Re: [RFC PATCH v2 5/5] KVM: Unmap pages only when it's indeed protected for NUMA migration

[bibo mao]

在 2023/8/16 15:18, Yan Zhao 写道:
> On Wed, Aug 16, 2023 at 03:29:22PM +0800, bibo mao wrote:
>>> Flush must be done before kvm->mmu_lock is unlocked, otherwise,
>>> confusion will be caused when multiple threads trying to update the
>>> secondary MMU.
>> Since tlb flush is delayed after all pte entries are cleared, and currently
>> there is no tlb flush range supported for secondary mmu. I do know why there
>> is confusion before or after kvm->mmu_lock.
> 
> Oh, do you mean only do kvm_unmap_gfn_range() in .invalidate_range_end()?
yes, it is just sketchy thought for numa balance scenery, 
do kvm_unmap_gfn_range() in invalidate_range_end rather than
invalidate_range_start.
 
> Then check if PROT_NONE is set in primary MMU before unmap?
> Looks like a good idea, I need to check if it's feasible.
> Thanks!
> 
>