Re: [PATCH v3 15/15] KVM: MMU: replace kvm_zap_all with kvm_mmu_invalid_all_pages

[Xiao Guangrong]

On 04/18/2013 08:08 AM, Marcelo Tosatti wrote:
> On Tue, Apr 16, 2013 at 02:32:53PM +0800, Xiao Guangrong wrote:
>> Use kvm_mmu_invalid_all_pages in kvm_arch_flush_shadow_all and
>> rename kvm_zap_all to kvm_free_all which is used to free all
>> memmory used by kvm mmu when vm is being destroyed, at this time,
>> no vcpu exists and mmu-notify has been unregistered, so we can
>> free the shadow pages out of mmu-lock
> 
> Since there is no contention for mmu-lock its also not a problem to 
> grab the lock right?

This still has contention. Other mmu-notify can happen when we handle
->release(). On the other handle, spin-lock is not preemptable.

> 
> Automated verification of locking/srcu might complain.

We hold slot-lock to free shadow page out of mmu-lock, it can avoid
the complain. No?



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