Re: [PATCH] KVM: Veirfy memory slot only for readability

From: Takuya Yoshikawa
Date: Thu Dec 01 2011 - 22:16:00 EST


(2011/12/02 10:15), Takuya Yoshikawa wrote:
> (2011/12/02 4:42), Sasha Levin wrote:
>> It's enough for memory slot to be readable, as the comment above the check
>> states.
>>
>> A user should be able to create read-only memory slot.

Note: at that time, it looked to me that the API did not allow me to know
which type was being registered.

Do you want to create read only memory slots for kvm tool?

Takuya

>
> I submitted the original patch like you to speed up page table walking,
> a hot path in KVM, and Avi applied the patch with changing the VERIFY_READ
> to VERIFY_WRITE: on x86, both do the same check. You can see that on the
> commit.
>
> After that, Xiao started to write with __xxx_user() based on this check IIRC.
> So you should keep the code as is and change the comment if you like!
>
> Thanks,
> Takuya
>
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