diff mbox series

[v6,05/15] virtio-pci: support queue reset

Message ID 20221017092558.111082-6-xuanzhuo@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series Support VIRTIO_F_RING_RESET for virtio-net, vhost-net kernel in virtio pci-modern | expand

Commit Message

Xuan Zhuo Oct. 17, 2022, 9:25 a.m. UTC 
PCI devices support vq reset.

Based on this function, the driver can adjust the size of the ring, and
quickly recycle the buffer in the ring.

The migration of the virtio devices will not happen during a reset
operation. This is becuase the global iothread lock is held. Migration
thread also needs the lock. As a result, when migration of virtio
devices starts, the 'reset' status of VirtIOPCIQueue will always be 0.
Thus, we do not need to add it in vmstate_virtio_pci_modern_queue_state.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio-pci.c         | 15 +++++++++++++++
 include/hw/virtio/virtio-pci.h |  5 +++++
 2 files changed, 20 insertions(+)
diff mbox series

Patch

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index e7d80242b7..a41c1dfe71 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1251,6 +1251,9 @@  static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
     case VIRTIO_PCI_COMMON_Q_USEDHI:
         val = proxy->vqs[vdev->queue_sel].used[1];
         break;
+    case VIRTIO_PCI_COMMON_Q_RESET:
+        val = proxy->vqs[vdev->queue_sel].reset;
+        break;
     default:
         val = 0;
     }
@@ -1338,6 +1341,7 @@  static void virtio_pci_common_write(void *opaque, hwaddr addr,
                        ((uint64_t)proxy->vqs[vdev->queue_sel].used[1]) << 32 |
                        proxy->vqs[vdev->queue_sel].used[0]);
             proxy->vqs[vdev->queue_sel].enabled = 1;
+            proxy->vqs[vdev->queue_sel].reset = 0;
         } else {
             virtio_error(vdev, "wrong value for queue_enable %"PRIx64, val);
         }
@@ -1360,6 +1364,16 @@  static void virtio_pci_common_write(void *opaque, hwaddr addr,
     case VIRTIO_PCI_COMMON_Q_USEDHI:
         proxy->vqs[vdev->queue_sel].used[1] = val;
         break;
+    case VIRTIO_PCI_COMMON_Q_RESET:
+        if (val == 1) {
+            proxy->vqs[vdev->queue_sel].reset = 1;
+
+            virtio_queue_reset(vdev, vdev->queue_sel);
+
+            proxy->vqs[vdev->queue_sel].reset = 0;
+            proxy->vqs[vdev->queue_sel].enabled = 0;
+        }
+        break;
     default:
         break;
     }
@@ -1954,6 +1968,7 @@  static void virtio_pci_reset(DeviceState *qdev)
 
     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
         proxy->vqs[i].enabled = 0;
+        proxy->vqs[i].reset = 0;
         proxy->vqs[i].num = 0;
         proxy->vqs[i].desc[0] = proxy->vqs[i].desc[1] = 0;
         proxy->vqs[i].avail[0] = proxy->vqs[i].avail[1] = 0;
diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
index 2446dcd9ae..938799e8f6 100644
--- a/include/hw/virtio/virtio-pci.h
+++ b/include/hw/virtio/virtio-pci.h
@@ -117,6 +117,11 @@  typedef struct VirtIOPCIRegion {
 typedef struct VirtIOPCIQueue {
   uint16_t num;
   bool enabled;
+  /*
+   * No need to migrate the reset status, because it is always 0
+   * when the migration starts.
+   */
+  bool reset;
   uint32_t desc[2];
   uint32_t avail[2];
   uint32_t used[2];