This patchset enables running KVM SMP guests with external interrupts on an underlying RT-enabled Linux. Previous to this patch, a guest with in-kernel MPIC emulation could easily panic the kernel due to preemption when delivering IPIs and external interrupts, because of the openpic spinlock becoming a sleeping mutex on PREEMPT_RT_FULL Linux. 0001: converts the openpic spinlock to a raw spinlock, in order to circumvent this behavior. While this change is targeted for a RT enabled Linux, it has no effect on upstream kvm-ppc, so send it upstream for better future maintenance. 0002: disables in-kernel MPIC emulation for guest running on RT, in order to prevent a potential DoS attack due to large system latencies. This patch is targeted to RT (due to CONFIG_PREEMPT_RT_FULL), but it can also be applied on upstream Linux, with no effect. - applied & compiled against vanilla 4.0 - applied & compiled against stable-rt 3.18-rt v2: - updated commit messages - change the fix for potentially large latencies from limiting the max number of VCPUs a guest can have to disabling the in-kernel MPIC Bogdan Purcareata (2): powerpc/kvm: Convert openpic lock to raw_spinlock powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT_FULL arch/powerpc/kvm/Kconfig | 1 + arch/powerpc/kvm/mpic.c | 44 ++++++++++++++++++++++---------------------- 2 files changed, 23 insertions(+), 22 deletions(-) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
