Hello Cindy,

On 1/8/22 02:04, Michael S. Tsirkin wrote:
From: Cindy Lu <l...@redhat.com>

Add support for configure interrupt, The process is used kvm_irqfd_assign
to set the gsi to kernel. When the configure notifier was signal by
host, qemu will inject a msix interrupt to guest

Signed-off-by: Cindy Lu <l...@redhat.com>
Message-Id: <20211104164827.21911-11-l...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
  hw/virtio/virtio-pci.h |  4 +-
  hw/virtio/virtio-pci.c | 92 ++++++++++++++++++++++++++++++++++++------
  2 files changed, 83 insertions(+), 13 deletions(-)

diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index 2446dcd9ae..b704acc5a8 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -251,5 +251,7 @@ void virtio_pci_types_register(const 
VirtioPCIDeviceTypeInfo *t);
   * @fixed_queues.
   */
  unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
-
+void virtio_pci_set_guest_notifier_fd_handler(VirtIODevice *vdev, VirtQueue 
*vq,
+                                              int n, bool assign,
+                                              bool with_irqfd);
  #endif
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 7201cf3dc1..98fb5493ae 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -727,7 +727,8 @@ static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, 
int queue_no,
      VirtQueue *vq;
if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
-        return -1;
+        *n = virtio_config_get_guest_notifier(vdev);
+        *vector = vdev->config_vector;
      } else {
          if (!virtio_queue_get_num(vdev, queue_no)) {
              return -1;
@@ -802,6 +803,10 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy 
*proxy, int nvqs)
      return ret;
  }
+static int kvm_virtio_pci_vector_config_use(VirtIOPCIProxy *proxy)
+{
+    return kvm_virtio_pci_vector_use_one(proxy, VIRTIO_CONFIG_IRQ_IDX);
+}
static void kvm_virtio_pci_vector_release_one(VirtIOPCIProxy *proxy,
                                                int queue_no)
@@ -839,6 +844,11 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy 
*proxy, int nvqs)
      }
  }
+static void kvm_virtio_pci_vector_config_release(VirtIOPCIProxy *proxy)
+{
+    kvm_virtio_pci_vector_release_one(proxy, VIRTIO_CONFIG_IRQ_IDX);
+}
+
  static int virtio_pci_one_vector_unmask(VirtIOPCIProxy *proxy,
                                         unsigned int queue_no,
                                         unsigned int vector,
@@ -920,9 +930,17 @@ static int virtio_pci_vector_unmask(PCIDevice *dev, 
unsigned vector,
          }
          vq = virtio_vector_next_queue(vq);
      }
-
+    /* unmask config intr */
+    n = virtio_config_get_guest_notifier(vdev);
+    ret = virtio_pci_one_vector_unmask(proxy, VIRTIO_CONFIG_IRQ_IDX, vector,
+                                       msg, n);
+    if (ret < 0) {
+        goto undo_config;
+    }
      return 0;
-
+undo_config:
+    n = virtio_config_get_guest_notifier(vdev);
+    virtio_pci_one_vector_mask(proxy, VIRTIO_CONFIG_IRQ_IDX, vector, n);
  undo:
      vq = virtio_vector_first_queue(vdev, vector);
      while (vq && unmasked >= 0) {
@@ -956,6 +974,8 @@ static void virtio_pci_vector_mask(PCIDevice *dev, unsigned 
vector)
          }
          vq = virtio_vector_next_queue(vq);
      }
+    n = virtio_config_get_guest_notifier(vdev);
+    virtio_pci_one_vector_mask(proxy, VIRTIO_CONFIG_IRQ_IDX, vector, n);
  }
static void virtio_pci_vector_poll(PCIDevice *dev,
@@ -987,6 +1007,34 @@ static void virtio_pci_vector_poll(PCIDevice *dev,
              msix_set_pending(dev, vector);
          }
      }
+    /* poll the config intr */
+    ret = virtio_pci_get_notifier(proxy, VIRTIO_CONFIG_IRQ_IDX, &notifier,
+                                  &vector);
+    if (ret < 0) {
+        return;
+    }
+    if (vector < vector_start || vector >= vector_end ||
+        !msix_is_masked(dev, vector)) {
+        return;
+    }
+    if (k->guest_notifier_pending) {
+        if (k->guest_notifier_pending(vdev, VIRTIO_CONFIG_IRQ_IDX)) {
+            msix_set_pending(dev, vector);
+        }
+    } else if (event_notifier_test_and_clear(notifier)) {
+        msix_set_pending(dev, vector);
+    }
+}
+
+void virtio_pci_set_guest_notifier_fd_handler(VirtIODevice *vdev, VirtQueue 
*vq,
+                                              int n, bool assign,
+                                              bool with_irqfd)
+{
+    if (n == VIRTIO_CONFIG_IRQ_IDX) {
+        virtio_config_set_guest_notifier_fd_handler(vdev, assign, with_irqfd);
+    } else {
+        virtio_queue_set_guest_notifier_fd_handler(vq, assign, with_irqfd);
+    }
  }
static int virtio_pci_set_guest_notifier(DeviceState *d, int n, bool assign,
@@ -995,17 +1043,25 @@ static int virtio_pci_set_guest_notifier(DeviceState *d, 
int n, bool assign,
      VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
      VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
      VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
-    VirtQueue *vq = virtio_get_queue(vdev, n);
-    EventNotifier *notifier = virtio_queue_get_guest_notifier(vq);
+    VirtQueue *vq = NULL;
+    EventNotifier *notifier = NULL;
+
+    if (n == VIRTIO_CONFIG_IRQ_IDX) {
+        notifier = virtio_config_get_guest_notifier(vdev);
+    } else {
+        vq = virtio_get_queue(vdev, n);
+        notifier = virtio_queue_get_guest_notifier(vq);
+    }
if (assign) {
          int r = event_notifier_init(notifier, 0);
          if (r < 0) {
              return r;
          }
-        virtio_queue_set_guest_notifier_fd_handler(vq, true, with_irqfd);
+        virtio_pci_set_guest_notifier_fd_handler(vdev, vq, n, true, 
with_irqfd);
      } else {
-        virtio_queue_set_guest_notifier_fd_handler(vq, false, with_irqfd);
+        virtio_pci_set_guest_notifier_fd_handler(vdev, vq, n, false,
+                                                 with_irqfd);
          event_notifier_cleanup(notifier);
      }
@@ -1047,6 +1103,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
          msix_unset_vector_notifiers(&proxy->pci_dev);
          if (proxy->vector_irqfd) {
              kvm_virtio_pci_vector_release(proxy, nvqs);
+            kvm_virtio_pci_vector_config_release(proxy);
              g_free(proxy->vector_irqfd);
              proxy->vector_irqfd = NULL;
          }
@@ -1062,7 +1119,11 @@ static int virtio_pci_set_guest_notifiers(DeviceState 
*d, int nvqs, bool assign)
              goto assign_error;
          }
      }
-
+    r = virtio_pci_set_guest_notifier(d, VIRTIO_CONFIG_IRQ_IDX, assign,
+                                      with_irqfd);
+    if (r < 0) {
+        goto config_assign_error;
+    }
      /* Must set vector notifier after guest notifier has been assigned */
      if ((with_irqfd || k->guest_notifier_mask) && assign) {
          if (with_irqfd) {
@@ -1071,11 +1132,14 @@ static int virtio_pci_set_guest_notifiers(DeviceState 
*d, int nvqs, bool assign)
                            msix_nr_vectors_allocated(&proxy->pci_dev));
              r = kvm_virtio_pci_vector_use(proxy, nvqs);
              if (r < 0) {
-                goto assign_error;
+                goto config_assign_error;
              }
          }
-        r = msix_set_vector_notifiers(&proxy->pci_dev,
-                                      virtio_pci_vector_unmask,
+        r = kvm_virtio_pci_vector_config_use(proxy);
+        if (r < 0) {
+            goto config_error;
+        }


