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-rw-r--r--pc-bios/s390-ccw/virtio.c7
-rw-r--r--pc-bios/s390-ccw/virtio.h1
2 files changed, 5 insertions, 3 deletions
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 49f2d291fc..4d6e48fcbe 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -123,6 +123,7 @@ static void vring_init(struct vring *vr, unsigned int num, void *p,
/* We're running with interrupts off anyways, so don't bother */
vr->used->flags = VRING_USED_F_NO_NOTIFY;
vr->used->idx = 0;
+ vr->used_idx = 0;
debug_print_addr("init vr", vr);
}
@@ -150,8 +151,6 @@ static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
if (!(flags & VRING_DESC_F_NEXT)) {
vr->avail->idx++;
}
-
- vr->used->idx = vr->next_idx;
}
static u64 get_clock(void)
@@ -180,7 +179,8 @@ static int vring_wait_reply(struct vring *vr, int timeout)
struct subchannel_id schid = vr->schid;
int r = 0;
- while (vr->used->idx == vr->next_idx) {
+ /* Wait until the used index has moved. */
+ while (vr->used->idx == vr->used_idx) {
vring_notify(schid);
if (timeout && (get_second() >= target_second)) {
r = 1;
@@ -189,6 +189,7 @@ static int vring_wait_reply(struct vring *vr, int timeout)
yield();
}
+ vr->used_idx = vr->used->idx;
vr->next_idx = 0;
vr->desc[0].len = 0;
vr->desc[0].flags = 0;
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index 86fdd579b4..772a63f152 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -115,6 +115,7 @@ struct vring_used {
struct vring {
unsigned int num;
int next_idx;
+ int used_idx;
struct vring_desc *desc;
struct vring_avail *avail;
struct vring_used *used;