e1000.c doesn't properly emulate EERD and ICS registers

Once again, the emulation of the EERD and ICS registers in e1000.c is
incorrect. Nobody has noticed this before because none of the Intel-written
e1000 drivers use these registers, and all of the independently written open
source drivers copy Intel's example, so they don't use them either.
Regardless, these registers are documented in the programmer's manuals, and
their emulated behavior doesn't match the verified behavior of real hardware,
so any software that does use them doesn't function correctly.

-Bill

Signed-off-by: Bill Paul <wpaul@windriver.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/e1000.c

@@ -154,6 +154,7 @@ set_interrupt_cause(E1000State *s, int index, uint32_t val)
     if (val)
         val |= E1000_ICR_INT_ASSERTED;
     s->mac_reg[ICR] = val;
+    s->mac_reg[ICS] = val;
     qemu_set_irq(s->dev.irq[0], (s->mac_reg[IMS] & s->mac_reg[ICR]) != 0);
 }
 
@@ -286,10 +287,14 @@ flash_eerd_read(E1000State *s, int x)
 {
     unsigned int index, r = s->mac_reg[EERD] & ~E1000_EEPROM_RW_REG_START;
 
+    if ((s->mac_reg[EERD] & E1000_EEPROM_RW_REG_START) == 0)
+        return (s->mac_reg[EERD]);
+
     if ((index = r >> E1000_EEPROM_RW_ADDR_SHIFT) > EEPROM_CHECKSUM_REG)
-        return 0;
-    return (s->eeprom_data[index] << E1000_EEPROM_RW_REG_DATA) |
-           E1000_EEPROM_RW_REG_DONE | r;
+        return (E1000_EEPROM_RW_REG_DONE | r);
+
+    return ((s->eeprom_data[index] << E1000_EEPROM_RW_REG_DATA) |
+           E1000_EEPROM_RW_REG_DONE | r);
 }
 
 static void
@@ -780,7 +785,7 @@ static uint32_t (*macreg_readops[])(E1000State *, int) = {
     getreg(WUFC),	getreg(TDT),	getreg(CTRL),	getreg(LEDCTL),
     getreg(MANC),	getreg(MDIC),	getreg(SWSM),	getreg(STATUS),
     getreg(TORL),	getreg(TOTL),	getreg(IMS),	getreg(TCTL),
-    getreg(RDH),	getreg(RDT),	getreg(VET),
+    getreg(RDH),	getreg(RDT),	getreg(VET),	getreg(ICS),
 
     [TOTH] = mac_read_clr8,	[TORH] = mac_read_clr8,	[GPRC] = mac_read_clr4,
     [GPTC] = mac_read_clr4,	[TPR] = mac_read_clr4,	[TPT] = mac_read_clr4,