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[Qemu-devel] [RFC v2 1/3] virtio: add vdc->vmchange_state() callback
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [RFC v2 1/3] virtio: add vdc->vmchange_state() callback |
Date: |
Thu, 23 May 2019 14:44:07 +0100 |
The core virtio code invokes ->set_status() followed by
->ioeventfd_start() when the guest resumes execution. Both of these
functions are also called in other cases unrelated to vm change state.
This patch introduces ->vmstate_change() so that devices can act on
guest pause/resume. The existing qemu_add_vm_change_state_handler() API
isn't usable by virtio devices since the ordering between vm change
state handlers is undefined. The new ->vmstate_change() callback is
always invoked after ->set_status() and ->ioeventfd_start() when
resuming a guest.
A later patch makes use of this new callback.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
include/hw/virtio/virtio.h | 7 +++++++
hw/virtio/virtio.c | 9 +++++++++
2 files changed, 16 insertions(+)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 7140381e3a..46e54362dc 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -156,6 +156,13 @@ typedef struct VirtioDeviceClass {
void (*save)(VirtIODevice *vdev, QEMUFile *f);
int (*load)(VirtIODevice *vdev, QEMUFile *f, int version_id);
const VMStateDescription *vmsd;
+
+ /* Called when the device should start/stop running because the guest was
+ * resumed/paused. Note that this takes VIRTIO_CONFIG_S_DRIVER_OK into
+ * account so running is true iff the guest is resumed and the guest driver
+ * has already indicated it is ready.
+ */
+ void (*vmstate_change)(VirtIODevice *vdev, bool running);
} VirtioDeviceClass;
void virtio_instance_init_common(Object *proxy_obj, void *data,
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 28056a7ef7..f9f31b5325 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2246,6 +2246,7 @@ static void virtio_vmstate_change(void *opaque, int
running, RunState state)
VirtIODevice *vdev = opaque;
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+ VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
vdev->vm_running = running;
@@ -2253,10 +2254,18 @@ static void virtio_vmstate_change(void *opaque, int
running, RunState state)
virtio_set_status(vdev, vdev->status);
}
+ if (!backend_run && k->vmstate_change) {
+ vdc->vmstate_change(vdev, backend_run);
+ }
+
if (k->vmstate_change) {
k->vmstate_change(qbus->parent, backend_run);
}
+ if (backend_run && k->vmstate_change) {
+ vdc->vmstate_change(vdev, backend_run);
+ }
+
if (!backend_run) {
virtio_set_status(vdev, vdev->status);
}
--
2.21.0