gwj / at91sam9263 · Commits

Commit 44e3ee8a2aaee5df49cd440446fee4525144255f

Authored by aliguori
1 parent ba223c29

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 <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6396 c046a42c-6fe2-441c-8c8c-71466251a162
Inline Side-by-side
Showing 2 changed files with 59 additions and 0 deletions
cutils.c
  View file @44e3ee8
... ... @@ -101,3 +101,50 @@ int qemu_fls(int i)
101 101 {
102 102 return 32 - clz32(i);
103 103 }
  104 +
  105 +/* io vectors */
  106 +
  107 +void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
  108 +{
  109 + qiov->iov = qemu_malloc(alloc_hint * sizeof(struct iovec));
  110 + qiov->niov = 0;
  111 + qiov->nalloc = alloc_hint;
  112 +}
  113 +
  114 +void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
  115 +{
  116 + if (qiov->niov == qiov->nalloc) {
  117 + qiov->nalloc = 2 * qiov->nalloc + 1;
  118 + qiov->iov = qemu_realloc(qiov->iov, qiov->nalloc * sizeof(struct iovec));
  119 + }
  120 + qiov->iov[qiov->niov].iov_base = base;
  121 + qiov->iov[qiov->niov].iov_len = len;
  122 + ++qiov->niov;
  123 +}
  124 +
  125 +void qemu_iovec_destroy(QEMUIOVector *qiov)
  126 +{
  127 + qemu_free(qiov->iov);
  128 +}
  129 +
  130 +void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf)
  131 +{
  132 + uint8_t *p = (uint8_t *)buf;
  133 + int i;
  134 +
  135 + for (i = 0; i < qiov->niov; ++i) {
  136 + memcpy(p, qiov->iov[i].iov_base, qiov->iov[i].iov_len);
  137 + p += qiov->iov[i].iov_len;
  138 + }
  139 +}
  140 +
  141 +void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf)
  142 +{
  143 + const uint8_t *p = (const uint8_t *)buf;
  144 + int i;
  145 +
  146 + for (i = 0; i < qiov->niov; ++i) {
  147 + memcpy(qiov->iov[i].iov_base, p, qiov->iov[i].iov_len);
  148 + p += qiov->iov[i].iov_len;
  149 + }
  150 +}
... ...
qemu-common.h
  View file @44e3ee8
... ... @@ -191,6 +191,18 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id);
191 191 /* Force QEMU to stop what it's doing and service IO */
192 192 void qemu_service_io(void);
193 193  
  194 +typedef struct QEMUIOVector {
  195 + struct iovec *iov;
  196 + int niov;
  197 + int nalloc;
  198 +} QEMUIOVector;
  199 +
  200 +void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
  201 +void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
  202 +void qemu_iovec_destroy(QEMUIOVector *qiov);
  203 +void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf);
  204 +void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf);
  205 +
194 206 #endif /* dyngen-exec.h hack */
195 207  
196 208 #endif
... ...