On 02/18/2015 10:32 AM, Bogdan Purcareata wrote: > Due to the introduction of the raw_spinlock for the KVM openpic, guests with a > high number of VCPUs may induce great latencies on the underlying RT Linux > system (e.g. cyclictest reports latencies of ~15ms for guests with 24 VCPUs). > This can be further aggravated by sending a lot of external interrupts to the > guest. > > A malicious app can abuse this scenario, causing a DoS of the host Linux. > Until the KVM openpic code is refactored to use finer lock granularity, impose > a limitation on the number of VCPUs a guest can have when running on a > PREEMPT_RT_FULL system with KVM_MPIC emulation.
How is this possible? You take the raw lock, write a register, release the raw lock. How can the guest lockup the host? Is this write blocking in guest? Sebastian _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
