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 05/12] KVM: x86: fast emulate repeat string write instructions
Date: Wed, 03 Aug 2011 17:31:06 +0800 [thread overview]
Message-ID: <4E39155A.6090704@cn.fujitsu.com> (raw)
In-Reply-To: <4E390283.6050106@redhat.com>
On 08/03/2011 04:10 PM, Avi Kivity wrote:
> On 08/02/2011 02:09 PM, Xiao Guangrong wrote:
>> We usually use repeat string instructions to clear the page, for example,
>> we call memset to clear a page table, stosb is used in this function, and
>> repeated for 1024 times, that means we should occupy mmu lock for 1024 times
>> and walking shadow page cache for 1024 times, it is terrible
>>
>> In fact, if it is the repeat string instructions emulated and it is not a
>> IO/MMIO access, we can zap all the corresponding shadow pages and return to the
>> guest, then the mapping can became writable and we can directly write the page
>>
>
> This isn't needed if we zap before emulating, right?
>
Yes, it is, i will improve it.
next prev parent reply other threads:[~2011-08-03 9:29 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
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 [this message]
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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