This patch adds compatibility code so that we can make use of eventfd() within
QEMU. eventfd() is a pretty useful mechanism as it allows multiple
notifications to be batched in a single system call.
We emulate eventfd() using a standard pipe().
Signed-off-by: Anthony Liguori <[EMAIL PROTECTED]>
diff --git a/qemu/Makefile.target b/qemu/Makefile.target
index bb4b9a3..46654f3 100644
--- a/qemu/Makefile.target
+++ b/qemu/Makefile.target
@@ -208,7 +208,7 @@ CPPFLAGS+=-I$(SRC_PATH)/tcg/sparc
endif
ifeq ($(USE_KVM), 1)
-LIBOBJS+=qemu-kvm.o
+LIBOBJS+=qemu-kvm.o kvm-compatfd.o
endif
ifdef CONFIG_SOFTFLOAT
LIBOBJS+=fpu/softfloat.o
diff --git a/qemu/kvm-compatfd.c b/qemu/kvm-compatfd.c
new file mode 100644
index 0000000..1b030ba
--- /dev/null
+++ b/qemu/kvm-compatfd.c
@@ -0,0 +1,33 @@
+/*
+ * signalfd/eventfd compatibility
+ *
+ * Copyright IBM, Corp. 2008
+ *
+ * Authors:
+ * Anthony Liguori <[EMAIL PROTECTED]>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "qemu-kvm.h"
+
+#include <sys/syscall.h>
+
+int kvm_eventfd(int *fds)
+{
+#if defined(SYS_eventfd)
+ int ret;
+
+ ret = syscall(SYS_eventfd, 0);
+ if (ret >= 0) {
+ fds[0] = fds[1] = ret;
+ return 0;
+ } else if (!(ret == -1 && errno == ENOSYS))
+ return ret;
+#endif
+
+ return pipe(fds);
+}
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
index 024a653..8fa3c1b 100644
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -79,6 +79,8 @@ int handle_powerpc_dcr_read(int vcpu, uint32_t dcrn, uint32_t
*data);
int handle_powerpc_dcr_write(int vcpu,uint32_t dcrn, uint32_t data);
#endif
+int kvm_eventfd(int *fds);
+
#define ALIGN(x, y) (((x)+(y)-1) & ~((y)-1))
#define BITMAP_SIZE(m) (ALIGN(((m)>>TARGET_PAGE_BITS), HOST_LONG_BITS) / 8)
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