qemu-kvm/kvm-virtio-pci-decouple-the-single-vector-from-the-inter.patch

From 58cd577ff157cfaf7506bba135db58e75c330ff0 Mon Sep 17 00:00:00 2001
From: Cindy Lu <lulu@redhat.com>
Date: Thu, 22 Dec 2022 15:04:44 +0800
Subject: [PATCH 03/31] virtio-pci: decouple the single vector from the
 interrupt process
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RH-Author: Cindy Lu <lulu@redhat.com>
RH-MergeRequest: 132: vhost-vdpa: support config interrupt in vhost-vdpa
RH-Bugzilla: 1905805
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Eugenio Pérez <eperezma@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [3/10] 2c79cb678f005fb2f53b2db0f237347634ab3422 (lulu6/qemu-kvm3)

https://bugzilla.redhat.com/show_bug.cgi?id=1905805

To reuse the interrupt process in configure interrupt
Need to decouple the single vector from the interrupt process.
We add new function kvm_virtio_pci_vector_use_one and _release_one.
These functions are used for the single vector, the whole process will
finish in the loop with vq number.

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20221222070451.936503-4-lulu@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit ee3b8dc6cc496ba7f4e27aed4493275c706a7942)
Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 hw/virtio/virtio-pci.c | 131 +++++++++++++++++++++++------------------
 1 file changed, 73 insertions(+), 58 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 52c7692fff..ec816ea367 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -699,7 +699,6 @@ 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];
@@ -764,87 +763,103 @@ 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)
 {
+    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);
-    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);
+
+    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);
         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;
 
+    return 0;
 undo:
-    while (--queue_no >= 0) {
-        vector = virtio_queue_vector(vdev, queue_no);
-        if (vector >= msix_nr_vectors_allocated(dev)) {
-            continue;
+
+    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;
         }
-        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_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;
         }
-        kvm_virtio_pci_vq_vector_release(proxy, vector);
+        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);
+    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);
+
     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;
-        }
-        /* 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);
     }
 }
 
-- 
2.31.1