This is crashing a QEMU TCG machine using vhost (no irqfd). Below is a fix
but I doubt it is complete.

Thanks,

C.


From dde4d7b21c851a33d2d03bddd18464ae4e777a3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <c...@kaod.org>
Date: Sun, 9 Jan 2022 10:40:47 +0100
Subject: [PATCH] vhost: Fix support for configure interrupt
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

irqfd is not necessarily  in use (TCG using vhost).

Cc: Cindy Lu <l...@redhat.com>
Fixes: d5d24d859c39 ("virtio-pci: add support for configure interrupt")
Signed-off-by: Cédric Le Goater <c...@kaod.org>
---
 hw/virtio/virtio-pci.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 98fb5493ae06..39ebb042860d 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1134,10 +1134,12 @@ static int virtio_pci_set_guest_notifiers(DeviceState 
*d, int nvqs, bool assign)
             if (r < 0) {
                 goto config_assign_error;
             }
-        }
-        r = kvm_virtio_pci_vector_config_use(proxy);
-        if (r < 0) {
-            goto config_error;
+
+            r = kvm_virtio_pci_vector_config_use(proxy);
+            if (r < 0) {
+                abort();
+                goto config_error;
+            }
         }
         r = msix_set_vector_notifiers(&proxy->pci_dev, 
virtio_pci_vector_unmask,
                                       virtio_pci_vector_mask,
--
2.31.1


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