Re: [PATCH 06/16] virtio-pci: support queue reset

[Jason Wang]

在 2022/7/18 19:17, Kangjie Xu 写道:

From: Xuan Zhuo <xuanz...@linux.alibaba.com>

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.

Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
  hw/virtio/virtio-pci.c         | 16 ++++++++++++++++
  include/hw/virtio/virtio-pci.h |  1 +
  2 files changed, 17 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 45327f0b31..35e8a5101a 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1246,6 +1246,9 @@ 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;
      }
@@ -1333,6 +1336,7 @@ 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);
          }
@@ -1355,6 +1359,17 @@ 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);
+
+            /* mark reset complete */

The code explain itself, so the comment could be removed.

+            proxy->vqs[vdev->queue_sel].reset = 0;
+            proxy->vqs[vdev->queue_sel].enabled = 0;
+        }
+        break;
      default:
          break;
      }
@@ -1950,6 +1965,7 @@ 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..e9290e2b94 100644
--- a/include/hw/virtio/virtio-pci.h
+++ b/include/hw/virtio/virtio-pci.h
@@ -117,6 +117,7 @@ typedef struct VirtIOPCIRegion {
  typedef struct VirtIOPCIQueue {
    uint16_t num;
    bool enabled;
+  bool reset;

How is this migrated?

Thanks

    uint32_t desc[2];
    uint32_t avail[2];
    uint32_t used[2];