virtio-mmio: introduce set_host_notifier()

set_host_notifier() is introduced into virtio-mmio now. Most of codes came from virtio-pci.

---
 hw/virtio/virtio-mmio.c | 72
+++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

index 10123f3..6b40d56 100644
@@ -23,6 +23,7 @@
 #include "hw/virtio/virtio.h"
 #include "qemu/host-utils.h"
 #include "hw/virtio/virtio-bus.h"
+#include "qemu/error-report.h"
 
 /* #define DEBUG_VIRTIO_MMIO */
 

@@ -87,8 +88,59 @@ typedef struct {
     uint32_t guest_page_shift;
     /* virtio-bus */
     VirtioBusState bus;
+    bool ioeventfd_disabled;
+    bool ioeventfd_started;
 } VirtIOMMIOProxy;
 
+static int virtio_mmio_set_host_notifier_internal(VirtIOMMIOProxy *proxy,
+                                                  int n, bool assign,
+                                                  bool set_handler)
+{
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    VirtQueue *vq = virtio_get_queue(vdev, n);
+    EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
+    int r = 0;
+
+    if (assign) {
+        r = event_notifier_init(notifier, 1);
+        if (r < 0) {
+            error_report("%s: unable to init event notifier: %d",
+                         __func__, r);
+            return r;
+        }
+        virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
+        memory_region_add_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY,

4,
+ true, n, notifier);
+ } else {
+ memory_region_del_eventfd(&proxy->iomem, VIRTIO_MMIO_QUEUENOTIFY,
4,
+ true, n, notifier);
+ virtio_queue_set_host_notifier_fd_handler(vq, false, false);
+ event_notifier_cleanup(notifier);
+ }
+ return r;
+}
+
+static void virtio_mmio_stop_ioeventfd(VirtIOMMIOProxy *proxy) +{

+    int r;
+    int n;
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);

+
+ if (!proxy->ioeventfd_started) {
+ return;
+ }
+
+ for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
+ if (!virtio_queue_get_num(vdev, n)) {
+ continue;
+ }
+
+ r = virtio_mmio_set_host_notifier_internal(proxy, n, false, false);
+ assert(r >= 0);
+ }
+ proxy->ioeventfd_started = false;
+}
+
static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned
size)

 {
     VirtIOMMIOProxy *proxy = (VirtIOMMIOProxy *)opaque;
@@ -342,6 +394,25 @@ static void virtio_mmio_reset(DeviceState *d)
     proxy->guest_page_shift = 0;

}

+static int virtio_mmio_set_host_notifier(DeviceState *opaque, int n,
+ bool assign)
+{
+ VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
+
+ /* Stop using ioeventfd for virtqueue kick if the device starts using
host
+ * notifiers. This makes it easy to avoid stepping on each others'
toes.
+ */
+ proxy->ioeventfd_disabled = assign;
+ if (assign) {
+ virtio_mmio_stop_ioeventfd(proxy);
+ }
+ /* We don't need to start here: it's not needed because backend

+     * currently only stops on status change away from ok,
+     * reset, vmstop and such. If we do add code to start here,
+     * need to check vmstate, device state etc. */

+ return virtio_mmio_set_host_notifier_internal(proxy, n, assign, false);
+}
+
/* virtio-mmio device */

/* This is called by virtio-bus just after the device is plugged. */
@@ -399,6 +470,7 @@ static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data)

     k->notify = virtio_mmio_update_irq;
     k->save_config = virtio_mmio_save_config;
     k->load_config = virtio_mmio_load_config;
+    k->set_host_notifier = virtio_mmio_set_host_notifier;
     k->get_features = virtio_mmio_get_features;
     k->device_plugged = virtio_mmio_device_plugged;
     k->has_variable_vring_alignment = true;

1.9.5.msysgit.0


Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia

Meta-comment #1:

This is almost certainly not the correct email address of the original author :) I'd recommend to check another archive (e.g. marc.info) that does not mangle the email addresses in the patch body. The original author also should go into the author field in git.

Meta-comment #2:

Your patches are word-wrapped, which not only makes them harder to read but impossible to feed to git am.

(...)