diff options
| -rw-r--r-- | hw/e1000.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/hw/e1000.c b/hw/e1000.c index ef06ca1894..ee85c53d38 100644 --- a/hw/e1000.c +++ b/hw/e1000.c @@ -237,7 +237,17 @@ set_interrupt_cause(E1000State *s, int index, uint32_t val) val |= E1000_ICR_INT_ASSERTED; } s->mac_reg[ICR] = val; + + /* + * Make sure ICR and ICS registers have the same value. + * The spec says that the ICS register is write-only. However in practice, + * on real hardware ICS is readable, and for reads it has the same value as + * ICR (except that ICS does not have the clear on read behaviour of ICR). + * + * The VxWorks PRO/1000 driver uses this behaviour. + */ s->mac_reg[ICS] = val; + qemu_set_irq(s->dev.irq[0], (s->mac_reg[IMS] & s->mac_reg[ICR]) != 0); } |