[Qemu-devel] [PATCH v2 21/24] block: Initial implementation of -blockdev

Markus Armbruster posted 24 patches 8 years, 11 months ago
There is a newer version of this series
[Qemu-devel] [PATCH v2 21/24] block: Initial implementation of -blockdev
Posted by Markus Armbruster 8 years, 11 months ago
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 or downstream extensions, i.e. keys
with __RFQDN_ prefix, but the next few patches will take care of that.

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>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 qemu-options.hx |  7 +++++++
 vl.c            | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index faf5cf8..7eacb54 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -532,6 +532,13 @@ 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 c6020b9..68405c6 100644
--- 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"
@@ -2975,6 +2978,13 @@ 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);
 
@@ -3117,6 +3127,25 @@ 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);
@@ -4450,6 +4479,16 @@ 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);
-- 
2.7.4


Re: [Qemu-devel] [PATCH v2 21/24] block: Initial implementation of -blockdev
Posted by Kevin Wolf 8 years, 11 months ago
Am 28.02.2017 um 22:27 hat Markus Armbruster geschrieben:
> 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 or downstream extensions, i.e. keys
> with __RFQDN_ prefix, but the next few patches will take care of that.
> 
> 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>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>

Double S-o-B? Anyway:

Reviewed-by: Kevin Wolf <kwolf@redhat.com>