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? 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(-) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
