Patchwork [09/16] virtio-pci: support host notifiers in TCG mode

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Submitter Zhiyong Wu
Date April 19, 2012, 2:39 a.m.
Message ID <1334803149-27379-10-git-send-email-zwu.kernel@gmail.com>
Download mbox | patch
Permalink /patch/153631/
State New
Headers show

Comments

Zhiyong Wu - April 19, 2012, 2:39 a.m.
From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

Normally host notifiers are only used together with vhost-net in KVM
mode.  It is occassionally useful to use vhost with TCG mode, mainly for
testing and development.  This isn't hard to achieve, simply fall back
to notifying the host notifier manually from qemu if KVM mode is
disabled.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 hw/virtio-pci.c |   23 ++++++++++++++++++++---
 hw/virtio.c     |    7 +++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

Patch

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 4a4413d..dcd58d0 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -281,6 +281,25 @@  void virtio_pci_reset(DeviceState *d)
     proxy->flags &= ~VIRTIO_PCI_FLAG_BUS_MASTER_BUG;
 }
 
+static void virtio_pci_queue_notify(VirtIOPCIProxy *proxy, uint32_t n)
+{
+    VirtQueue *vq;
+    EventNotifier *notifier;
+
+    if (n >= VIRTIO_PCI_QUEUE_MAX) {
+        return;
+    }
+
+    vq = virtio_get_queue(proxy->vdev, n);
+    notifier = virtio_queue_get_host_notifier(vq);
+    if (event_notifier_valid(notifier)) {
+        printf("notifying vq %u host notifier from userspace\n", n);
+        event_notifier_notify(notifier);
+    } else {
+        virtio_queue_notify_vq(vq);
+    }
+}
+
 static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     VirtIOPCIProxy *proxy = opaque;
@@ -310,9 +329,7 @@  static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
             vdev->queue_sel = val;
         break;
     case VIRTIO_PCI_QUEUE_NOTIFY:
-        if (val < VIRTIO_PCI_QUEUE_MAX) {
-            virtio_queue_notify(vdev, val);
-        }
+        virtio_pci_queue_notify(proxy, val);
         break;
     case VIRTIO_PCI_STATUS:
         if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) {
diff --git a/hw/virtio.c b/hw/virtio.c
index 064aecf..e491850 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -527,6 +527,11 @@  void virtio_reset(void *opaque)
         vdev->vq[i].signalled_used = 0;
         vdev->vq[i].signalled_used_valid = false;
         vdev->vq[i].notification = true;
+
+        assert(!event_notifier_valid(&vdev->vq[i].guest_notifier));
+        assert(!event_notifier_valid(&vdev->vq[i].host_notifier));
+        vdev->vq[i].guest_notifier = EVENT_NOTIFIER_INITIALIZER;
+        vdev->vq[i].host_notifier = EVENT_NOTIFIER_INITIALIZER;
     }
 }
 
@@ -887,6 +892,8 @@  VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
     for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
         vdev->vq[i].vector = VIRTIO_NO_VECTOR;
         vdev->vq[i].vdev = vdev;
+        vdev->vq[i].guest_notifier = EVENT_NOTIFIER_INITIALIZER;
+        vdev->vq[i].host_notifier = EVENT_NOTIFIER_INITIALIZER;
     }
 
     vdev->name = name;