Re: [PATCH 0/7] KVM: Alleviate mmu_lock hold time when we startdirty logging

[Takuya Yoshikawa]

On Mon, 7 Jan 2013 18:36:42 -0200
Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote:

> Looks good, except patch 1 - 
> 
> a) don't understand why it is necessary and 

What's really necessary is to make sure that we don't call the function
for a deleted slot.  My explanation was wrong.

> b) not confident its safe - isnt clearing necessary for KVM_SET_MEMORY
> instances other than
> 
> !(old.flags & LOG_DIRTY) && (new.flags & LOG_DIRTY)

I think flushing shadows should be enough for other cases, e.g. moving a slot.

But I've changed the condition (see v2) to make it easier to understand:
  npages && LOG_DIRTY

Since remove_write_access() is for dirty logging, this condition should be safe.

Thanks,
	Takuya
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