qemu/Revert-virtio-pci-decouple-the-single-vector-from-th.patch

From 074043d5d6c2610a320d2bc7d8649b7eff9c806e Mon Sep 17 00:00:00 2001
From: fangyi <eric.fangyi@huawei.com>
Date: Wed, 22 Nov 2023 10:01:17 +0800
Subject: [PATCH] Revert "virtio-pci: decouple the single vector from the
 interrupt process"

This reverts commit 316011b8a74e777eb3ba03171cd701a291c28867.

Fixes: 316011b8a7 ("virtio-pci: decouple the single vector from the interrupt process")
Cc: "Cindy Lu" <lulu@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: fangyi <eric.fangyi@huawei.com>
---
 hw/virtio/virtio-pci.c | 131 ++++++++++++++++++-----------------------
 1 file changed, 58 insertions(+), 73 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 75be770971..85d7357f66 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -762,6 +762,7 @@ 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];
@@ -824,103 +825,87 @@ static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, int queue_no,
     return 0;
 }
 
-static int kvm_virtio_pci_vector_use_one(VirtIOPCIProxy *proxy, int queue_no)
+static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
 {
-    unsigned int vector;
-    int ret;
-    EventNotifier *n;
     PCIDevice *dev = &proxy->pci_dev;
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
-
-    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-    if (ret < 0) {
-        return ret;
-    }
-    if (vector >= msix_nr_vectors_allocated(dev)) {
-        return 0;
-    }
-    ret = kvm_virtio_pci_vq_vector_use(proxy, 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);
+    unsigned int vector;
+    int ret, queue_no;
+    EventNotifier *n;
+    for (queue_no = 0; queue_no < nvqs; queue_no++) {
+        if (!virtio_queue_get_num(vdev, queue_no)) {
+            break;
+        }
+        ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
+        if (ret < 0) {
+            break;
+        }
+        if (vector >= msix_nr_vectors_allocated(dev)) {
+            continue;
+        }
+        ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector);
         if (ret < 0) {
-            kvm_virtio_pci_vq_vector_release(proxy, vector);
             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;
+            }
+        }
     }
-
     return 0;
-undo:
 
-    vector = virtio_queue_vector(vdev, queue_no);
-    if (vector >= msix_nr_vectors_allocated(dev)) {
-        return ret;
-    }
-    if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
-        ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-        if (ret < 0) {
-            return ret;
+undo:
+    while (--queue_no >= 0) {
+        vector = virtio_queue_vector(vdev, queue_no);
+        if (vector >= msix_nr_vectors_allocated(dev)) {
+            continue;
         }
-        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;
-    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
-
-    for (queue_no = 0; queue_no < nvqs; queue_no++) {
-        if (!virtio_queue_get_num(vdev, queue_no)) {
-            return -1;
+        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);
         }
-        ret = kvm_virtio_pci_vector_use_one(proxy, queue_no);
+        kvm_virtio_pci_vq_vector_release(proxy, vector);
     }
     return ret;
 }
 
-
-static void kvm_virtio_pci_vector_release_one(VirtIOPCIProxy *proxy,
-                                              int queue_no)
+static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
 {
+    PCIDevice *dev = &proxy->pci_dev;
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
     unsigned int vector;
-    EventNotifier *n;
-    int ret;
-    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
-    PCIDevice *dev = &proxy->pci_dev;
-
-    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
-    if (ret < 0) {
-        return;
-    }
-    if (vector >= msix_nr_vectors_allocated(dev)) {
-        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;
-    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
-
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    EventNotifier *n;
+    int ret ;
     for (queue_no = 0; queue_no < nvqs; queue_no++) {
         if (!virtio_queue_get_num(vdev, queue_no)) {
             break;
         }
-        kvm_virtio_pci_vector_release_one(proxy, queue_no);
+        ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
+        if (ret < 0) {
+            break;
+        }
+        if (vector >= msix_nr_vectors_allocated(dev)) {
+            continue;
+        }
+        /* 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);
     }
 }
 
-- 
2.27.0