[Qemu-devel] [PATCH v2 0/2] dataplane: Enable config-wce

[Qemu-devel] [PATCH v2 0/2] dataplane: Enable config-wce

[Fam Zheng]

This applies on top of Stefan's dataplane series.

v2:

Patch 1 moves the declaration of bdrv_get_aio_context to block.h.
Patch 2 is unchanged except for the dropped #include.


Fam Zheng (2):
  block: Move declaration of bdrv_get_aio_context to block.h
  virtio-blk: Allow config-wce in dataplane

 hw/block/dataplane/virtio-blk.c | 6 ------
 hw/block/virtio-blk.c           | 8 +++++++-
 include/block/block.h           | 7 +++++++
 include/block/block_int.h       | 7 -------
 4 files changed, 14 insertions(+), 14 deletions(-)

-- 
1.9.2

[Qemu-devel] [PATCH v2 1/2] block: Move declaration of bdrv_get_aio_context to block.h

[Fam Zheng]

block_int.h is for block layer and block drivers, other code shouldn't
include it. But similar to bdrv_set_aio_context, bdrv_get_aio_context
should also be accessible from outside of block layer.

Move it.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 include/block/block.h     | 7 +++++++
 include/block/block_int.h | 7 -------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index d223e33..6676d1f 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -534,6 +534,13 @@ int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 
 /**
+ * bdrv_get_aio_context:
+ *
+ * Returns: the currently bound #AioContext
+ */
+AioContext *bdrv_get_aio_context(BlockDriverState *bs);
+
+/**
  * bdrv_set_aio_context:
  *
  * Changes the #AioContext used for fd handlers, timers, and BHs by this
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 47c79b3..a9301d5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -397,13 +397,6 @@ void bdrv_add_before_write_notifier(BlockDriverState *bs,
                                     NotifierWithReturn *notifier);
 
 /**
- * bdrv_get_aio_context:
- *
- * Returns: the currently bound #AioContext
- */
-AioContext *bdrv_get_aio_context(BlockDriverState *bs);
-
-/**
  * bdrv_detach_aio_context:
  *
  * May be called from .bdrv_detach_aio_context() to detach children from the
-- 
1.9.2

[Qemu-devel] [PATCH v2 2/2] virtio-blk: Allow config-wce in dataplane

[Fam Zheng]

Dataplane now uses block layer. Protect bdrv_set_enable_write_cache with
aio_context_acquire and aio_context_release, so we can enable config-wce
to allow guest to modify the write cache online.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 hw/block/dataplane/virtio-blk.c | 6 ------
 hw/block/virtio-blk.c           | 8 +++++++-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 79fb612..46a6824 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -332,12 +332,6 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
         return;
     }
 
-    if (blk->config_wce) {
-        error_setg(errp, "device is incompatible with x-data-plane, "
-                         "use config-wce=off");
-        return;
-    }
-
     /* If dataplane is (re-)enabled while the guest is running there could be
      * block jobs that can conflict.
      */
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 8a568e5..5e9433d 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -523,7 +523,10 @@ static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
     struct virtio_blk_config blkcfg;
 
     memcpy(&blkcfg, config, sizeof(blkcfg));
+
+    aio_context_acquire(bdrv_get_aio_context(s->bs));
     bdrv_set_enable_write_cache(s->bs, blkcfg.wce != 0);
+    aio_context_release(bdrv_get_aio_context(s->bs));
 }
 
 static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
@@ -582,7 +585,10 @@ static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
      * s->bs would erroneously be placed in writethrough mode.
      */
     if (!(features & (1 << VIRTIO_BLK_F_CONFIG_WCE))) {
-        bdrv_set_enable_write_cache(s->bs, !!(features & (1 << VIRTIO_BLK_F_WCE)));
+        aio_context_acquire(bdrv_get_aio_context(s->bs));
+        bdrv_set_enable_write_cache(s->bs,
+                                    !!(features & (1 << VIRTIO_BLK_F_WCE)));
+        aio_context_release(bdrv_get_aio_context(s->bs));
     }
 }
 
-- 
1.9.2

Re: [Qemu-devel] [PATCH v2 0/2] dataplane: Enable config-wce

[Paolo Bonzini]

Il 15/05/2014 13:22, Fam Zheng ha scritto:
> This applies on top of Stefan's dataplane series.
>
> v2:
>
> Patch 1 moves the declaration of bdrv_get_aio_context to block.h.
> Patch 2 is unchanged except for the dropped #include.
>
>
> Fam Zheng (2):
>   block: Move declaration of bdrv_get_aio_context to block.h
>   virtio-blk: Allow config-wce in dataplane
>
>  hw/block/dataplane/virtio-blk.c | 6 ------
>  hw/block/virtio-blk.c           | 8 +++++++-
>  include/block/block.h           | 7 +++++++
>  include/block/block_int.h       | 7 -------
>  4 files changed, 14 insertions(+), 14 deletions(-)
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [Qemu-devel] [PATCH v2 0/2] dataplane: Enable config-wce

[Stefan Hajnoczi]

On Thu, May 15, 2014 at 07:22:04PM +0800, Fam Zheng wrote:
> This applies on top of Stefan's dataplane series.
> 
> v2:
> 
> Patch 1 moves the declaration of bdrv_get_aio_context to block.h.
> Patch 2 is unchanged except for the dropped #include.
> 
> 
> Fam Zheng (2):
>   block: Move declaration of bdrv_get_aio_context to block.h
>   virtio-blk: Allow config-wce in dataplane
> 
>  hw/block/dataplane/virtio-blk.c | 6 ------
>  hw/block/virtio-blk.c           | 8 +++++++-
>  include/block/block.h           | 7 +++++++
>  include/block/block_int.h       | 7 -------
>  4 files changed, 14 insertions(+), 14 deletions(-)
> 
> -- 
> 1.9.2
> 

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Re: [Qemu-devel] [PATCH v2 0/2] dataplane: Enable config-wce

[Stefan Hajnoczi]

On Thu, May 15, 2014 at 07:22:04PM +0800, Fam Zheng wrote:
> This applies on top of Stefan's dataplane series.
> 
> v2:
> 
> Patch 1 moves the declaration of bdrv_get_aio_context to block.h.
> Patch 2 is unchanged except for the dropped #include.
> 
> 
> Fam Zheng (2):
>   block: Move declaration of bdrv_get_aio_context to block.h
>   virtio-blk: Allow config-wce in dataplane
> 
>  hw/block/dataplane/virtio-blk.c | 6 ------
>  hw/block/virtio-blk.c           | 8 +++++++-
>  include/block/block.h           | 7 +++++++
>  include/block/block_int.h       | 7 -------
>  4 files changed, 14 insertions(+), 14 deletions(-)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan