vl.c: fix regression when reading memory size from config file

This is happening because an actual logic is performed on the memory
arguments inside the main's switch, disregarding the config file content.

Solved by extracting the logic on a separate function and calling it
after the switch.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/vl.c b/vl.c
index f6b24c4..6adb36e 100644
--- a/vl.c
+++ b/vl.c
@@ -2648,6 +2648,92 @@
     return 0;
 }
 
+static void set_memory_options(uint64_t *ram_slots, ram_addr_t *maxram_size)
+{
+    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;
+    QemuOpts *opts = qemu_find_opts_singleton("memory");
+
+    sz = 0;
+    mem_str = qemu_opt_get(opts, "size");
+    if (mem_str) {
+        if (!*mem_str) {
+            error_report("missing 'size' option value");
+            exit(EXIT_FAILURE);
+        }
+
+        sz = qemu_opt_get_size(opts, "size", 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) {
+                error_report("too large 'size' option value");
+                exit(EXIT_FAILURE);
+            }
+        }
+    }
+
+    /* 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) {
+        error_report("ram size too large");
+        exit(EXIT_FAILURE);
+    }
+
+    /* store value for the future use */
+    qemu_opt_set_number(opts, "size", ram_size);
+    *maxram_size = ram_size;
+
+    maxmem_str = qemu_opt_get(opts, "maxmem");
+    slots_str = qemu_opt_get(opts, "slots");
+    if (maxmem_str && slots_str) {
+        uint64_t slots;
+
+        sz = qemu_opt_get_size(opts, "maxmem", 0);
+        if (sz < ram_size) {
+            error_report("invalid -m option value: maxmem "
+                    "(0x%" PRIx64 ") <= initial memory (0x"
+                    RAM_ADDR_FMT ")", sz, ram_size);
+            exit(EXIT_FAILURE);
+        }
+
+        slots = qemu_opt_get_number(opts, "slots", 0);
+        if ((sz > ram_size) && !slots) {
+            error_report("invalid -m option value: maxmem "
+                    "(0x%" PRIx64 ") more than initial memory (0x"
+                    RAM_ADDR_FMT ") but no hotplug slots where "
+                    "specified", sz, ram_size);
+            exit(EXIT_FAILURE);
+        }
+
+        if ((sz <= ram_size) && slots) {
+            error_report("invalid -m option value:  %"
+                    PRIu64 " hotplug slots where specified but "
+                    "maxmem (0x%" PRIx64 ") <= initial memory (0x"
+                    RAM_ADDR_FMT ")", slots, sz, ram_size);
+            exit(EXIT_FAILURE);
+        }
+        *maxram_size = sz;
+        *ram_slots = slots;
+    } else if ((!maxmem_str && slots_str) ||
+            (maxmem_str && !slots_str)) {
+        error_report("invalid -m option value: missing "
+                "'%s' option", slots_str ? "maxmem" : "slots");
+        exit(EXIT_FAILURE);
+    }
+}
+
 int main(int argc, char **argv, char **envp)
 {
     int i;
@@ -2683,9 +2769,7 @@
     };
     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;
-    ram_addr_t maxram_size = default_ram_size;
+    ram_addr_t maxram_size;
     uint64_t ram_slots = 0;
     FILE *vmstate_dump_file = NULL;
     Error *main_loop_err = NULL;
@@ -2736,7 +2820,6 @@
     module_call_init(MODULE_INIT_MACHINE);
     machine_class = find_default_machine();
     cpu_model = NULL;
-    ram_size = default_ram_size;
     snapshot = 0;
     cyls = heads = secs = 0;
     translation = BIOS_ATA_TRANSLATION_AUTO;
@@ -3023,92 +3106,13 @@
                 version();
                 exit(0);
                 break;
-            case QEMU_OPTION_m: {
-                uint64_t sz;
-                const char *mem_str;
-                const char *maxmem_str, *slots_str;
-
+            case QEMU_OPTION_m:
                 opts = qemu_opts_parse(qemu_find_opts("memory"),
                                        optarg, 1);
                 if (!opts) {
                     exit(EXIT_FAILURE);
                 }
-
-                mem_str = qemu_opt_get(opts, "size");
-                if (!mem_str) {
-                    error_report("invalid -m option, missing 'size' option");
-                    exit(EXIT_FAILURE);
-                }
-                if (!*mem_str) {
-                    error_report("missing 'size' option value");
-                    exit(EXIT_FAILURE);
-                }
-
-                sz = qemu_opt_get_size(opts, "size", 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) {
-                        error_report("too large 'size' option value");
-                        exit(EXIT_FAILURE);
-                    }
-                }
-
-                /* 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) {
-                    error_report("ram size too large");
-                    exit(EXIT_FAILURE);
-                }
-                maxram_size = ram_size;
-
-                maxmem_str = qemu_opt_get(opts, "maxmem");
-                slots_str = qemu_opt_get(opts, "slots");
-                if (maxmem_str && slots_str) {
-                    uint64_t slots;
-
-                    sz = qemu_opt_get_size(opts, "maxmem", 0);
-                    if (sz < ram_size) {
-                        error_report("invalid -m option value: maxmem "
-                                "(0x%" PRIx64 ") <= initial memory (0x"
-                                RAM_ADDR_FMT ")", sz, ram_size);
-                        exit(EXIT_FAILURE);
-                    }
-
-                    slots = qemu_opt_get_number(opts, "slots", 0);
-                    if ((sz > ram_size) && !slots) {
-                        error_report("invalid -m option value: maxmem "
-                                "(0x%" PRIx64 ") more than initial memory (0x"
-                                RAM_ADDR_FMT ") but no hotplug slots where "
-                                "specified", sz, ram_size);
-                        exit(EXIT_FAILURE);
-                    }
-
-                    if ((sz <= ram_size) && slots) {
-                        error_report("invalid -m option value:  %"
-                                PRIu64 " hotplug slots where specified but "
-                                "maxmem (0x%" PRIx64 ") <= initial memory (0x"
-                                RAM_ADDR_FMT ")", slots, sz, ram_size);
-                        exit(EXIT_FAILURE);
-                    }
-                    maxram_size = sz;
-                    ram_slots = slots;
-                } else if ((!maxmem_str && slots_str) ||
-                           (maxmem_str && !slots_str)) {
-                    error_report("invalid -m option value: missing "
-                            "'%s' option", slots_str ? "maxmem" : "slots");
-                    exit(EXIT_FAILURE);
-                }
                 break;
-            }
 #ifdef CONFIG_TPM
             case QEMU_OPTION_tpmdev:
                 if (tpm_config_parse(qemu_find_opts("tpmdev"), optarg) < 0) {
@@ -3757,6 +3761,8 @@
         machine_class = machine_parse(optarg);
     }
 
+    set_memory_options(&ram_slots, &maxram_size);
+
     loc_set_none();
 
     os_daemonize();
@@ -4006,9 +4012,6 @@
         exit(1);
     }
 
-    /* store value for the future use */
-    qemu_opt_set_number(qemu_find_opts_singleton("memory"), "size", ram_size);
-
     if (qemu_opts_foreach(qemu_find_opts("device"), device_help_func, NULL, 0)
         != 0) {
         exit(0);