[PATCH v3 09/10] kvm tools: Add aio read write functions

[Sasha Levin <levinsasha928@xxxxxxxxx>]

This patch adds basic native vectored AIO functions.

These functions should be optimized to process multiple io
requests at once.

Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
---
 tools/kvm/Makefile                 |    7 +++++++
 tools/kvm/config/feature-tests.mak |   10 ++++++++++
 tools/kvm/include/kvm/read-write.h |   11 +++++++++++
 tools/kvm/read-write.c             |   26 ++++++++++++++++++++++++++
 4 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index d9baa69..d4598ca 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -115,6 +115,13 @@ ifeq ($(has_ZLIB),y)
 	LIBS	+= -lz
 endif
 
+FLAGS_AIO := $(CFLAGS) -laio
+has_AIO := $(call try-cc,$(SOURCE_AIO),$(FLAGS_AIO))
+ifeq ($(has_AIO),y)
+	CFLAGS	+= -DCONFIG_HAS_AIO
+	LIBS	+= -laio
+endif
+
 DEPS	:= $(patsubst %.o,%.d,$(OBJS))
 
 # Exclude BIOS object files from header dependencies.
diff --git a/tools/kvm/config/feature-tests.mak b/tools/kvm/config/feature-tests.mak
index a75c31d..be9ebc0 100644
--- a/tools/kvm/config/feature-tests.mak
+++ b/tools/kvm/config/feature-tests.mak
@@ -156,3 +156,13 @@ int main(void)
 	return 0;
 }
 endef
+
+define SOURCE_AIO
+#include <libaio.h>
+
+int main(void)
+{
+	io_setup(0, NULL);
+	return 0;
+}
+endef
diff --git a/tools/kvm/include/kvm/read-write.h b/tools/kvm/include/kvm/read-write.h
index 3351103..67571f9 100644
--- a/tools/kvm/include/kvm/read-write.h
+++ b/tools/kvm/include/kvm/read-write.h
@@ -5,6 +5,10 @@
 #include <sys/uio.h>
 #include <unistd.h>
 
+#ifdef CONFIG_HAS_AIO
+#include <libaio.h>
+#endif
+
 ssize_t xread(int fd, void *buf, size_t count);
 ssize_t xwrite(int fd, const void *buf, size_t count);
 
@@ -29,4 +33,11 @@ ssize_t xpwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset);
 ssize_t preadv_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset);
 ssize_t pwritev_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offset);
 
+#ifdef CONFIG_HAS_AIO
+int aio_preadv(io_context_t ctx, struct iocb *iocb, int fd, const struct iovec *iov, int iovcnt,
+		off_t offset, int ev, void *param);
+int aio_pwritev(io_context_t ctx, struct iocb *iocb, int fd, const struct iovec *iov, int iovcnt,
+		off_t offset, int ev, void *param);
+#endif
+
 #endif /* KVM_READ_WRITE_H */
diff --git a/tools/kvm/read-write.c b/tools/kvm/read-write.c
index 737fb26..55473ba 100644
--- a/tools/kvm/read-write.c
+++ b/tools/kvm/read-write.c
@@ -316,3 +316,29 @@ ssize_t pwritev_in_full(int fd, const struct iovec *iov, int iovcnt, off_t offse
 
 	return total;
 }
+
+#ifdef CONFIG_HAS_AIO
+int aio_pwritev(io_context_t ctx, struct iocb *iocb, int fd, const struct iovec *iov, int iovcnt,
+		off_t offset, int ev, void *param)
+{
+	struct iocb *ios[1] = { iocb };
+
+	io_prep_pwritev(iocb, fd, iov, iovcnt, offset);
+	io_set_eventfd(iocb, ev);
+	iocb->data = param;
+
+	return io_submit(ctx, 1, ios);
+}
+
+int aio_preadv(io_context_t ctx, struct iocb *iocb, int fd, const struct iovec *iov, int iovcnt,
+		off_t offset, int ev, void *param)
+{
+	struct iocb *ios[1] = { iocb };
+
+	io_prep_preadv(iocb, fd, iov, iovcnt, offset);
+	io_set_eventfd(iocb, ev);
+	iocb->data = param;
+
+	return io_submit(ctx, 1, ios);
+}
+#endif
\ No newline at end of file
-- 
1.7.7.1

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