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SubjectRe: [PATCH 0/3] KVM: Make kvm_lock non-raw
On Mon, Sep 16, 2013 at 04:06:10PM +0200, 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?
>
Reviewed-by: Gleb Natapov <gleb@redhat.com>

But why should it go to stable?

> 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

--
Gleb.


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