[Qemu-devel] [PULL 26/37] net/cadence_gem: Fix small packet FCS stripping

[Peter Maydell]

From: Peter Crosthwaite <address@hidden>

The minimum packet size is 64, however this is before FCS stripping
occurs. So when FCS stripping the minimum packet size is 60. Fix.

Reported-by: Deepika Dhamija <address@hidden>
Signed-off-by: Peter Crosthwaite <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
---
 hw/net/cadence_gem.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index 2afafdf..1619507 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -687,6 +687,14 @@ static ssize_t gem_receive(NetClientState *nc, const 
uint8_t *buf, size_t size)
                  GEM_DMACFG_RBUFSZ_S) * GEM_DMACFG_RBUFSZ_MUL;
     bytes_to_copy = size;
 
+    /* Pad to minimum length. Assume FCS field is stripped, logic
+     * below will increment it to the real minimum of 64 when
+     * not FCS stripping
+     */
+    if (size < 60) {
+        size = 60;
+    }
+
     /* Strip of FCS field ? (usually yes) */
     if (s->regs[GEM_NWCFG] & GEM_NWCFG_STRIP_FCS) {
         rxbuf_ptr = (void *)buf;
@@ -713,11 +721,6 @@ static ssize_t gem_receive(NetClientState *nc, const 
uint8_t *buf, size_t size)
         size += 4;
     }
 
-    /* Pad to minimum length */
-    if (size < 64) {
-        size = 64;
-    }
-
     DB_PRINT("config bufsize: %d packet size: %ld\n", rxbufsize, size);
 
     while (bytes_to_copy) {
-- 
1.8.5