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

Avi Kivity
2011-08-02T12:20:40Z

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