From: Avi Kivity <avi@redhat.com>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.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 11:09:03 +0300 [thread overview]
Message-ID: <4E39021F.8070508@redhat.com> (raw)
In-Reply-To: <4E38E477.2000208@cn.fujitsu.com>
On 08/03/2011 09:02 AM, Xiao Guangrong wrote:
> > 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.
Note it's a little dangerous. If the guest uses a non-page-table
modifying instruction on the PDE that points to the instruction, then we
will unmap the instruction and go to an infinite loop.
Maybe it's better to emulate if we can't find a fix for that.
One way would be to emulate every 20 instructions; this breaks us out of
the loop but reduces costly emulations to 5%.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-08-03 8:09 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 [this message]
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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