[Qemu-devel] [PATCH] mempath: add option to specify minimum huge page size

[Marcelo Tosatti <mtosatti@redhat.com>]

Failing initialization in case hugepage path has 
hugepage smaller than specified.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/exec.c b/exec.c
index b69fd29..c95a0f3 100644
--- a/exec.c
+++ b/exec.c
@@ -1034,6 +1034,13 @@ static void *file_ram_alloc(RAMBlock *block,
         return NULL;
     }
 
+    if (mem_path_min_hpagesize && hpagesize < mem_path_min_hpagesize) {
+        fprintf(stderr, "mount point (%s) has page size "
+                "(%ld) < (%ld) = min_hpagesize\n", path, hpagesize,
+                mem_path_min_hpagesize);
+        exit(1);
+    }
+
     if (memory < hpagesize) {
         return NULL;
     }
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 4cb4b4a..cc9e28a 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -470,6 +470,7 @@ extern RAMList ram_list;
 
 extern const char *mem_path;
 extern int mem_prealloc;
+extern unsigned long int mem_path_min_hpagesize;
 
 /* Flags stored in the low bits of the TLB virtual address.  These are
    defined so that fast path ram access is all zeros.  */
diff --git a/qemu-options.hx b/qemu-options.hx
index 56e5fdf..36743e1 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -221,9 +221,9 @@ gigabytes respectively.
 ETEXI
 
 DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
-    "-mem-path FILE  provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
+    "-mem-path [mem-path=]file[,min-hpage-size=value]  provide backing storage for guest RAM\n", QEMU_ARCH_ALL)
 STEXI
-@item -mem-path @var{path}
+@item -mem-path [mem-path=]@var{path}[,min-hpage-size=@var{min-hpage-size}]
 @findex -mem-path
 Allocate guest RAM from a temporarily created file in @var{path}.
 ETEXI
diff --git a/vl.c b/vl.c
index 1d27b34..08f9bee 100644
--- a/vl.c
+++ b/vl.c
@@ -136,6 +136,7 @@ static int display_remote;
 const char* keyboard_layout = NULL;
 ram_addr_t ram_size;
 const char *mem_path = NULL;
+unsigned long int mem_path_min_hpagesize;
 int mem_prealloc = 0; /* force preallocation of physical target memory */
 int nb_nics;
 NICInfo nd_table[MAX_NICS];
@@ -479,6 +480,22 @@ static QemuOptsList qemu_msg_opts = {
     },
 };
 
+static QemuOptsList qemu_mempath_opts = {
+    .name = "mem-path",
+    .implied_opt_name = "mem-path",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_mempath_opts.head),
+    .desc = {
+        {
+            .name = "mem-path",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "min-hpage-size",
+            .type = QEMU_OPT_SIZE,
+        },
+        { /* end of list */ }
+    },
+};
+
 /**
  * Get machine options
  *
@@ -2863,6 +2880,7 @@ int main(int argc, char **argv, char **envp)
     qemu_add_opts(&qemu_tpmdev_opts);
     qemu_add_opts(&qemu_realtime_opts);
     qemu_add_opts(&qemu_msg_opts);
+    qemu_add_opts(&qemu_mempath_opts);
 
     runstate_init();
 
@@ -3189,9 +3207,16 @@ int main(int argc, char **argv, char **envp)
                 }
                 break;
 #endif
-            case QEMU_OPTION_mempath:
-                mem_path = optarg;
+            case QEMU_OPTION_mempath: {
+                opts = qemu_opts_parse(qemu_find_opts("mem-path"), optarg, 1);
+                if (!opts) {
+                    exit(1);
+                }
+                mem_path = qemu_opt_get(opts, "mem-path");
+                mem_path_min_hpagesize = qemu_opt_get_size(opts,
+                                                           "min-hpage-size", 0);
                 break;
+            }
             case QEMU_OPTION_mem_prealloc:
                 mem_prealloc = 1;
                 break;