| Message ID | 197f962f6aab3d7fae77ad9f69a3d0dc1ffc07d7.1267122331.git.mst@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 02/25/2010 12:28 PM, Michael S. Tsirkin wrote: > 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 | 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 4c4d397..c1580e9 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-y += rwhandler.o > obj-$(CONFIG_KVM) += kvm.o kvm-all.o > obj-$(CONFIG_ISA_MMIO) += isa_mmio.o > 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<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; > Probably should handle EINTR, no? > +} > + > +int event_notifier_test(EventNotifier *e) > +{ > + uint64_t value; > + int r = read(e->fd,&value, sizeof value); > Coding Style is not quite explicit here but we always use 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 @@ > Needs copyright/license. Thanks for doing this abstraction, I'm really happy with it over direct eventfd usage. Regards, Anthony Liguori > +#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 805be1a..f12a8f5 100644 > --- a/qemu-common.h > +++ b/qemu-common.h > @@ -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; > >
On Thu, Feb 25, 2010 at 01:22:04PM -0600, Anthony Liguori wrote: > On 02/25/2010 12:28 PM, Michael S. Tsirkin wrote: >> 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 | 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 4c4d397..c1580e9 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-y += rwhandler.o >> obj-$(CONFIG_KVM) += kvm.o kvm-all.o >> obj-$(CONFIG_ISA_MMIO) += isa_mmio.o >> 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<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; >> > > Probably should handle EINTR, no? No, nonblocking eventfd read never returns EINTR. >> +} >> + >> +int event_notifier_test(EventNotifier *e) >> +{ >> + uint64_t value; >> + int r = read(e->fd,&value, sizeof value); >> > > Coding Style is not quite explicit here but we always use 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 @@ >> > > Needs copyright/license. > > Thanks for doing this abstraction, I'm really happy with it over direct > eventfd usage. > > Regards, > > Anthony Liguori > >> +#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 805be1a..f12a8f5 100644 >> --- a/qemu-common.h >> +++ b/qemu-common.h >> @@ -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; >> >> > >
diff --git a/Makefile.target b/Makefile.target index 4c4d397..c1580e9 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-y += rwhandler.o obj-$(CONFIG_KVM) += kvm.o kvm-all.o obj-$(CONFIG_ISA_MMIO) += isa_mmio.o 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 <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; +} 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 805be1a..f12a8f5 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -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 | 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