Re: [PATCH v2 02/12] KVM: x86: tag the instructions which are usedto write page table

From: Avi Kivity
Date: Tue Aug 02 2011 - 08:20:43 EST


On 08/02/2011 02:07 PM, 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

We already have a mechanism for this, the decode tables. Why not add a new flag, PageTable, and set it on all relevant instructions?

Note we don't need to actually emulate, just decode, since page_fault can tell us whether a write failed due to page tables or mmio.


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

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