Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
lguest: wrap last_avail accesses.
To simplify the transition to when we publish indices in the ring
(and make shuffling my patch queue easier), wrap them in a lg_last_avail()
macro.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
+11
-5
Documentation/lguest/lguest.c
+11
-5
Documentation/lguest/lguest.c
···
191
return iov->iov_base;
192
}
193
194
/* The virtio configuration space is defined to be little-endian. x86 is
195
* little-endian too, but it's nice to be explicit so we have these helpers. */
196
#define cpu_to_le16(v16) (v16)
···
693
unsigned int *out_num, unsigned int *in_num)
694
{
695
unsigned int i, head;
696
697
/* Check it isn't doing very strange things with descriptor numbers. */
698
-
if ((u16)(vq->vring.avail->idx - vq->last_avail_idx) > vq->vring.num)
699
errx(1, "Guest moved used index from %u to %u",
700
-
vq->last_avail_idx, vq->vring.avail->idx);
701
702
/* If there's nothing new since last we looked, return invalid. */
703
-
if (vq->vring.avail->idx == vq->last_avail_idx)
704
return vq->vring.num;
705
706
/* Grab the next descriptor number they're advertising, and increment
707
* the index we've seen. */
708
-
head = vq->vring.avail->ring[vq->last_avail_idx++ % vq->vring.num];
709
710
/* If their number is silly, that's a fatal mistake. */
711
if (head >= vq->vring.num)
···
986
for (vq = dev->vq; vq; vq = vq->next) {
987
memset(vq->vring.desc, 0,
988
vring_size(vq->config.num, getpagesize()));
989
-
vq->last_avail_idx = 0;
990
}
991
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
992
warnx("Device %s configuration FAILED", dev->name);
···
191
return iov->iov_base;
192
}
193
194
+
/* Wrapper for the last available index. Makes it easier to change. */
195
+
#define lg_last_avail(vq) ((vq)->last_avail_idx)
196
+
197
/* The virtio configuration space is defined to be little-endian. x86 is
198
* little-endian too, but it's nice to be explicit so we have these helpers. */
199
#define cpu_to_le16(v16) (v16)
···
690
unsigned int *out_num, unsigned int *in_num)
691
{
692
unsigned int i, head;
693
+
u16 last_avail;
694
695
/* Check it isn't doing very strange things with descriptor numbers. */
696
+
last_avail = lg_last_avail(vq);
697
+
if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
698
errx(1, "Guest moved used index from %u to %u",
699
+
last_avail, vq->vring.avail->idx);
700
701
/* If there's nothing new since last we looked, return invalid. */
702
+
if (vq->vring.avail->idx == last_avail)
703
return vq->vring.num;
704
705
/* Grab the next descriptor number they're advertising, and increment
706
* the index we've seen. */
707
+
head = vq->vring.avail->ring[last_avail % vq->vring.num];
708
+
lg_last_avail(vq)++;
709
710
/* If their number is silly, that's a fatal mistake. */
711
if (head >= vq->vring.num)
···
980
for (vq = dev->vq; vq; vq = vq->next) {
981
memset(vq->vring.desc, 0,
982
vring_size(vq->config.num, getpagesize()));
983
+
lg_last_avail(vq) = 0;
984
}
985
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
986
warnx("Device %s configuration FAILED", dev->name);