Fixed
Created: May 29, 2019
Updated: Sep 16, 2019
Resolved Date: Sep 9, 2019
Found In Version: 9.0.0.19
Fix Version: 9.0.0.23
Severity: Critical
Applicable for: Wind River Linux 9
Component/s: Kernel
The KVM / qemu version 2.7.0 that is bundled in WR9 has x2apic mode enabled by default, and this includes advertising directed-EOI capabilities in the local apic. However the in-kernel emulated IO APIC does not support the feature. If the guest OS enables directed EOI based on the advertised capabilities of local APIC, one of our WRL9 OVP customer encountered an interrupt storm on some pass-through devices that use level edge triggered interrupts, since broadcast EOIs are never processed.
The following fix seems related,
[https://patchwork.kernel.org/patch/10208945/]
Above patch is part of LTS18 but is not included in WRL9 yet.
NA
Issue is reproducible in customer env with WRL9 OVP RCPL0019 HOST + FreeBSD 11 GUEST. We can ask customer to validate hotfixes as issue is currently active in their setup.
Project configration:
--dl-layers --distros wrlinux-ovp --machines intel-x86-64 --templates feature/initramfs,feature/kdump,feature/kexec,feature/kernel-ovp-kvm,feature/sysklogd,feature/dpdk,feature/package-management --layers wr-kernel wr-ovp
Customer is using SMBus which is passed to the guest using PCI passthrough.
-> Host OS with version
Linux tahoma-node 4.8.28-rt10-WR9.0.0.19_ovp #1 SMP Mon Apr 8 20:53:27 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Linux host is not getting interrupt on the Smbus but qemu is sending interrupt to Guest at the rate of 21k/sec
Interrupt info on Guest OS,
root@tahoma:~ # vmstat -i
interrupt total rate
irq4: uart0 uart2 28406 0
irq11: ichsmb0 1443313461 22533
