On 20.02.15 15:12, Paolo Bonzini wrote: > > > On 20/02/2015 14:45, Alexander Graf wrote: >> >> >> On 18.02.15 10:32, Bogdan Purcareata wrote: >>> 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. >> >> Thomas, what is the usual approach for patches like this? Do you take >> them into your rt tree or should they get integrated to upstream? > > Patch 1 is definitely suitable for upstream, that's the reason why we > have raw_spin_lock vs. raw_spin_unlock. I see, perfect :). Bogdan, please resend patch 1 with CC to kvm-ppc@vger so that I can pick it up from patchworks. Alex -- 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
