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| author | Ake Koomsin <ake@igel.co.jp> | 2022-07-20 20:13:03 +0900 |
|---|---|---|
| committer | Jason Wang <jasowang@redhat.com> | 2022-07-26 16:23:54 +0800 |
| commit | dd0ef128669c29734a197ca9195e7ab64e20ba2c (patch) | |
| tree | f9c197f3e9042dc6bf52eef6254fedae177b0675 | |
| parent | 5288bee45fbd33203b61f8c76e41b15bb5913e6e (diff) | |
| download | qemu-dd0ef128669c29734a197ca9195e7ab64e20ba2c.zip qemu-dd0ef128669c29734a197ca9195e7ab64e20ba2c.tar.gz qemu-dd0ef128669c29734a197ca9195e7ab64e20ba2c.tar.bz2 | |
e1000e: Fix possible interrupt loss when using MSI
Commit "e1000e: Prevent MSI/MSI-X storms" introduced msi_causes_pending
to prevent interrupt storms problem. It was tested with MSI-X.
In case of MSI, the guest can rely solely on interrupts to clear ICR.
Upon clearing all pending interrupts, msi_causes_pending gets cleared.
However, when e1000e_itr_should_postpone() in e1000e_send_msi() returns
true, MSI never gets fired by e1000e_intrmgr_on_throttling_timer()
because msi_causes_pending is still set. This results in interrupt loss.
To prevent this, we need to clear msi_causes_pending when MSI is going
to get fired by the throttling timer. The guest can then receive
interrupts eventually.
Signed-off-by: Ake Koomsin <ake@igel.co.jp>
Signed-off-by: Jason Wang <jasowang@redhat.com>
| -rw-r--r-- | hw/net/e1000e_core.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c index 2c51089..208e3e0 100644 --- a/hw/net/e1000e_core.c +++ b/hw/net/e1000e_core.c @@ -159,6 +159,8 @@ e1000e_intrmgr_on_throttling_timer(void *opaque) if (msi_enabled(timer->core->owner)) { trace_e1000e_irq_msi_notify_postponed(); + /* Clear msi_causes_pending to fire MSI eventually */ + timer->core->msi_causes_pending = 0; e1000e_set_interrupt_cause(timer->core, 0); } else { trace_e1000e_irq_legacy_notify_postponed(); |