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[Qemu-devel] [PATCH 5/9] virtio: add aio handler
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 5/9] virtio: add aio handler |
Date: |
Wed, 30 Mar 2016 14:48:04 +0200 |
From: "Michael S. Tsirkin" <address@hidden>
In addition to handling IO in vcpu thread and
in io thread, blk dataplane introduces yet another mode:
handling it by aio.
This reuses the same handler as previous modes,
which triggers races as these were not designed to be reentrant.
As a temporary fix, add a separate handler just for aio, this will make
it possible to disable regular handlers when dataplane is active.
Signed-off-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/virtio/virtio.c | 36 ++++++++++++++++++++++++++++++++----
include/hw/virtio/virtio.h | 3 +++
2 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 07c45b6..39a9f47 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -94,6 +94,7 @@ struct VirtQueue
uint16_t vector;
void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
+ void (*handle_aio_output)(VirtIODevice *vdev, VirtQueue *vq);
VirtIODevice *vdev;
EventNotifier guest_notifier;
EventNotifier host_notifier;
@@ -1086,6 +1087,16 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n,
int align)
virtio_queue_update_rings(vdev, n);
}
+static void virtio_queue_notify_aio_vq(VirtQueue *vq)
+{
+ if (vq->vring.desc && vq->handle_aio_output) {
+ VirtIODevice *vdev = vq->vdev;
+
+ trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
+ vq->handle_aio_output(vdev, vq);
+ }
+}
+
static void virtio_queue_notify_vq(VirtQueue *vq)
{
if (vq->vring.desc && vq->handle_output) {
@@ -1141,10 +1152,19 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int
queue_size,
vdev->vq[i].vring.num_default = queue_size;
vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
vdev->vq[i].handle_output = handle_output;
+ vdev->vq[i].handle_aio_output = NULL;
return &vdev->vq[i];
}
+void virtio_set_queue_aio(VirtQueue *vq,
+ void (*handle_output)(VirtIODevice *, VirtQueue *))
+{
+ assert(vq->handle_output);
+
+ vq->handle_aio_output = handle_output;
+}
+
void virtio_del_queue(VirtIODevice *vdev, int n)
{
if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
@@ -1778,11 +1798,11 @@ EventNotifier
*virtio_queue_get_guest_notifier(VirtQueue *vq)
return &vq->guest_notifier;
}
-static void virtio_queue_host_notifier_read(EventNotifier *n)
+static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
{
VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
if (event_notifier_test_and_clear(n)) {
- virtio_queue_notify_vq(vq);
+ virtio_queue_notify_aio_vq(vq);
}
}
@@ -1791,14 +1811,22 @@ void
virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
{
if (assign && set_handler) {
aio_set_event_notifier(ctx, &vq->host_notifier, true,
- virtio_queue_host_notifier_read);
+ virtio_queue_host_notifier_aio_read);
} else {
aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL);
}
if (!assign) {
/* Test and clear notifier before after disabling event,
* in case poll callback didn't have time to run. */
- virtio_queue_host_notifier_read(&vq->host_notifier);
+ virtio_queue_host_notifier_aio_read(&vq->host_notifier);
+ }
+}
+
+static void virtio_queue_host_notifier_read(EventNotifier *n)
+{
+ VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
+ if (event_notifier_test_and_clear(n)) {
+ virtio_queue_notify_vq(vq);
}
}
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 5afb51c..fa3f93b 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -142,6 +142,9 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int
queue_size,
void (*handle_output)(VirtIODevice *,
VirtQueue *));
+void virtio_set_queue_aio(VirtQueue *vq,
+ void (*handle_output)(VirtIODevice *, VirtQueue *));
+
void virtio_del_queue(VirtIODevice *vdev, int n);
void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num);
--
1.8.3.1
- [Qemu-devel] [PATCH resend 0/9] virtio: aio handler API, Paolo Bonzini, 2016/03/30
- [Qemu-devel] [PATCH 4/9] virtio-scsi: fix disabled mode, Paolo Bonzini, 2016/03/30
- [Qemu-devel] [PATCH 5/9] virtio: add aio handler,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 2/9] virtio: make virtio_queue_notify_vq static, Paolo Bonzini, 2016/03/30
- [Qemu-devel] [PATCH 6/9] virtio-blk: use aio handler for data plane, Paolo Bonzini, 2016/03/30
- [Qemu-devel] [PATCH 7/9] virtio-scsi: use aio handler for data plane, Paolo Bonzini, 2016/03/30
- [Qemu-devel] [PATCH 8/9] virtio: merge virtio_queue_aio_set_host_notifier_handler with virtio_queue_set_aio, Paolo Bonzini, 2016/03/30