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Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriat
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate |
Date: |
Wed, 1 Dec 2010 08:02:52 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Dec 01, 2010 at 01:45:09PM +0800, Jason Wang wrote:
> Michael S. Tsirkin writes:
> > Avoid sending out packets, and modifying
> > device state, when VM is stopped.
> > Add assert statements to verify this does not happen.
> >
> > Avoid scheduling bh when vhost-net is started.
> >
> > Stop bh when driver disabled bus mastering
> > (we must not access memory after this).
> >
> > Signed-off-by: Michael S. Tsirkin <address@hidden>
> >
>
> There's no need to disable it bh we call qemu_aio_flush() after
> vm_state_notify() in do_vm_stop(). And for timer, looks like every device
> should
> stop its timer in vm state change handler, not only for virtio-net?
BTW I fixed some typos. Here a fixed version.
Jason, could you review/test please?
virtio-net: stop/start bh when appropriate
Avoid sending out packets, and modifying
memory, when VM is stopped.
Add assert statements to verify this does not happen.
Avoid scheduling bh when vhost-net is started.
Stop bh when driver disabled bus mastering
(we must not access memory after this).
Signed-off-by: Michael S. Tsirkin <address@hidden>
Tested-by: Jason Wang <address@hidden>
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 43a2b3d..5881961 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -99,9 +99,14 @@ static void virtio_net_set_config(VirtIODevice *vdev, const
uint8_t *config)
}
}
-static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
+static bool virtio_net_started(VirtIONet *n, uint8_t status)
+{
+ return (status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+ (n->status & VIRTIO_NET_S_LINK_UP) && n->vm_running;
+}
+
+static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
{
- VirtIONet *n = to_virtio_net(vdev);
if (!n->nic->nc.peer) {
return;
}
@@ -112,9 +117,7 @@ static void virtio_net_set_status(struct VirtIODevice
*vdev, uint8_t status)
if (!tap_get_vhost_net(n->nic->nc.peer)) {
return;
}
- if (!!n->vhost_started == ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
- (n->status & VIRTIO_NET_S_LINK_UP) &&
- n->vm_running)) {
+ if (!!n->vhost_started == virtio_net_started(n, status)) {
return;
}
if (!n->vhost_started) {
@@ -131,6 +134,32 @@ static void virtio_net_set_status(struct VirtIODevice
*vdev, uint8_t status)
}
}
+static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
+{
+ VirtIONet *n = to_virtio_net(vdev);
+
+ virtio_net_vhost_status(n, status);
+
+ if (!n->tx_waiting) {
+ return;
+ }
+
+ if (virtio_net_started(n, status) && !n->vhost_started) {
+ if (n->tx_timer) {
+ qemu_mod_timer(n->tx_timer,
+ qemu_get_clock(vm_clock) + n->tx_timeout);
+ } else {
+ qemu_bh_schedule(n->tx_bh);
+ }
+ } else {
+ if (n->tx_timer) {
+ qemu_del_timer(n->tx_timer);
+ } else {
+ qemu_bh_cancel(n->tx_bh);
+ }
+ }
+}
+
static void virtio_net_set_link_status(VLANClientState *nc)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
@@ -675,11 +704,12 @@ static int32_t virtio_net_flush_tx(VirtIONet *n,
VirtQueue *vq)
{
VirtQueueElement elem;
int32_t num_packets = 0;
-
if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return num_packets;
}
+ assert(n->vm_running);
+
if (n->async_tx.elem.out_num) {
virtio_queue_set_notification(n->tx_vq, 0);
return num_packets;
@@ -738,6 +768,12 @@ static void virtio_net_handle_tx_timer(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
+ /* This happens when device was stopped but VCPU wasn't. */
+ if (!n->vm_running) {
+ n->tx_waiting = 1;
+ return;
+ }
+
if (n->tx_waiting) {
virtio_queue_set_notification(vq, 1);
qemu_del_timer(n->tx_timer);
@@ -758,14 +794,19 @@ static void virtio_net_handle_tx_bh(VirtIODevice *vdev,
VirtQueue *vq)
if (unlikely(n->tx_waiting)) {
return;
}
+ n->tx_waiting = 1;
+ /* This happens when device was stopped but VCPU wasn't. */
+ if (!n->vm_running) {
+ return;
+ }
virtio_queue_set_notification(vq, 0);
qemu_bh_schedule(n->tx_bh);
- n->tx_waiting = 1;
}
static void virtio_net_tx_timer(void *opaque)
{
VirtIONet *n = opaque;
+ assert(n->vm_running);
n->tx_waiting = 0;
@@ -782,6 +823,8 @@ static void virtio_net_tx_bh(void *opaque)
VirtIONet *n = opaque;
int32_t ret;
+ assert(n->vm_running);
+
n->tx_waiting = 0;
/* Just in case the driver is not ready on more */
@@ -926,15 +969,6 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int
version_id)
}
}
n->mac_table.first_multi = i;
-
- if (n->tx_waiting) {
- if (n->tx_timer) {
- qemu_mod_timer(n->tx_timer,
- qemu_get_clock(vm_clock) + n->tx_timeout);
- } else {
- qemu_bh_schedule(n->tx_bh);
- }
- }
return 0;
}
- [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Jason Wang, 2010/12/01
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Michael S. Tsirkin, 2010/12/01
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Jason Wang, 2010/12/01
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Jason Wang, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Michael S. Tsirkin, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Michael S. Tsirkin, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Jason Wang, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Michael S. Tsirkin, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Jason Wang, 2010/12/03
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Michael S. Tsirkin, 2010/12/02
- Re: [Qemu-devel] [PATCHv3 4/6] virtio-net: stop/start bh when appropriate, Kevin Wolf, 2010/12/03