[Qemu-block] [PATCH 1/3] hw/block: Introduce rotational qdev property

[Aurelien Jarno]

The Linux kernel uses different I/O scheduler depending if the block
device is a rotational device or not. Also it uses rotational devices
to add entropy to the random pool.

This patch add a rotational qdev property so that the block device can
be configured as a rotational device or a non-rotational device. Default
to true to not change the default behavior.

Signed-off-by: Aurelien Jarno <address@hidden>
---
 blockdev.c               | 4 ++++
 include/hw/block/block.h | 4 +++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index 4d8cdedd54..c914420641 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -4037,6 +4037,10 @@ QemuOptsList qemu_common_drive_opts = {
             .name = BDRV_OPT_READ_ONLY,
             .type = QEMU_OPT_BOOL,
             .help = "open drive file as read-only",
+        },{
+            .name = "rotational",
+            .type = QEMU_OPT_BOOL,
+            .help = "rotational drive (off, on)",
         },
 
         THROTTLE_OPTS,
diff --git a/include/hw/block/block.h b/include/hw/block/block.h
index f3f6e8ef02..304a579eca 100644
--- a/include/hw/block/block.h
+++ b/include/hw/block/block.h
@@ -27,6 +27,7 @@ typedef struct BlockConf {
     uint32_t cyls, heads, secs;
     OnOffAuto wce;
     bool share_rw;
+    bool rotational;
     BlockdevOnError rerror;
     BlockdevOnError werror;
 } BlockConf;
@@ -56,7 +57,8 @@ static inline unsigned int get_physical_block_exp(BlockConf 
*conf)
                        _conf.discard_granularity, -1), \
     DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce, \
                             ON_OFF_AUTO_AUTO), \
-    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false)
+    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false), \
+    DEFINE_PROP_BOOL("rotational", _state, _conf.rotational, true)
 
 #define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf)      \
     DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0),  \
-- 
2.11.0