Re: [PATCH v8 8/9] virtio-pci:decouple the single vector from the interrupt process

[Jason Wang]

在 2021/7/6 下午3:20, Cindy Lu 写道:

use the kvm_virtio_pci_vector_use_one and _release_one
these funtion is to deal with the single vector, the
whole process will finish in a loop with vq number.

Signed-off-by: Cindy Lu <l...@redhat.com>
---
  hw/virtio/virtio-pci.c | 109 ++++++++++++++++-------------------------
  1 file changed, 42 insertions(+), 67 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index fe06847b62..e43d5760ee 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -666,7 +666,6 @@ static uint32_t virtio_read_config(PCIDevice *pci_dev,
  }

static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,

-                                        unsigned int queue_no,
                                          unsigned int vector)
  {
      VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
@@ -733,87 +732,63 @@ static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, 
int queue_no,
      return 0;
  }

-static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)

+static int kvm_virtio_pci_vector_use_one(VirtIOPCIProxy *proxy, int queue_no)
  {
-    PCIDevice *dev = &proxy->pci_dev;
-    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
-    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
      unsigned int vector;
-    int ret, queue_no;
+    int ret;
      EventNotifier *n;
-    for (queue_no = 0; queue_no < nvqs; queue_no++) {
-        if (!virtio_queue_get_num(vdev, queue_no)) {
-            break;
-        }

So this check is not moved but deleted, is this intentional?

-        ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-        if (ret < 0) {
-            break;
-        }
-        if (vector >= msix_nr_vectors_allocated(dev)) {
-            continue;
-        }

So did this?

-        ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector);
-        if (ret < 0) {
-            goto undo;
-        }
-        /* If guest supports masking, set up irqfd now.
-         * Otherwise, delay until unmasked in the frontend.
-         */
-        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
-            ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
-            if (ret < 0) {
-                kvm_virtio_pci_vq_vector_release(proxy, vector);
-                goto undo;
-            }
-        }
+    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
+    if (ret < 0) {
+        return ret;
+    }
+    ret = kvm_virtio_pci_vq_vector_use(proxy, vector);
+    if (ret < 0) {
+        goto undo;
+    }
+    ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
+    if (ret < 0) {
+        goto undo;
      }
      return 0;
-
  undo:
-    while (--queue_no >= 0) {
-        vector = virtio_queue_vector(vdev, queue_no);
-        if (vector >= msix_nr_vectors_allocated(dev)) {
-            continue;
-        }
-        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
-            ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-            if (ret < 0) {
-                break;
-            }
-            kvm_virtio_pci_irqfd_release(proxy, n, vector);
-        }
-        kvm_virtio_pci_vq_vector_release(proxy, vector);
+    kvm_virtio_pci_irqfd_release(proxy, n, vector);
+    return ret;
+}
+static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
+{
+    int queue_no;
+    int ret = 0;
+    for (queue_no = 0; queue_no < nvqs; queue_no++) {
+        ret = kvm_virtio_pci_vector_use_one(proxy, queue_no);
      }
      return ret;
  }

-static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)

+
+static void kvm_virtio_pci_vector_release_one(VirtIOPCIProxy *proxy,
+                        int queue_no)
  {
-    PCIDevice *dev = &proxy->pci_dev;
      VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
      unsigned int vector;
-    int queue_no;
-    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
      EventNotifier *n;
-    int ret ;
+    int ret;
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
+    if (ret < 0) {
+        return;
+    }
+
+    if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
+        kvm_virtio_pci_irqfd_release(proxy, n, vector);
+    }
+    kvm_virtio_pci_vq_vector_release(proxy, vector);
+}
+static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
+{
+    int queue_no;
+
      for (queue_no = 0; queue_no < nvqs; queue_no++) {
-        if (!virtio_queue_get_num(vdev, queue_no)) {
-            break;
-        }

This is deleted by not removed.

-        ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-        if (ret < 0) {
-            break;
-        }
-        if (vector >= msix_nr_vectors_allocated(dev)) {
-            continue;
-        }

So did this.

Thanks

-        /* If guest supports masking, clean up irqfd now.
-         * Otherwise, it was cleaned when masked in the frontend.
-         */
-        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
-            kvm_virtio_pci_irqfd_release(proxy, n, vector);
-        }
-        kvm_virtio_pci_vq_vector_release(proxy, vector);
+        kvm_virtio_pci_vector_release_one(proxy, queue_no);
      }
  }