[PATCH 6/8] kvm tools: steal iovec handling routines from the kernel

From: Sasha Levin <sasha.levin@oracle.com>
To: penberg@kernel.org, asias@redhat.com
Cc: kvm@vger.kernel.org, Sasha Levin <sasha.levin@oracle.com>
Subject: [PATCH 6/8] kvm tools: steal iovec handling routines from the kernel
Date: Fri,  3 May 2013 16:29:15 -0400	[thread overview]
Message-ID: <1367612957-6719-6-git-send-email-sasha.levin@oracle.com> (raw)
In-Reply-To: <1367612957-6719-1-git-send-email-sasha.levin@oracle.com>

They're hidden inside net/core/iovec.c. It'd be nice to just link to that
but they're not too generic and come with tons of net/ specific code we
don't want. So we just copy over the relevant parts.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
 tools/kvm/Makefile               |   1 +
 tools/kvm/include/kvm/iovec.h    |  21 +++++++
 tools/kvm/include/linux/kernel.h |  10 ++++
 tools/kvm/util/iovec.c           | 126 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 158 insertions(+)
 create mode 100644 tools/kvm/include/kvm/iovec.h
 create mode 100644 tools/kvm/util/iovec.c

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index a0a0a9b..70accaa 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -86,6 +86,7 @@ OBJS	+= net/uip/csum.o
 OBJS	+= net/uip/dhcp.o
 OBJS	+= kvm-cmd.o
 OBJS	+= util/init.o
+OBJS    += util/iovec.o
 OBJS	+= util/rbtree.o
 OBJS	+= util/threadpool.o
 OBJS	+= util/parse-options.o
diff --git a/tools/kvm/include/kvm/iovec.h b/tools/kvm/include/kvm/iovec.h
new file mode 100644
index 0000000..fe79dd4
--- /dev/null
+++ b/tools/kvm/include/kvm/iovec.h
@@ -0,0 +1,21 @@
+#ifndef KVM_UTIL_IOVEC_H_
+#define KVM_UTIL_IOVEC_H_
+
+extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
+extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
+				size_t offset, int len);
+extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int len);
+extern int memcpy_toiovecend(const struct iovec *v, unsigned char *kdata,
+				size_t offset, int len);
+
+static inline size_t iov_size(const struct iovec *iovec, size_t len)
+{
+	size_t size = 0, i;
+
+	for (i = 0; i < len; i++)
+		size += iovec[i].iov_len;
+
+	return size;
+}
+
+#endif
diff --git a/tools/kvm/include/linux/kernel.h b/tools/kvm/include/linux/kernel.h
index 1e9abe9..f2bff5f 100644
--- a/tools/kvm/include/linux/kernel.h
+++ b/tools/kvm/include/linux/kernel.h
@@ -36,6 +36,16 @@
 	(void) (&_max1 == &_max2);		\
 	_max1 > _max2 ? _max1 : _max2; })
 
+#define min_t(type, x, y) ({                    \
+	type __min1 = (x);                      \
+	type __min2 = (y);                      \
+	__min1 < __min2 ? __min1: __min2; })
+
+#define max_t(type, x, y) ({                    \
+	type __max1 = (x);                      \
+	type __max2 = (y);                      \
+	__max1 > __max2 ? __max1: __max2; })
+
 #define true 1
 
 #endif
diff --git a/tools/kvm/util/iovec.c b/tools/kvm/util/iovec.c
new file mode 100644
index 0000000..0c8b9cf
--- /dev/null
+++ b/tools/kvm/util/iovec.c
@@ -0,0 +1,126 @@
+/*
+ *	iovec manipulation routines.
+ *
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ *	Fixes:
+ *		Andrew Lunn	:	Errors in iovec copying.
+ *		Pedro Roque	:	Added memcpy_fromiovecend and
+ *					csum_..._fromiovecend.
+ *		Andi Kleen	:	fixed error handling for 2.1
+ *		Alexey Kuznetsov:	2.1 optimisations
+ *		Andi Kleen	:	Fix csum*fromiovecend for IPv6.
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <sys/uio.h>
+#include <kvm/iovec.h>
+#include <string.h>
+
+/*
+ *	Copy kernel to iovec. Returns -EFAULT on error.
+ *
+ *	Note: this modifies the original iovec.
+ */
+
+int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
+{
+	while (len > 0) {
+		if (iov->iov_len) {
+			int copy = min_t(unsigned int, iov->iov_len, len);
+			memcpy(iov->iov_base, kdata, copy);
+			kdata += copy;
+			len -= copy;
+			iov->iov_len -= copy;
+			iov->iov_base += copy;
+		}
+		iov++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_toiovec);
+
+/*
+ *	Copy kernel to iovec. Returns -EFAULT on error.
+ */
+
+int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
+		      size_t offset, int len)
+{
+	int copy;
+	for (; len > 0; ++iov) {
+		/* Skip over the finished iovecs */
+		if (unlikely(offset >= iov->iov_len)) {
+			offset -= iov->iov_len;
+			continue;
+		}
+		copy = min_t(unsigned int, iov->iov_len - offset, len);
+		memcpy(iov->iov_base + offset, kdata, copy);
+		offset = 0;
+		kdata += copy;
+		len -= copy;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_toiovecend);
+
+/*
+ *	Copy iovec to kernel. Returns -EFAULT on error.
+ *
+ *	Note: this modifies the original iovec.
+ */
+
+int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
+{
+	while (len > 0) {
+		if (iov->iov_len) {
+			int copy = min_t(unsigned int, len, iov->iov_len);
+			memcpy(kdata, iov->iov_base, copy);
+			len -= copy;
+			kdata += copy;
+			iov->iov_base += copy;
+			iov->iov_len -= copy;
+		}
+		iov++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_fromiovec);
+
+/*
+ *	Copy iovec from kernel. Returns -EFAULT on error.
+ */
+
+int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
+			size_t offset, int len)
+{
+	/* Skip over the finished iovecs */
+	while (offset >= iov->iov_len) {
+		offset -= iov->iov_len;
+		iov++;
+	}
+
+	while (len > 0) {
+		char *base = iov->iov_base + offset;
+		int copy = min_t(unsigned int, len, iov->iov_len - offset);
+
+		offset = 0;
+		memcpy(kdata, base, copy);
+		len -= copy;
+		kdata += copy;
+		iov++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_fromiovecend);
-- 
1.8.2.1

