/vl.c b/vl.c
index 7f2595c..410059d 100644
--- a/vl.c
+++ b/vl.c
@@ -302,6 +302,21 @@ static struct {
     { .driver = "qxl-vga",              .flag = &default_vga       },
 };
 
+#define MEMORY_OPTS "memory-opts"
+static QemuOptsList qemu_mem_opts = {
+    .name = MEMORY_OPTS,
+    .implied_opt_name = "mem",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_mem_opts.head),
+    .merge_lists = true,
+    .desc = {
+        {
+            .name = "mem",
+            .type = QEMU_OPT_SIZE,
+        },
+        { /* end of list */ }
+    },
+};
+
 static QemuOptsList qemu_rtc_opts = {
     .name = "rtc",
     .head = QTAILQ_HEAD_INITIALIZER(qemu_rtc_opts.head),
@@ -2868,6 +2883,8 @@ int main(int argc, char **argv, char **envp)
     };
     const char *trace_events = NULL;
     const char *trace_file = NULL;
+    const ram_addr_t default_ram_size = (ram_addr_t)DEFAULT_RAM_SIZE *
+                                        1024 * 1024;
 
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
@@ -2884,6 +2901,7 @@ int main(int argc, char **argv, char **envp)
 
     module_call_init(MODULE_INIT_QOM);
 
+    qemu_add_opts(&qemu_mem_opts);
     qemu_add_opts(&qemu_drive_opts);
     qemu_add_drive_opts(&qemu_legacy_drive_opts);
     qemu_add_drive_opts(&qemu_common_drive_opts);
@@ -2921,7 +2939,7 @@ int main(int argc, char **argv, char **envp)
     module_call_init(MODULE_INIT_MACHINE);
     machine = find_default_machine();
     cpu_model = NULL;
-    ram_size = 0;
+    ram_size = default_ram_size;
     snapshot = 0;
     cyls = heads = secs = 0;
     translation = BIOS_ATA_TRANSLATION_AUTO;
@@ -3198,16 +3216,45 @@ int main(int argc, char **argv, char **envp)
                 exit(0);
                 break;
             case QEMU_OPTION_m: {
-                int64_t value;
                 uint64_t sz;
-                char *end;
+                const char *mem_str;
+
+                opts = qemu_opts_parse(qemu_find_opts(MEMORY_OPTS),
+                                       optarg, 1);
+                if (!opts) {
+                    exit(1);
+                }
 
-                value = strtosz(optarg, &end);
-                if (value < 0 || *end) {
-                    fprintf(stderr, "qemu: invalid ram size: %s\n", optarg);
+                mem_str = qemu_opt_get(opts, "mem");
+                if (!mem_str) {
+                    fprintf(stderr, "qemu: invalid -m option, missing "
+                            "'mem' option\n");
+                    exit(1);
+                }
+                if (!strlen(mem_str)) {
+                    fprintf(stderr, "qemu: missing 'mem' option value\n");
                     exit(1);
                 }
-                sz = QEMU_ALIGN_UP((uint64_t)value, 8192);
+
+                sz = qemu_opt_get_size(opts, "mem", ram_size);
+
+                /* Fix up legacy suffix-less format */
+                if (g_ascii_isdigit(mem_str[strlen(mem_str) - 1])) {
+                    uint64_t overflow_check = sz;
+
+                    sz <<= 20;
+                    if ((sz >> 20) != overflow_check) {
+                        fprintf(stderr, "qemu: too large 'mem' option "
+                                "value\n");
+                    }
+                }
+
+                /* backward compatibility behaviour for case "-m 0" */
+                if (sz == 0) {
+                    sz = default_ram_size;
+                }
+
+                sz = QEMU_ALIGN_UP(sz, 8192);
                 ram_size = sz;
                 if (ram_size != sz) {
                     fprintf(stderr, "qemu: ram size too large\n");
@@ -4056,10 +4103,9 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
-    /* init the memory */
-    if (ram_size == 0) {
-        ram_size = DEFAULT_RAM_SIZE * 1024 * 1024;
-    }
+    /* store value for the future use */
+    qemu_opt_set_number(qemu_find_opts_singleton(MEMORY_OPTS),
+                        "mem", ram_size);
 
     if (qemu_opts_foreach(qemu_find_opts("device"), device_help_func, NULL, 0)
         != 0) {
-- 
1.7.1