linux-kernel - Re: [PATCH v3 07/11] KVM: page track: add notifier support

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Date:	Tue, 23 Feb 2016 15:16:25 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Cc:	gleb@...nel.org, mtosatti@...hat.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, kai.huang@...ux.intel.com,
	jike.song@...el.com
Subject: Re: [PATCH v3 07/11] KVM: page track: add notifier support



On 23/02/2016 05:34, Xiao Guangrong wrote:
>>
>> A kvm_vcpu_mark_page_dirty is missing here, isn't it?  I can take care
>> of it, but it would be great if you double-checked this.  If so, that
>> should be fixed in stable kernels too.
> 
> No. It's already been handled in emulator_write_phys() ->
> kvm_vcpu_write_guest()
> -> kvm_vcpu_write_guest_page() -> __kvm_write_guest_page().

You're right...

>>
>> Can you add a kvm_vcpu_note_page_write(vcpu, gpa, val, bytes) function
>> that takes care of calling kvm_vcpu_mark_page_dirty, kvm_mmu_pte_write
>> and kvm_page_track-write?
>>
> 
> After this patchset, kvm_mmu_pte_write is only a static notifier
> callback called
> by kvm_page_track_write().
> 
> And the dirty tracking in emulator_write_phys() is handled in a public
> API (as my
> explanation above), in emulator_cmpxchg_emulated is handled by itself.
> So i think
> it is better to leaving dirty tracking to the separate paths, no? :)

... and here it is indeed better to leave things as they are in v3.  Thanks,

Paolo