From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Nd17r-0003ec-80 for qemu-devel@nongnu.org; Thu, 04 Feb 2010 07:48:03 -0500 Received: from [199.232.76.173] (port=55433 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Nd17q-0003eT-VV for qemu-devel@nongnu.org; Thu, 04 Feb 2010 07:48:03 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1Nd17p-0007n6-07 for qemu-devel@nongnu.org; Thu, 04 Feb 2010 07:48:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56034) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1Nd17o-0007mp-IG for qemu-devel@nongnu.org; Thu, 04 Feb 2010 07:48:00 -0500 Date: Thu, 4 Feb 2010 14:44:48 +0200 From: "Michael S. Tsirkin" Message-ID: <20100204124448.GF22559@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: [Qemu-devel] [PATCH 05/15] notifier: event notifier implementation List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori , qemu-devel@nongnu.org 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 --- Makefile.target | 1 + hw/notifier.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ hw/notifier.h | 16 ++++++++++++++++ qemu-common.h | 1 + 4 files changed, 68 insertions(+), 0 deletions(-) create mode 100644 hw/notifier.c create mode 100644 hw/notifier.h diff --git a/Makefile.target b/Makefile.target index 5c0ef1f..31bde66 100644 --- a/Makefile.target +++ b/Makefile.target @@ -173,6 +173,7 @@ 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-$(CONFIG_KVM) += kvm.o kvm-all.o obj-$(CONFIG_ISA_MMIO) += isa_mmio.o LIBS+=-lz diff --git a/hw/notifier.c b/hw/notifier.c new file mode 100644 index 0000000..dff38de --- /dev/null +++ b/hw/notifier.c @@ -0,0 +1,50 @@ +#include "hw.h" +#include "notifier.h" +#ifdef CONFIG_EVENTFD +#include +#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; +} diff --git a/hw/notifier.h b/hw/notifier.h new file mode 100644 index 0000000..24117ea --- /dev/null +++ b/hw/notifier.h @@ -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 diff --git a/qemu-common.h b/qemu-common.h index b09f717..423e962 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -224,6 +224,7 @@ typedef struct uWireSlave uWireSlave; typedef struct I2SCodec I2SCodec; typedef struct DeviceState DeviceState; typedef struct SSIBus SSIBus; +typedef struct EventNotifier EventNotifier; /* CPU save/load. */ void cpu_save(QEMUFile *f, void *opaque); -- 1.6.6.144.g5c3af