From ac48d782f3b91b2e9962ded5f8a55bd3929a82a5 Mon Sep 17 00:00:00 2001
From: Michael S. Tsirkin <mst@redhat.com>
Date: Wed, 24 Feb 2010 21:09:54 +0200
Subject: [PATCH] vhost: used addr migration fix

Enable used buffer logging when migration starts.
Fixed 'id XX is not a head' message after migration.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/vhost.c |   29 +++++++++++++++++++++++++++--
 1 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/hw/vhost.c b/hw/vhost.c
index 54386e1..48034ba 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -325,7 +325,7 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
 	return 0;
 }

-static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
+static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
 {
 	uint64_t features = dev->acked_features;
 	int r;
@@ -336,6 +336,31 @@ static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 	return r < 0 ? -errno : 0;
 }

+static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
+{
+	int r, t, i;
+	r = vhost_dev_set_features(dev, enable_log);
+	if (r < 0)
+		goto err_features;
+	for (i = 0; i < dev->nvqs; ++i) {
+		r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
+					     enable_log);
+		if (r < 0)
+			goto err_vq;
+	}
+	return 0;
+err_vq:
+	for (; i >= 0; --i) {
+		t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
+					     dev->log_enabled);
+		assert(t >= 0);
+	}
+	t = vhost_dev_set_features(dev, dev->log_enabled);
+	assert(t >= 0);
+err_features:
+	return r;
+}
+
 static int vhost_client_migration_log(struct CPUPhysMemoryClient *client,
 				      int enable)
 {
@@ -544,7 +569,7 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 {
 	int i, r;

-	r = vhost_dev_set_log(hdev, hdev->log_enabled);
+	r = vhost_dev_set_features(hdev, hdev->log_enabled);
 	if (r < 0)
 		goto fail;
 	r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
-- 
1.6.6.1