[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 2/7] virtio: guard against NULL pfn
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL 2/7] virtio: guard against NULL pfn |
Date: |
Wed, 15 Mar 2017 20:01:21 +0200 |
From: Jason Wang <address@hidden>
To avoid access stale memory region cache after reset, this patch
check the existence of virtqueue pfn for all exported virtqueue access
helpers before trying to use them.
Cc: Cornelia Huck <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Reviewed-by: Cornelia Huck <address@hidden>
Signed-off-by: Jason Wang <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
hw/virtio/virtio.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index efce4b3..9164579 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -318,6 +318,10 @@ int virtio_queue_ready(VirtQueue *vq)
* Called within rcu_read_lock(). */
static int virtio_queue_empty_rcu(VirtQueue *vq)
{
+ if (unlikely(!vq->vring.avail)) {
+ return 1;
+ }
+
if (vq->shadow_avail_idx != vq->last_avail_idx) {
return 0;
}
@@ -329,6 +333,10 @@ int virtio_queue_empty(VirtQueue *vq)
{
bool empty;
+ if (unlikely(!vq->vring.avail)) {
+ return 1;
+ }
+
if (vq->shadow_avail_idx != vq->last_avail_idx) {
return 0;
}
@@ -431,6 +439,10 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement
*elem,
return;
}
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
idx = (idx + vq->used_idx) % vq->vring.num;
uelem.id = elem->index;
@@ -448,6 +460,10 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
return;
}
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
/* Make sure buffer is written before we update index. */
smp_wmb();
trace_virtqueue_flush(vq, count);
@@ -546,6 +562,16 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int
*in_bytes,
int64_t len = 0;
int rc;
+ if (unlikely(!vq->vring.desc)) {
+ if (in_bytes) {
+ *in_bytes = 0;
+ }
+ if (out_bytes) {
+ *out_bytes = 0;
+ }
+ return;
+ }
+
rcu_read_lock();
idx = vq->last_avail_idx;
total_bufs = in_total = out_total = 0;
--
MST
- [Qemu-devel] [PULL 0/7] virtio, pc: fixes, Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 2/7] virtio: guard against NULL pfn,
Michael S. Tsirkin <=
- [Qemu-devel] [PULL 1/7] Bugfix: Handle error if VM Generation ID device not present, Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 3/7] virtio: destroy region cache during reset, Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 4/7] virtio: validate address space cache during init, Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 6/7] Revert "virtio: unbreak virtio-pci with IOMMU after caching ring translations", Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 5/7] pci: introduce a bus master container, Michael S. Tsirkin, 2017/03/15
- [Qemu-devel] [PULL 7/7] virtio-pci: reset modern vq meta data, Michael S. Tsirkin, 2017/03/15
- Re: [Qemu-devel] [PULL 0/7] virtio, pc: fixes, Peter Maydell, 2017/03/15