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[Qemu-devel] [6396] I/O vector helpers (Avi Kivity)
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] [6396] I/O vector helpers (Avi Kivity) |
Date: |
Thu, 22 Jan 2009 16:59:21 +0000 |
Revision: 6396
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6396
Author: aliguori
Date: 2009-01-22 16:59:20 +0000 (Thu, 22 Jan 2009)
Log Message:
-----------
I/O vector helpers (Avi Kivity)
In general, it is not possible to predict the size of of an I/O vector since
a contiguous guest region may map to a disconiguous host region. Add some
helpers to manage I/O vector growth.
Signed-off-by: Avi Kivity <address@hidden>
Signed-off-by: Anthony Liguori <address@hidden>
Modified Paths:
--------------
trunk/cutils.c
trunk/qemu-common.h
Modified: trunk/cutils.c
===================================================================
--- trunk/cutils.c 2009-01-22 16:59:16 UTC (rev 6395)
+++ trunk/cutils.c 2009-01-22 16:59:20 UTC (rev 6396)
@@ -101,3 +101,50 @@
{
return 32 - clz32(i);
}
+
+/* io vectors */
+
+void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
+{
+ qiov->iov = qemu_malloc(alloc_hint * sizeof(struct iovec));
+ qiov->niov = 0;
+ qiov->nalloc = alloc_hint;
+}
+
+void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
+{
+ if (qiov->niov == qiov->nalloc) {
+ qiov->nalloc = 2 * qiov->nalloc + 1;
+ qiov->iov = qemu_realloc(qiov->iov, qiov->nalloc * sizeof(struct
iovec));
+ }
+ qiov->iov[qiov->niov].iov_base = base;
+ qiov->iov[qiov->niov].iov_len = len;
+ ++qiov->niov;
+}
+
+void qemu_iovec_destroy(QEMUIOVector *qiov)
+{
+ qemu_free(qiov->iov);
+}
+
+void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf)
+{
+ uint8_t *p = (uint8_t *)buf;
+ int i;
+
+ for (i = 0; i < qiov->niov; ++i) {
+ memcpy(p, qiov->iov[i].iov_base, qiov->iov[i].iov_len);
+ p += qiov->iov[i].iov_len;
+ }
+}
+
+void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf)
+{
+ const uint8_t *p = (const uint8_t *)buf;
+ int i;
+
+ for (i = 0; i < qiov->niov; ++i) {
+ memcpy(qiov->iov[i].iov_base, p, qiov->iov[i].iov_len);
+ p += qiov->iov[i].iov_len;
+ }
+}
Modified: trunk/qemu-common.h
===================================================================
--- trunk/qemu-common.h 2009-01-22 16:59:16 UTC (rev 6395)
+++ trunk/qemu-common.h 2009-01-22 16:59:20 UTC (rev 6396)
@@ -191,6 +191,18 @@
/* Force QEMU to stop what it's doing and service IO */
void qemu_service_io(void);
+typedef struct QEMUIOVector {
+ struct iovec *iov;
+ int niov;
+ int nalloc;
+} QEMUIOVector;
+
+void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
+void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
+void qemu_iovec_destroy(QEMUIOVector *qiov);
+void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf);
+void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf);
+
#endif /* dyngen-exec.h hack */
#endif
- [Qemu-devel] [6396] I/O vector helpers (Avi Kivity),
Anthony Liguori <=