[PATCH v2 4/9] igb: add ICR_RXDW

[Sriram Yagnaraman <sriram.yagnaraman@est.tech>]

IGB uses RXDW ICR bit to indicate that rx descriptor has been written
back. This is the same as RXT0 bit in older HW.

Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
---
 hw/net/e1000x_regs.h |  4 ++++
 hw/net/igb_core.c    | 28 ++++++++++++++--------------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/hw/net/e1000x_regs.h b/hw/net/e1000x_regs.h
index bb3fb36b8d..3a3431d878 100644
--- a/hw/net/e1000x_regs.h
+++ b/hw/net/e1000x_regs.h
@@ -335,6 +335,7 @@
 #define E1000_ICR_RXDMT0        0x00000010 /* rx desc min. threshold (0) */
 #define E1000_ICR_RXO           0x00000040 /* rx overrun */
 #define E1000_ICR_RXT0          0x00000080 /* rx timer intr (ring 0) */
+#define E1000_ICR_RXDW          0x00000080 /* rx desc written back */
 #define E1000_ICR_MDAC          0x00000200 /* MDIO access complete */
 #define E1000_ICR_RXCFG         0x00000400 /* RX /c/ ordered set */
 #define E1000_ICR_GPI_EN0       0x00000800 /* GP Int 0 */
@@ -378,6 +379,7 @@
 #define E1000_ICS_RXDMT0    E1000_ICR_RXDMT0    /* rx desc min. threshold */
 #define E1000_ICS_RXO       E1000_ICR_RXO       /* rx overrun */
 #define E1000_ICS_RXT0      E1000_ICR_RXT0      /* rx timer intr */
+#define E1000_ICS_RXDW      E1000_ICR_RXDW      /* rx desc written back */
 #define E1000_ICS_MDAC      E1000_ICR_MDAC      /* MDIO access complete */
 #define E1000_ICS_RXCFG     E1000_ICR_RXCFG     /* RX /c/ ordered set */
 #define E1000_ICS_GPI_EN0   E1000_ICR_GPI_EN0   /* GP Int 0 */
@@ -407,6 +409,7 @@
 #define E1000_IMS_RXDMT0    E1000_ICR_RXDMT0    /* rx desc min. threshold */
 #define E1000_IMS_RXO       E1000_ICR_RXO       /* rx overrun */
 #define E1000_IMS_RXT0      E1000_ICR_RXT0      /* rx timer intr */
+#define E1000_IMS_RXDW      E1000_ICR_RXDW      /* rx desc written back */
 #define E1000_IMS_MDAC      E1000_ICR_MDAC      /* MDIO access complete */
 #define E1000_IMS_RXCFG     E1000_ICR_RXCFG     /* RX /c/ ordered set */
 #define E1000_IMS_GPI_EN0   E1000_ICR_GPI_EN0   /* GP Int 0 */
@@ -441,6 +444,7 @@
 #define E1000_IMC_RXDMT0    E1000_ICR_RXDMT0    /* rx desc min. threshold */
 #define E1000_IMC_RXO       E1000_ICR_RXO       /* rx overrun */
 #define E1000_IMC_RXT0      E1000_ICR_RXT0      /* rx timer intr */
+#define E1000_IMC_RXDW      E1000_ICR_RXDW      /* rx desc written back */
 #define E1000_IMC_MDAC      E1000_ICR_MDAC      /* MDIO access complete */
 #define E1000_IMC_RXCFG     E1000_ICR_RXCFG     /* RX /c/ ordered set */
 #define E1000_IMC_GPI_EN0   E1000_ICR_GPI_EN0   /* GP Int 0 */
diff --git a/hw/net/igb_core.c b/hw/net/igb_core.c
index b8c01cb773..cea7c036f0 100644
--- a/hw/net/igb_core.c
+++ b/hw/net/igb_core.c
@@ -1498,7 +1498,7 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
     static const int maximum_ethernet_hdr_len = (ETH_HLEN + 4);
 
     uint16_t queues = 0;
-    uint32_t n = 0;
+    uint32_t icr_bits = 0;
     uint8_t min_buf[ETH_ZLEN];
     struct iovec min_iov;
     struct eth_header *ehdr;
@@ -1508,7 +1508,7 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
     E1000E_RxRing rxr;
     E1000E_RSSInfo rss_info;
     size_t total_size;
-    ssize_t retval;
+    ssize_t retval = 0;
     int i;
 
     trace_e1000e_rx_receive_iov(iovcnt);
@@ -1570,8 +1570,6 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
     total_size = net_rx_pkt_get_total_len(core->rx_pkt) +
         e1000x_fcs_len(core->mac);
 
-    retval = orig_size;
-
     for (i = 0; i < IGB_NUM_QUEUES; i++) {
         if (!(queues & BIT(i))) {
             continue;
@@ -1579,11 +1577,12 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
 
         igb_rx_ring_init(core, &rxr, i);
         if (!igb_has_rxbufs(core, rxr.i, total_size)) {
-            retval = 0;
+            icr_bits |= E1000_ICS_RXO;
         }
     }
 
-    if (retval) {
+    if (!icr_bits) {
+        retval = orig_size;
         igb_rx_fix_l4_csum(core, core->rx_pkt);
 
         for (i = 0; i < IGB_NUM_QUEUES; i++) {
@@ -1593,28 +1592,29 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
             }
 
             igb_rx_ring_init(core, &rxr, i);
+
             trace_e1000e_rx_rss_dispatched_to_queue(rxr.i->idx);
             igb_write_packet_to_guest(core, core->rx_pkt, &rxr, &rss_info);
 
             /* Check if receive descriptor minimum threshold hit */
             if (igb_rx_descr_threshold_hit(core, rxr.i)) {
-                n |= E1000_ICS_RXDMT0;
+                icr_bits |= E1000_ICS_RXDMT0;
             }
 
             core->mac[EICR] |= igb_rx_wb_eic(core, rxr.i->idx);
 
-            /* same as RXDW (rx descriptor written back)*/
-            n = E1000_ICR_RXT0;
+            icr_bits |= E1000_ICR_RXDW;
         }
+    }
 
-        trace_e1000e_rx_written_to_guest(n);
+    if (icr_bits & E1000_ICR_RXDW) {
+        trace_e1000e_rx_written_to_guest(icr_bits);
     } else {
-        n = E1000_ICS_RXO;
-        trace_e1000e_rx_not_written_to_guest(n);
+        trace_e1000e_rx_not_written_to_guest(icr_bits);
     }
 
-    trace_e1000e_rx_interrupt_set(n);
-    igb_set_interrupt_cause(core, n);
+    trace_e1000e_rx_interrupt_set(icr_bits);
+    igb_set_interrupt_cause(core, icr_bits);
 
     return retval;
 }
-- 
2.34.1