[PATCH] hw/display/xlnx_dp: fix overflow in xlnx_dp_aux_push_tx_fifo()

[Qiang Liu]

This patch checks if the s->tx_fifo is full.

Fixes: 58ac482a66de ("introduce xlnx-dp")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1424
Reported-by: Qiang Liu <cyruscyliu@gmail.com>
Signed-off-by: Qiang Liu <cyruscyliu@gmail.com>
---
 hw/display/xlnx_dp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
index 972473d94f..617b394af2 100644
--- a/hw/display/xlnx_dp.c
+++ b/hw/display/xlnx_dp.c
@@ -854,7 +854,11 @@ static void xlnx_dp_write(void *opaque, hwaddr offset, 
uint64_t value,
         break;
     case DP_AUX_WRITE_FIFO: {
         uint8_t c = value;
-        xlnx_dp_aux_push_tx_fifo(s, &c, 1);
+        if (fifo8_is_full(&s->tx_fifo)) {
+            qemu_log_mask(LOG_GUEST_ERROR, "xlnx_dp: TX fifo is full");
+        } else {
+            xlnx_dp_aux_push_tx_fifo(s, &c, 1);
+        }
         break;
     }
     case DP_AUX_CLOCK_DIVIDER:
-- 
2.25.1