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: introduces a limit on the maximum VCPUs a guest can have, in order to prevent 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. Not sure if it's best to send it upstream and have a hanging CONFIG_PREEMPT_RT_FULL check there, with no effect, or send it against linux-stable-rt. Please apply as you consider appropriate. - applied & compiled against upstream 3.19 - applied & compiled against stable-rt 3.14-rt (0002 with minor fuzz) Bogdan Purcareata (2): powerpc/kvm: Convert openpic lock to raw_spinlock powerpc/kvm: Limit MAX_VCPUS for guests running on RT Linux arch/powerpc/include/asm/kvm_host.h | 6 +++++ arch/powerpc/kvm/mpic.c | 44 ++++++++++++++++++------------------- 2 files changed, 28 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
