Monitor commands "hostcache_set" and "hostcache_get" added for dynamic
host cache change and display of host cache setting respectively.
Signed-off-by: Supriya Kannery <supri...@in.ibm.com>
---
block.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
block.h | 2 ++
blockdev.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
blockdev.h | 2 ++
hmp-commands.hx | 29 +++++++++++++++++++++++++++++
qmp-commands.hx | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 184 insertions(+)
Index: qemu/hmp-commands.hx
===================================================================
--- qemu.orig/hmp-commands.hx
+++ qemu/hmp-commands.hx
@@ -70,6 +70,35 @@ but should be used with extreme caution.
resizes image files, it can not resize block devices like LVM volumes.
ETEXI
+ {
+ .name = "hostcache_get",
+ .args_type = "device:B",
+ .params = "device",
+ .help = "retrieve host cache settings for device",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_hostcache_get,
+ },
+
+STEXI
+@item hostcache_get
+@findex hostcache_get
+Display host cache settings for a block device while guest is running.
+ETEXI
+
+ {
+ .name = "hostcache_set",
+ .args_type = "device:B,hostcache:s",
+ .params = "device hostcache",
+ .help = "change host cache setting for device",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_hostcache_set,
+ },
+
+STEXI
+@item hostcache_set
+@findex hostcache_set
+Change host cache options for a block device while guest is running.
+ETEXI
{
.name = "eject",
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c
+++ qemu/block.c
@@ -657,6 +657,34 @@ unlink_and_fail:
return ret;
}
+int bdrv_reopen(BlockDriverState *bs, int bdrv_flags)
+{
+ BlockDriver *drv = bs->drv;
+ int ret = 0;
+
+ /* No need to reopen as no change in flags */
+ if (bdrv_flags == bs->open_flags) {
+ return 0;
+ }
+
+ /* Quiesce IO for the given block device */
+ qemu_aio_flush();
+ bdrv_flush(bs);
+
+ bdrv_close(bs);
+ ret = bdrv_open(bs, bs->filename, bdrv_flags, drv);
+
+ /*
+ * A failed attempt to reopen the image file must lead to 'abort()'
+ */
+ if (ret != 0) {
+ qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename);
+ abort();
+ }
+
+ return ret;
+}
+
void bdrv_close(BlockDriverState *bs)
{
if (bs->drv) {
@@ -3049,3 +3077,23 @@ out:
return ret;
}
+
+int bdrv_change_hostcache(BlockDriverState *bs, bool enable_host_cache)
+{
+ int bdrv_flags = bs->open_flags;
+
+ /* No change in existing hostcache setting */
+ if(!enable_host_cache == (bdrv_flags & BDRV_O_NOCACHE)) {
+ return -1;
+ }
+
+ /* set hostcache flags (without changing WCE/flush bits) */
+ if(!enable_host_cache) {
+ bdrv_flags |= BDRV_O_NOCACHE;
+ } else {
+ bdrv_flags &= ~BDRV_O_NOCACHE;
+ }
+
+ /* Reopen file with changed set of flags */
+ return(bdrv_reopen(bs, bdrv_flags));
+}
Index: qemu/blockdev.c
===================================================================
--- qemu.orig/blockdev.c
+++ qemu/blockdev.c
@@ -796,3 +796,51 @@ int do_block_resize(Monitor *mon, const
return 0;
}
+
+int do_hostcache_get(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+ const char *device = qdict_get_str(qdict, "device");
+ BlockDriverState *bs;
+
+ bs = bdrv_find(device);
+ if (!bs) {
+ qerror_report(QERR_DEVICE_NOT_FOUND, device);
+ return -1;
+ }
+
+ monitor_printf(mon, "%s:", device);
+
+ if (bs->open_flags & BDRV_O_NOCACHE) {
+ monitor_printf(mon, " hostcache=off\n");
+ } else {
+ monitor_printf(mon, " hostcache=on\n");
+ }
+
+ return 0;
+}
+
+int do_hostcache_set(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+ const char *device = qdict_get_str(qdict, "device");
+ const char *hostcache = qdict_get_str(qdict, "hostcache");
+ BlockDriverState *bs;
+ bool enable_host_cache = 0;
+
+ bs = bdrv_find(device);
+ if (!bs) {
+ qerror_report(QERR_DEVICE_NOT_FOUND, device);
+ return -1;
+ }
+
+ /* cache change applicable only if device inserted */
+ if (bdrv_is_inserted(bs)) {
+ if (!strcmp(hostcache,"on"))
+ enable_host_cache = 1;
+ else
+ enable_host_cache = 0;
+ return(bdrv_change_hostcache(bs, enable_host_cache));
+ } else {
+ qerror_report(QERR_DEVICE_NOT_INSERTED, device);
+ return -1;
+ }
+}
Index: qemu/block.h
===================================================================
--- qemu.orig/block.h
+++ qemu/block.h
@@ -71,6 +71,7 @@ void bdrv_delete(BlockDriverState *bs);
int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
BlockDriver *drv);
+int bdrv_reopen(BlockDriverState *bs, int bdrv_flags);
void bdrv_close(BlockDriverState *bs);
int bdrv_attach(BlockDriverState *bs, DeviceState *qdev);
void bdrv_detach(BlockDriverState *bs, DeviceState *qdev);
@@ -96,6 +97,7 @@ void bdrv_commit_all(void);
int bdrv_change_backing_file(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt);
void bdrv_register(BlockDriver *bdrv);
+int bdrv_change_hostcache(BlockDriverState *bs, bool enable_host_cache);
typedef struct BdrvCheckResult {
Index: qemu/blockdev.h
===================================================================
--- qemu.orig/blockdev.h
+++ qemu/blockdev.h
@@ -64,5 +64,7 @@ int do_change_block(Monitor *mon, const
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data);
int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data);
+int do_hostcache_get(Monitor *mon, const QDict *qdict, QObject **ret_data);
+int do_hostcache_set(Monitor *mon, const QDict *qdict, QObject **ret_data);
#endif
Index: qemu/qmp-commands.hx
===================================================================
--- qemu.orig/qmp-commands.hx
+++ qemu/qmp-commands.hx
@@ -664,6 +664,61 @@ Example:
-> { "execute": "block_resize", "arguments": { "device": "scratch", "size":
1073741824 } }
<- { "return": {} }
+
+EQMP
+
+ {
+ .name = "hostcache_get",
+ .args_type = "device:B",
+ .params = "device",
+ .help = "retrieve host cache settings for device",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_hostcache_get,
+ },
+SQMP
+cache_get
+---------
+
+Retrieve host page cache setting while a guest is running.
+
+Arguments:
+
+- "device": the device's ID, must be unique (json-string)
+
+Example:
+
+-> { "execute": "hostcache_set", "arguments": { "device": "ide0-hd0" } }
+<- { "return": {} }
+
+
+EQMP
+
+ {
+ .name = "hostcache_set",
+ .args_type = "device:B,cache:s",
+ .params = "device cache",
+ .help = "change hostcache setting for device",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_hostcache_set,
+ },
+
+SQMP
+hostcache_set
+-------------
+
+Change host page cache setting while a guest is running.
+
+Arguments:
+
+- "device": the device's ID, must be unique (json-string)
+- "cache": host cache value "off" or "on" (json-string)
+
+Example:
+
+-> { "execute": "hostcache_set", "arguments": { "device": "ide0-hd0", "cache":
"on" } }
+<- { "return": {} }
+
+
EQMP
{
