block: Initial implementation of -blockdev

The new command line option -blockdev works like QMP command
blockdev-add.

The option argument may be given in JSON syntax, exactly as in QMP.
Example usage:

    -blockdev '{"node-name": "foo", "driver": "raw", "file": {"driver": "file", "filename": "foo.img"} }'

The JSON argument doesn't exactly blend into the existing option
syntax, so the traditional KEY=VALUE,... syntax is also supported,
using dotted keys to do the nesting:

    -blockdev node-name=foo,driver=raw,file.driver=file,file.filename=foo.img

This does not yet support lists, but that will be addressed shortly.

Note that calling qmp_blockdev_add() (say via qmp_marshal_block_add())
right away would crash.  We need to stash the configuration for later
instead.  This is crudely done, and bypasses QemuOpts, even though
storing configuration is what QemuOpts is for.  Need to revamp option
infrastructure to support QAPI types like BlockdevOptions.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488317230-26248-22-git-send-email-armbru@redhat.com>

diff --git a/qemu-options.hx b/qemu-options.hx
index 229243831b7ab3b684d31df5593849176851ab5c..8dd8ee34a6ac8d4303388d30808347d05a64166d 100644 (file)
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -550,6 +550,13 @@ Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
 using @file{/dev/cdrom} as filename (@pxref{host_drives}).
 ETEXI
 
+DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
+    "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
+    "          [,cache.direct=on|off][,cache.no-flush=on|off]\n"
+    "          [,read-only=on|off][,detect-zeroes=on|off|unmap]\n"
+    "          [,driver specific parameters...]\n"
+    "                configure a block backend\n", QEMU_ARCH_ALL)
+
 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
     "       [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"

diff --git a/vl.c b/vl.c
index 71b75ef8a07a1e300fa6d40a0176e817be96f295..7f1644a2be821b6ea540d061ba9afd670446e7a1 100644 (file)
--- a/vl.c
+++ b/vl.c
@@ -95,6 +95,9 @@ int main(int argc, char **argv)
 #include "migration/colo.h"
 #include "sysemu/kvm.h"
 #include "sysemu/hax.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi-visit.h"
 #include "qapi/qmp/qjson.h"
 #include "qemu/option.h"
 #include "qemu/config-file.h"
@@ -2976,6 +2979,13 @@ int main(int argc, char **argv, char **envp)
     Error *main_loop_err = NULL;
     Error *err = NULL;
     bool list_data_dirs = false;
+    typedef struct BlockdevOptions_queue {
+        BlockdevOptions *bdo;
+        Location loc;
+        QSIMPLEQ_ENTRY(BlockdevOptions_queue) entry;
+    } BlockdevOptions_queue;
+    QSIMPLEQ_HEAD(, BlockdevOptions_queue) bdo_queue
+        = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
 
     module_call_init(MODULE_INIT_TRACE);
 
@@ -3118,6 +3128,25 @@ int main(int argc, char **argv, char **envp)
                 drive_add(IF_DEFAULT, popt->index - QEMU_OPTION_hda, optarg,
                           HD_OPTS);
                 break;
+            case QEMU_OPTION_blockdev:
+                {
+                    Visitor *v;
+                    BlockdevOptions_queue *bdo;
+
+                    v = qobject_input_visitor_new_str(optarg, "driver", &err);
+                    if (!v) {
+                        error_report_err(err);
+                        exit(1);
+                    }
+
+                    bdo = g_new(BlockdevOptions_queue, 1);
+                    visit_type_BlockdevOptions(v, NULL, &bdo->bdo,
+                                               &error_fatal);
+                    visit_free(v);
+                    loc_save(&bdo->loc);
+                    QSIMPLEQ_INSERT_TAIL(&bdo_queue, bdo, entry);
+                    break;
+                }
             case QEMU_OPTION_drive:
                 if (drive_def(optarg) == NULL) {
                     exit(1);
@@ -4451,6 +4480,16 @@ int main(int argc, char **argv, char **envp)
     }
 
     /* open the virtual block devices */
+    while (!QSIMPLEQ_EMPTY(&bdo_queue)) {
+        BlockdevOptions_queue *bdo = QSIMPLEQ_FIRST(&bdo_queue);
+
+        QSIMPLEQ_REMOVE_HEAD(&bdo_queue, entry);
+        loc_push_restore(&bdo->loc);
+        qmp_blockdev_add(bdo->bdo, &error_fatal);
+        loc_pop(&bdo->loc);
+        qapi_free_BlockdevOptions(bdo->bdo);
+        g_free(bdo);
+    }
     if (snapshot || replay_mode != REPLAY_MODE_NONE) {
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
                           NULL, NULL);