vhost was dong some complex math to get offset to log at, and got it wrong by a couple of bytes, while in fact it's simple: get address where we write, subtract start of buffer, add log base.
Do it this way. Signed-off-by: Michael S. Tsirkin <[email protected]> --- drivers/vhost/vhost.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 6eb1525..c767279 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1004,10 +1004,12 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) if (unlikely(vq->log_used)) { /* Make sure data is seen before log. */ smp_wmb(); - log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring * - (vq->last_used_idx % vq->num), - sizeof *vq->used->ring); - log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring); + log_write(vq->log_base, + vq->log_addr + ((void *)used - (void *)vq->used), + sizeof *used); + log_write(vq->log_base, + vq->log_addr + offsetof(struct vring_used, idx), + sizeof vq->used->idx); if (vq->log_ctx) eventfd_signal(vq->log_ctx, 1); } -- 1.7.0.18.g0d53a5 _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
