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[Qemu-block] [PATCH 13/40] virtio-blk: fix "disabled data plane" mode
From: |
Paolo Bonzini |
Subject: |
[Qemu-block] [PATCH 13/40] virtio-blk: fix "disabled data plane" mode |
Date: |
Tue, 24 Nov 2015 19:01:04 +0100 |
In disabled mode, virtio-blk dataplane seems to be enabled, but flow
actually goes through the normal virtio path. This patch simplifies a bit
the handling of disabled mode. In disabled mode, virtio_blk_handle_output
might be called even if s->dataplane is not NULL.
This is a bit tricky, because the current check for s->dataplane will
always trigger, causing a continuous stream of calls to
virtio_blk_data_plane_start. Unfortunately, these calls will not
do anything. To fix this, set the "started" flag even in disabled
mode, and skip virtio_blk_data_plane_start if the started flag is true.
The resulting changes also prepare the code for the next patch, were
virtio-blk dataplane will reuse the same virtio_blk_handle_output function
as "regular" virtio-blk.
Because struct VirtIOBlockDataPlane is opaque in virtio-blk.c, we have
to move s->dataplane->started inside struct VirtIOBlock.
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/block/dataplane/virtio-blk.c | 21 +++++++++------------
hw/block/virtio-blk.c | 2 +-
include/hw/virtio/virtio-blk.h | 1 +
3 files changed, 11 insertions(+), 13 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index ace36f5..8d417e2 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -27,7 +27,6 @@
#include "qom/object_interfaces.h"
struct VirtIOBlockDataPlane {
- bool started;
bool starting;
bool stopping;
bool disabled;
@@ -237,11 +236,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
VirtQueue *vq;
int r;
- if (s->started || s->disabled) {
- return;
- }
-
- if (s->starting) {
+ if (vblk->dataplane_started || s->starting) {
return;
}
@@ -273,7 +268,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
vblk->complete_request = complete_request_vring;
s->starting = false;
- s->started = true;
+ vblk->dataplane_started = true;
trace_virtio_blk_data_plane_start(s);
blk_set_aio_context(s->conf->conf.blk, s->ctx);
@@ -292,9 +287,10 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
k->set_guest_notifiers(qbus->parent, 1, false);
fail_guest_notifiers:
vring_teardown(&s->vring, s->vdev, 0);
- s->disabled = true;
fail_vring:
+ s->disabled = true;
s->starting = false;
+ vblk->dataplane_started = true;
}
/* Context: QEMU global mutex held */
@@ -304,13 +300,14 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
+ if (!vblk->dataplane_started || s->stopping) {
+ return;
+ }
/* Better luck next time. */
if (s->disabled) {
s->disabled = false;
- return;
- }
- if (!s->started || s->stopping) {
+ vblk->dataplane_started = false;
return;
}
s->stopping = true;
@@ -337,6 +334,6 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
/* Clean up guest notifier (irq) */
k->set_guest_notifiers(qbus->parent, 1, false);
- s->started = false;
+ vblk->dataplane_started = false;
s->stopping = false;
}
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 773b61c..062d57e 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -596,7 +596,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* dataplane here instead of waiting for .set_status().
*/
- if (s->dataplane) {
+ if (s->dataplane && !s->dataplane_started) {
virtio_blk_data_plane_start(s->dataplane);
return;
}
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 9a2048d..e720934 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -57,6 +57,7 @@ typedef struct VirtIOBlock {
/* Function to push to vq and notify guest */
void (*complete_request)(struct VirtIOBlockReq *req, unsigned char status);
Notifier migration_state_notifier;
+ bool dataplane_started;
struct VirtIOBlockDataPlane *dataplane;
} VirtIOBlock;
--
1.8.3.1
- [Qemu-block] [PATCH 01/40] 9pfs: allocate pdus with g_malloc/g_free, (continued)
- [Qemu-block] [PATCH 01/40] 9pfs: allocate pdus with g_malloc/g_free, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 03/40] virtio: move allocation to virtqueue_pop/vring_pop, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 06/40] virtio: introduce virtqueue_alloc_element, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 04/40] virtio: introduce qemu_get/put_virtqueue_element, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 07/40] virtio: slim down allocation of VirtQueueElements, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 09/40] vring: make vring_enable_notification return void, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 08/40] vring: slim down allocation of VirtQueueElements, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 05/40] virtio: read/write the VirtQueueElement a field at a time, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 10/40] virtio: combine the read of a descriptor, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 12/40] virtio: export vring_notify as virtio_should_notify, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 13/40] virtio-blk: fix "disabled data plane" mode,
Paolo Bonzini <=
- [Qemu-block] [PATCH 14/40] virtio-blk: do not use vring in dataplane, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 11/40] virtio: add AioContext-specific function for host notifiers, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 15/40] virtio-scsi: do not use vring in dataplane, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 16/40] vring: remove, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 18/40] qemu-thread: introduce QemuRecMutex, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 17/40] iothread: release AioContext around aio_poll, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 20/40] aio: rename bh_lock to list_lock, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 19/40] aio: convert from RFifoLock to QemuRecMutex, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 22/40] aio: make ctx->list_lock a QemuLockCnt, subsuming ctx->walking_bh, Paolo Bonzini, 2015/11/24
- [Qemu-block] [PATCH 21/40] qemu-thread: introduce QemuLockCnt, Paolo Bonzini, 2015/11/24