On 13-09-16 10:06 AM, Paolo Bonzini wrote: > Paul Gortmaker reported a BUG on preempt-rt kernels, due to taking the > mmu_lock within the raw kvm_lock in mmu_shrink_scan. He provided a > patch that shrunk the kvm_lock critical section so that the mmu_lock > critical section does not nest with it, but in the end there is no reason > for the vm_list to be protected by a raw spinlock. Only manipulations > of kvm_usage_count and the consequent hardware_enable/disable operations > are not preemptable. > > This small series thus splits the kvm_lock in the "raw" part and the > "non-raw" part. > > Paul, could you please provide your Tested-by? Sure, I'll go back and see if I can find what triggered it in the original report, and give the patches a spin on 3.4.x-rt (and probably 3.10.x-rt, since that is where rt-current is presently). Paul. -- > > Thanks, > > Paolo > > Paolo Bonzini (3): > KVM: cleanup (physical) CPU hotplug > KVM: protect kvm_usage_count with its own spinlock > KVM: Convert kvm_lock back to non-raw spinlock > > Documentation/virtual/kvm/locking.txt | 8 ++++-- > arch/x86/kvm/mmu.c | 4 +-- > arch/x86/kvm/x86.c | 8 +++--- > include/linux/kvm_host.h | 2 +- > virt/kvm/kvm_main.c | 51 ++++++++++++++++++----------------- > 5 files changed, 40 insertions(+), 33 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
