On 07.08.2025 14:08, Laurent Vivier wrote:
A race condition between guest driver actions and QEMU timers can lead
to an assertion failure when the guest switches the e1000e from legacy
interrupt mode to MSI-X. If a legacy interrupt delay timer (TIDV or
RDTR) is active, but the guest enables MSI-X before the timer fires,
the pending interrupt cause can trigger an assert in
e1000e_intmgr_collect_delayed_causes().
This patch removes the assertion and executes the code that clears the
pending legacy causes. This change is safe and introduces no unintended
behavioral side effects, as it only alters a state that previously led
to termination.
- when core->delayed_causes == 0 the function was already a no-op and
remains so.
- when core->delayed_causes != 0 the function would previously
crash due to the assertion failure. The patch now defines a safe
outcome by clearing the cause and returning. Since behavior after
the assertion never existed, this simply corrects the crash.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1863
Suggested-by: Akihiko Odaki <[email protected]>
Signed-off-by: Laurent Vivier <[email protected]>
It feels like this is a qemu-stable material. Picking it up for
10.0 & 10.1. And for 7.2 too.
Please let me know if I shouldn't.
Thanks,
/mjt
diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
index 24138587905b..06657bb3ac5c 100644
--- a/hw/net/e1000e_core.c
+++ b/hw/net/e1000e_core.c
@@ -341,11 +341,6 @@ e1000e_intmgr_collect_delayed_causes(E1000ECore *core)
{
uint32_t res;
- if (msix_enabled(core->owner)) {
- assert(core->delayed_causes == 0);
- return 0;
- }
-
res = core->delayed_causes;
core->delayed_causes = 0;
