hw/net/vmxnet3: Do not abort if the guest is trying to use an invalid TX queue

QEMU should never abort just because the guest is doing something odd.
Let's simply log the error and ignore the bad transmit queue instead.

Buglink: https://bugs.launchpad.net/qemu/+bug/1926111
Message-Id: <20210715103755.1035566-1-thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/net/vmxnet3.c

@@ -23,6 +23,7 @@
 #include "net/checksum.h"
 #include "sysemu/sysemu.h"
 #include "qemu/bswap.h"
+#include "qemu/log.h"
 #include "qemu/module.h"
 #include "hw/pci/msix.h"
 #include "hw/pci/msi.h"
@@ -1093,8 +1094,12 @@ vmxnet3_io_bar0_write(void *opaque, hwaddr addr,
         int tx_queue_idx =
             VMW_MULTIREG_IDX_BY_ADDR(addr, VMXNET3_REG_TXPROD,
                                      VMXNET3_REG_ALIGN);
-        assert(tx_queue_idx <= s->txq_num);
-        vmxnet3_process_tx_queue(s, tx_queue_idx);
+        if (tx_queue_idx <= s->txq_num) {
+            vmxnet3_process_tx_queue(s, tx_queue_idx);
+        } else {
+            qemu_log_mask(LOG_GUEST_ERROR, "vmxnet3: Illegal TX queue %d/%d\n",
+                          tx_queue_idx, s->txq_num);
+        }
         return;
     }