Declare RX registers as MMIO region, split it out
of the current mixed RAM/MMIO region.
The memory flat view becomes:

  (qemu) info mtree -f
  FlatView #0
   Root memory region: system
    0000000081000000-00000000810007e3 (prio 0, i/o): xlnx.xps-ethernetlite
    00000000810007e4-00000000810007f3 (prio 0, i/o): ethlite.mdio
    00000000810007f4-00000000810017fb (prio 0, i/o): xlnx.xps-ethernetlite @00000000000007f4
    00000000810017fc-00000000810017ff (prio 0, i/o): ethlite.rx[0]io
    0000000081001800-0000000081001ffb (prio 0, i/o): xlnx.xps-ethernetlite @0000000000001800
    0000000081001ffc-0000000081001fff (prio 0, i/o): ethlite.rx[1]io

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/net/xilinx_ethlite.c | 82 +++++++++++++++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 15 deletions(-)

diff --git a/hw/net/xilinx_ethlite.c b/hw/net/xilinx_ethlite.c
index 674f805d76..d8f5a06182 100644
--- a/hw/net/xilinx_ethlite.c
+++ b/hw/net/xilinx_ethlite.c
@@ -49,11 +49,16 @@
 #define R_TX_CTRL1    (0x0ffc / 4)
 
 #define R_RX_BUF0     (0x1000 / 4)
-#define R_RX_CTRL0    (0x17fc / 4)
+#define A_RX_BASE0     0x17fc
 #define R_RX_BUF1     (0x1800 / 4)
-#define R_RX_CTRL1    (0x1ffc / 4)
+#define A_RX_BASE1     0x1ffc
 #define R_MAX         (0x2000 / 4)
 
+enum {
+    RX_CTRL = 0,
+    RX_MAX
+};
+
 #define GIE_GIE    0x80000000
 
 #define CTRL_I     0x8
@@ -62,6 +67,8 @@
 
 typedef struct XlnxXpsEthLitePort
 {
+    MemoryRegion rxio;
+
     struct {
         uint32_t tx_len;
         uint32_t tx_gie;
@@ -119,6 +126,55 @@ static void *rxbuf_ptr(XlnxXpsEthLite *s, unsigned port_index)
     return &s->regs[rxbase + R_RX_BUF0];
 }
 
+static uint64_t port_rx_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    XlnxXpsEthLite *s = opaque;
+    unsigned port_index = addr_to_port_index(addr);
+    uint32_t r = 0;
+
+    switch (addr >> 2) {
+        case RX_CTRL:
+            r = s->port[port_index].reg.rx_ctrl;
+            break;
+        default:
+            g_assert_not_reached();
+    }
+
+    return r;
+}
+
+static void port_rx_write(void *opaque, hwaddr addr, uint64_t value,
+                          unsigned int size)
+{
+    XlnxXpsEthLite *s = opaque;
+    unsigned port_index = addr_to_port_index(addr);
+
+    switch (addr >> 2) {
+        case RX_CTRL:
+            if (!(value & CTRL_S)) {
+                qemu_flush_queued_packets(qemu_get_queue(s->nic));
+            }
+            s->port[port_index].reg.rx_ctrl = value;
+            break;
+        default:
+            g_assert_not_reached();
+    }
+}
+
+static const MemoryRegionOps eth_portrx_ops = {
+        .read = port_rx_read,
+        .write = port_rx_write,
+        .endianness = DEVICE_NATIVE_ENDIAN,
+        .impl = {
+            .min_access_size = 4,
+            .max_access_size = 4,
+        },
+        .valid = {
+            .min_access_size = 4,
+            .max_access_size = 4,
+        },
+};
+
 static uint64_t
 eth_read(void *opaque, hwaddr addr, unsigned int size)
 {
@@ -144,11 +200,6 @@ eth_read(void *opaque, hwaddr addr, unsigned int size)
             r = s->port[port_index].reg.tx_ctrl;
             break;
 
-        case R_RX_CTRL1:
-        case R_RX_CTRL0:
-            r = s->port[port_index].reg.rx_ctrl;
-            break;
-
         default:
             r = tswap32(s->regs[addr]);
             break;
@@ -189,14 +240,6 @@ eth_write(void *opaque, hwaddr addr,
             break;
 
         /* Keep these native.  */
-        case R_RX_CTRL0:
-        case R_RX_CTRL1:
-            if (!(value & CTRL_S)) {
-                qemu_flush_queued_packets(qemu_get_queue(s->nic));
-            }
-            s->port[port_index].reg.rx_ctrl = value;
-            break;
-
         case R_TX_LEN0:
         case R_TX_LEN1:
             s->port[port_index].reg.tx_len = value;
@@ -289,6 +332,15 @@ static void xilinx_ethlite_realize(DeviceState *dev, Error **errp)
     memory_region_add_subregion(&s->mmio, A_MDIO_BASE,
                            sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->mdio), 0));
 
+    for (unsigned i = 0; i < 2; i++) {
+        memory_region_init_io(&s->port[i].rxio, OBJECT(dev),
+                              &eth_portrx_ops, s,
+                              i ? "ethlite.rx[1]io" : "ethlite.rx[0]io",
+                              4 * RX_MAX);
+        memory_region_add_subregion(&s->mmio, i ? A_RX_BASE1 : A_RX_BASE0,
+                                    &s->port[i].rxio);
+    }
+
     qemu_macaddr_default_if_unset(&s->conf.macaddr);
     s->nic = qemu_new_nic(&net_xilinx_ethlite_info, &s->conf,
                           object_get_typename(OBJECT(dev)), dev->id,
-- 
2.45.2