kvm: require KVM_CAP_IOEVENTFD and KVM_CAP_IOEVENTFD_ANY_LENGTH

KVM_CAP_IOEVENTFD_ANY_LENGTH was added in Linux 4.4, released in 2016.
Assume that it is present.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 5 insertions, 25 deletions

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index b8a7b55..7b42ae8 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -264,11 +264,6 @@ struct scrub_regions {
     int fd_idx;
 };
 
-static bool ioeventfd_enabled(void)
-{
-    return !kvm_enabled() || kvm_eventfds_enabled();
-}
-
 static int vhost_user_read_header(struct vhost_dev *dev, VhostUserMsg *msg)
 {
     struct vhost_user *u = dev->opaque;
@@ -1318,7 +1313,7 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
         .hdr.size = sizeof(msg.payload.u64),
     };
 
-    if (ioeventfd_enabled() && file->fd > 0) {
+    if (file->fd > 0) {
         fds[fd_num++] = file->fd;
     } else {
         msg.payload.u64 |= VHOST_USER_VRING_NOFD_MASK;
diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
index c2c6d85..22f15e1 100644
--- a/hw/virtio/virtio-mmio.c
+++ b/hw/virtio/virtio-mmio.c
@@ -761,10 +761,6 @@ static void virtio_mmio_realizefn(DeviceState *d, Error **errp)
     qbus_init(&proxy->bus, sizeof(proxy->bus), TYPE_VIRTIO_MMIO_BUS, d, NULL);
     sysbus_init_irq(sbd, &proxy->irq);
 
-    if (!kvm_eventfds_enabled()) {
-        proxy->flags &= ~VIRTIO_IOMMIO_FLAG_USE_IOEVENTFD;
-    }
-
     /* fd-based ioevents can't be synchronized in record/replay */
     if (replay_mode != REPLAY_MODE_NONE) {
         proxy->flags &= ~VIRTIO_IOMMIO_FLAG_USE_IOEVENTFD;
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 5f61433..205dbf2 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -332,7 +332,6 @@ static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
     VirtQueue *vq = virtio_get_queue(vdev, n);
     bool legacy = virtio_pci_legacy(proxy);
     bool modern = virtio_pci_modern(proxy);
-    bool fast_mmio = kvm_ioeventfd_any_length_enabled();
     bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;
     MemoryRegion *modern_mr = &proxy->notify.mr;
     MemoryRegion *modern_notify_mr = &proxy->notify_pio.mr;
@@ -343,13 +342,8 @@ static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
 
     if (assign) {
         if (modern) {
-            if (fast_mmio) {
-                memory_region_add_eventfd(modern_mr, modern_addr, 0,
-                                          false, n, notifier);
-            } else {
-                memory_region_add_eventfd(modern_mr, modern_addr, 2,
-                                          false, n, notifier);
-            }
+            memory_region_add_eventfd(modern_mr, modern_addr, 0,
+                                      false, n, notifier);
             if (modern_pio) {
                 memory_region_add_eventfd(modern_notify_mr, 0, 2,
                                               true, n, notifier);
@@ -361,13 +355,8 @@ static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
         }
     } else {
         if (modern) {
-            if (fast_mmio) {
-                memory_region_del_eventfd(modern_mr, modern_addr, 0,
-                                          false, n, notifier);
-            } else {
-                memory_region_del_eventfd(modern_mr, modern_addr, 2,
-                                          false, n, notifier);
-            }
+            memory_region_del_eventfd(modern_mr, modern_addr, 0,
+                                      false, n, notifier);
             if (modern_pio) {
                 memory_region_del_eventfd(modern_notify_mr, 0, 2,
                                           true, n, notifier);