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    SubjectRe: [PATCH 0/3] KVM: Make kvm_lock non-raw
    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(-)
    >


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