From ea9b03c57eec92f184b7d24a5086e1f335866c29 Mon Sep 17 00:00:00 2001 From: Bogdan Purcareata Date: Mon, 18 May 2015 13:13:54 +0000 Subject: powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT_FULL Current in-kernel MPIC emulation for PowerPC is unsuitable for RT. More specifically, the MPIC lock becomes a sleeping mutex, causing concurrency issues on a KVM guest enter. Converting the lock to a raw_spinlock is still not a viable solution, since the current implementation is prone to induce large latencies with preemption and irqs disabled on the host kernel. Patch aready applied in the upstream 3.18.13 RT patch, version 9 [1]. [1] http://www.spinics.net/lists/linux-rt-users/msg13340.html Signed-off-by: Bogdan Purcareata Change-Id: Ie942de00717527ea78c2471f6a5153489f432e89 Reviewed-on: http://git.am.freescale.net:8181/36530 Tested-by: Review Code-CDREVIEW Reviewed-by: Scott Wood Reviewed-by: Honghua Yin diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index ffaef2c..78c3c30 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -155,6 +155,7 @@ config KVM_E500MC config KVM_MPIC bool "KVM in-kernel MPIC emulation" depends on KVM && E500 + depends on !PREEMPT_RT_FULL select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQ_ROUTING select HAVE_KVM_MSI -- cgit v0.10.2