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[Qemu-devel] [PATCH] e1000e: Prevent MSI/MSI-X storms
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH] e1000e: Prevent MSI/MSI-X storms |
Date: |
Sun, 1 Apr 2018 23:17:53 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
From: Jan Kiszka <address@hidden>
Only signal MSI/MSI-X events on rising edges. So far we re-triggered the
interrupt sources even if the guest did no consumed the pending one,
easily causing interrupt storms.
Issue was observable with Linux 4.16 e1000e driver when MSI-X was used.
Vector 2 was causing interrupt storms after the driver activated the
device.
Signed-off-by: Jan Kiszka <address@hidden>
---
hw/net/e1000e_core.c | 10 ++++++++++
hw/net/e1000e_core.h | 2 ++
2 files changed, 12 insertions(+)
diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
index c93c4661ed..ecf9b15555 100644
--- a/hw/net/e1000e_core.c
+++ b/hw/net/e1000e_core.c
@@ -2123,6 +2123,13 @@ e1000e_send_msi(E1000ECore *core, bool msix)
{
uint32_t causes = core->mac[ICR] & core->mac[IMS] & ~E1000_ICR_ASSERTED;
+ core->msi_causes_pending &= causes;
+ causes ^= core->msi_causes_pending;
+ if (causes == 0) {
+ return;
+ }
+ core->msi_causes_pending |= causes;
+
if (msix) {
e1000e_msix_notify(core, causes);
} else {
@@ -2160,6 +2167,9 @@ e1000e_update_interrupt_state(E1000ECore *core)
core->mac[ICS] = core->mac[ICR];
interrupts_pending = (core->mac[IMS] & core->mac[ICR]) ? true : false;
+ if (!interrupts_pending) {
+ core->msi_causes_pending = 0;
+ }
trace_e1000e_irq_pending_interrupts(core->mac[ICR] & core->mac[IMS],
core->mac[ICR], core->mac[IMS]);
diff --git a/hw/net/e1000e_core.h b/hw/net/e1000e_core.h
index 7d8ff41890..63a15510cc 100644
--- a/hw/net/e1000e_core.h
+++ b/hw/net/e1000e_core.h
@@ -109,6 +109,8 @@ struct E1000Core {
NICState *owner_nic;
PCIDevice *owner;
void (*owner_start_recv)(PCIDevice *d);
+
+ uint32_t msi_causes_pending;
};
void
--
2.13.6
- [Qemu-devel] [PATCH] e1000e: Prevent MSI/MSI-X storms,
Jan Kiszka <=