[PATCH] e1000e: Added ICR clearing by corresponding IMS bit.

[Andrew Melnychenko <andrew@daynix.com>]

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1707441

The issue is in LSC clearing. So, after "link up"(during initialization),
the next LSC event is masked and can't be processed.
Technically, the event should be 'cleared' during ICR read.
On Windows guest, everything works well, mostly because of
different interrupt routines(ICR clears during register write).
So, added ICR clearing during reading, according to the note by
section 13.3.27 of the 8257X developers manual.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
---
 hw/net/e1000e_core.c | 10 ++++++++++
 hw/net/trace-events  |  1 +
 2 files changed, 11 insertions(+)

diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
index b75f2ab8fc..288897a975 100644
--- a/hw/net/e1000e_core.c
+++ b/hw/net/e1000e_core.c
@@ -2617,6 +2617,16 @@ e1000e_mac_icr_read(E1000ECore *core, int index)
         e1000e_clear_ims_bits(core, core->mac[IAM]);
     }
 
+    /*
+     * PCIe* GbE Controllers Open Source Software Developer's Manual
+     * 13.3.27 Interrupt Cause Read Register
+     */
+    if ((core->mac[ICR] & E1000_ICR_ASSERTED) &&
+        (core->mac[ICR] & core->mac[IMS])) {
+        trace_e1000e_irq_icr_clear_icr_bit_ims(core->mac[ICR], core->mac[IMS]);
+        core->mac[ICR] = 0;
+    }
+
     trace_e1000e_irq_icr_read_exit(core->mac[ICR]);
     e1000e_update_interrupt_state(core);
     return ret;
diff --git a/hw/net/trace-events b/hw/net/trace-events
index c28b91ee1a..15fd09aa1c 100644
--- a/hw/net/trace-events
+++ b/hw/net/trace-events
@@ -225,6 +225,7 @@ e1000e_irq_icr_read_entry(uint32_t icr) "Starting ICR read. Current ICR: 0x%x"
 e1000e_irq_icr_read_exit(uint32_t icr) "Ending ICR read. Current ICR: 0x%x"
 e1000e_irq_icr_clear_zero_ims(void) "Clearing ICR on read due to zero IMS"
 e1000e_irq_icr_clear_iame(void) "Clearing ICR on read due to IAME"
+e1000e_irq_icr_clear_icr_bit_ims(uint32_t icr, uint32_t ims) "Clearing ICR on read due corresponding IMS bit: 0x%x & 0x%x"
 e1000e_irq_iam_clear_eiame(uint32_t iam, uint32_t cause) "Clearing IMS due to EIAME, IAM: 0x%X, cause: 0x%X"
 e1000e_irq_icr_clear_eiac(uint32_t icr, uint32_t eiac) "Clearing ICR bits due to EIAC, ICR: 0x%X, EIAC: 0x%X"
 e1000e_irq_ims_clear_set_imc(uint32_t val) "Clearing IMS bits due to IMC write 0x%x"
-- 
2.31.1