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 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
