[Qemu-devel] [PATCH v2 2/5] vl.c: extend -m option to support options for memory hotplug

[Matthew Rosato <mjrosato@linux.vnet.ibm.com>]

From: Igor Mammedov <imammedo@redhat.com>

Add following parameters:
  "slots" - total number of hotplug memory slots
  "maxmem" - maximum possible memory

"slots" and "maxmem" should go in pair and "maxmem" should be greater
than "mem" for memory hotplug to be enabled.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 qemu-options.hx |    7 +++++--
 vl.c            |   45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 4d7ef52..ff60504 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -210,10 +210,13 @@ use is discouraged as it may be removed from future versions.
 ETEXI
 
 DEF("m", HAS_ARG, QEMU_OPTION_m,
-    "-m [mem=]megs\n"
+    "-m [mem=]megs[,slots=n,maxmem=size]\n"
     "                configure guest RAM\n"
     "                mem: initial amount of guest memory (default: "
-    stringify(DEFAULT_RAM_SIZE) "Mb)\n",
+    stringify(DEFAULT_RAM_SIZE) "Mb)\n"
+    "                slots=number of hotplug slots (default: none)\n"
+    "                maxmem=maximum amount of guest memory (default: none)\n"
+    "                slots and maxmem must be used together\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -m @var{megs}
diff --git a/vl.c b/vl.c
index a3e43d6..d8ff51f 100644
--- a/vl.c
+++ b/vl.c
@@ -542,6 +542,14 @@ static QemuOptsList qemu_mem_opts = {
             .name = "mem",
             .type = QEMU_OPT_SIZE,
         },
+        {
+            .name = "slots",
+            .type = QEMU_OPT_NUMBER,
+        },
+        {
+            .name = "maxmem",
+            .type = QEMU_OPT_SIZE,
+        },
         { /* end of list */ }
     },
 };
@@ -3226,6 +3234,7 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_m: {
                 uint64_t sz;
                 const char *mem_str;
+                const char *maxmem_str, *slots_str;
 
                 opts = qemu_opts_parse(qemu_find_opts("memory-opts"),
                                        optarg, 1);
@@ -3255,6 +3264,42 @@ int main(int argc, char **argv, char **envp)
                     fprintf(stderr, "qemu: ram size too large\n");
                     exit(1);
                 }
+
+                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) {
+                        fprintf(stderr, "qemu: invalid -m option value: maxmem "
+                                "(%" PRIu64 ") <= initial memory (%"
+                                PRIu64 ")\n", sz, ram_size);
+                        exit(1);
+                    }
+
+                    slots = qemu_opt_get_number(opts, "slots", 0);
+                    if ((sz > ram_size) && !slots) {
+                        fprintf(stderr, "qemu: invalid -m option value: maxmem "
+                                "(%" PRIu64 ") more than initial memory (%"
+                                PRIu64 ") but no hotplug slots where "
+                                "specified\n", sz, ram_size);
+                        exit(1);
+                    }
+
+                    if ((sz <= ram_size) && slots) {
+                        fprintf(stderr, "qemu: invalid -m option value:  %"
+                                PRIu64 " hotplug slots where specified but "
+                                "maxmem (%" PRIu64 ") <= initial memory (%"
+                                PRIu64 ")\n", slots, sz, ram_size);
+                        exit(1);
+                    }
+                } else if ((!maxmem_str && slots_str) ||
+                           (maxmem_str && !slots_str)) {
+                    fprintf(stderr, "qemu: invalid -m option value: missing "
+                            "'%s' option\n", slots_str ? "maxmem" : "slots");
+                    exit(1);
+                }
                 break;
             }
 #ifdef CONFIG_TPM
-- 
1.7.9.5