[Qemu-devel] [PATCH v3] net: e1000e: fix an infinite loop issue

[Li Qiang <liq3ea@gmail.com>]

This issue is like the issue in e1000 network card addressed in
this commit:
e1000: eliminate infinite loops on out-of-bounds transfer start.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
---

Change since v2:
fix error in e1000e_ring_empty
eliminate unnecessory detect code in loop

Changes since v1:
make wraparound detect in e1000e_ring_empty

 hw/net/e1000e_core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
index 2b11499..dc94188 100644
--- a/hw/net/e1000e_core.c
+++ b/hw/net/e1000e_core.c
@@ -806,7 +806,8 @@ typedef struct E1000E_RingInfo_st {
 static inline bool
 e1000e_ring_empty(E1000ECore *core, const E1000E_RingInfo *r)
 {
-    return core->mac[r->dh] == core->mac[r->dt];
+    return core->mac[r->dh] == core->mac[r->dt] ||
+                core->mac[r->dt] >= core->mac[r->dlen] / E1000_RING_DESC_LEN;
 }
 
 static inline uint64_t
@@ -1522,6 +1523,10 @@ e1000e_write_packet_to_guest(E1000ECore *core, struct NetRxPkt *pkt,
             desc_size = core->rx_desc_buf_size;
         }
 
+        if (e1000e_ring_empty(core, rxi)) {
+            return;
+        }
+
         base = e1000e_ring_head_descr(core, rxi);
 
         pci_dma_read(d, base, &desc, core->rx_desc_len);
-- 
1.8.3.1