Re: [PATCH 02/11] KVM: x86: tag the instructions which are used towrite page table

From: Avi Kivity
Date: Mon Aug 22 2011 - 10:36:45 EST


On 08/22/2011 05:32 PM, Marcelo Tosatti wrote:
On Tue, Aug 16, 2011 at 02:41:27PM +0800, Xiao Guangrong wrote:
> The idea is from Avi:
> | tag instructions that are typically used to modify the page tables, and
> | drop shadow if any other instruction is used.
> | The list would include, I'd guess, and, or, bts, btc, mov, xchg, cmpxchg,
> | and cmpxchg8b.
>
> This patch is used to tag the instructions and in the later path, shadow page
> is dropped if it is written by other instructions

What is the advantage of doing this again? What is the point of
dropping shadow if the instruction is emulated?


So it won't be emulated again; the assumption is that if you addl into a page, it isn't a pagetable.

--
error compiling committee.c: too many arguments to function

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