From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 02/12] KVM: x86: tag the instructions which are used to write page table
Date: Wed, 03 Aug 2011 14:02:31 +0800 [thread overview]
Message-ID: <4E38E477.2000208@cn.fujitsu.com> (raw)
In-Reply-To: <4E37EB8E.6080207@redhat.com>
On 08/02/2011 08:20 PM, Avi Kivity wrote:
> 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?
>
OK, will do it in the next version.
> 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.
>
This is a interesting feature. If it happens, i will just drop the shadow pages
and retry these instructions directly.
next prev parent reply other threads:[~2011-08-03 6:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-02 11:06 [PATCH v2 01/12] KVM: MMU: avoid pte_list_desc run out in kvm_mmu_pte_write Xiao Guangrong
2011-08-02 11:07 ` [PATCH v2 02/12] KVM: x86: tag the instructions which are used to write page table Xiao Guangrong
2011-08-02 12:20 ` Avi Kivity
2011-08-03 6:02 ` Xiao Guangrong [this message]
2011-08-03 8:09 ` Avi Kivity
2011-08-03 9:24 ` Xiao Guangrong
2011-08-03 9:25 ` Avi Kivity
2011-08-03 9:41 ` Xiao Guangrong
2011-08-03 9:40 ` Avi Kivity
2011-08-02 11:08 ` [PATCH v2 03/12] zap sp if it is written by unaware instructions Xiao Guangrong
2011-08-02 11:08 ` [PATCH v2 04/12] KVM: x86: cleanup port-in/port-out emulated Xiao Guangrong
2011-08-02 11:09 ` [PATCH v2 05/12] KVM: x86: fast emulate repeat string write instructions Xiao Guangrong
2011-08-03 8:10 ` Avi Kivity
2011-08-03 9:31 ` Xiao Guangrong
2011-08-02 11:09 ` [PATCH v2 06/12] KVM: MMU: do not mark access bit on pte write path Xiao Guangrong
2011-08-02 11:10 ` [PATCH v2 07/12] KVM: MMU: cleanup FNAME(invlpg) Xiao Guangrong
2011-08-02 11:10 ` [PATCH v2 08/12] KVM: MMU: fast prefetch spte on invlpg path Xiao Guangrong
2011-08-02 18:36 ` Marcelo Tosatti
2011-08-03 6:03 ` Xiao Guangrong
2011-08-02 11:11 ` [PATCH v2 09/12] KVM: MMU: remove unnecessary kvm_mmu_free_some_pages Xiao Guangrong
2011-08-02 11:11 ` [PATCH v2 10/12] KVM: MMU: split kvm_mmu_pte_write function Xiao Guangrong
2011-08-02 11:12 ` [PATCH v2 11/12] KVM: MMU: fix detecting misaligned accessed Xiao Guangrong
2011-08-02 11:13 ` [PATCH v2 12/12] KVM: MMU: improve write flooding detected Xiao Guangrong
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