@@ -172,6 +172,7 @@ obj-y = vl.o async.o monitor.o pci.o pci_host.o pcie_host.o machine.o gdbstub.o
# virtio has to be here due to weird dependency between PCI and virtio-net.
# need to fix this properly
obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-pci.o virtio-serial-bus.o
+obj-y += notifier.o
obj-y += rwhandler.o
obj-$(CONFIG_KVM) += kvm.o kvm-all.o
obj-$(CONFIG_ISA_MMIO) += isa_mmio.o
new file mode 100644
@@ -0,0 +1,62 @@
+/*
+ * event notifier support
+ *
+ * Copyright Red Hat, Inc. 2010
+ *
+ * Authors:
+ * Michael S. Tsirkin <mst@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "hw.h"
+#include "notifier.h"
+#ifdef CONFIG_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
+int event_notifier_init(EventNotifier *e, int active)
+{
+#ifdef CONFIG_EVENTFD
+ int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+ e->fd = fd;
+ return 0;
+#else
+ return -ENOSYS;
+#endif
+}
+
+void event_notifier_cleanup(EventNotifier *e)
+{
+ close(e->fd);
+}
+
+int event_notifier_get_fd(EventNotifier *e)
+{
+ return e->fd;
+}
+
+int event_notifier_test_and_clear(EventNotifier *e)
+{
+ uint64_t value;
+ int r = read(e->fd, &value, sizeof(value));
+ return r == sizeof(value);
+}
+
+int event_notifier_test(EventNotifier *e)
+{
+ uint64_t value;
+ int r = read(e->fd, &value, sizeof(value));
+ if (r == sizeof(value)) {
+ /* restore previous value. */
+ int s = write(e->fd, &value, sizeof(value));
+ /* never blocks because we use EFD_SEMAPHORE.
+ * If we didn't we'd get EAGAIN on overflow
+ * and we'd have to write code to ignore it. */
+ assert(s == sizeof(value));
+ }
+ return r == sizeof(value);
+}
new file mode 100644
@@ -0,0 +1,16 @@
+#ifndef QEMU_EVENT_NOTIFIER_H
+#define QEMU_EVENT_NOTIFIER_H
+
+#include "qemu-common.h"
+
+struct EventNotifier {
+ int fd;
+};
+
+int event_notifier_init(EventNotifier *, int active);
+void event_notifier_cleanup(EventNotifier *);
+int event_notifier_get_fd(EventNotifier *);
+int event_notifier_test_and_clear(EventNotifier *);
+int event_notifier_test(EventNotifier *);
+
+#endif
@@ -227,6 +227,7 @@ typedef struct uWireSlave uWireSlave;
typedef struct I2SCodec I2SCodec;
typedef struct DeviceState DeviceState;
typedef struct SSIBus SSIBus;
+typedef struct EventNotifier EventNotifier;
typedef uint64_t pcibus_t;
event notifiers are slightly generalized eventfd descriptors. Current implementation depends on eventfd because vhost is the only user, and vhost depends on eventfd anyway, but a stub is provided for non-eventfd case. We'll be able to further generalize this when another user comes along and we see how to best do this. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- Makefile.target | 1 + hw/notifier.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ hw/notifier.h | 16 ++++++++++++++ qemu-common.h | 1 + 4 files changed, 80 insertions(+), 0 deletions(-) create mode 100644 hw/notifier.c create mode 100644 hw/notifier.h