From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Gleb Natapov <gleb@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 5/5] KVM: MMU: retry #PF for softmmu
Date: Mon, 15 Nov 2010 17:55:25 +0800 [thread overview]
Message-ID: <4CE1038D.9020403@cn.fujitsu.com> (raw)
In-Reply-To: <4CE0FDBC.20505@redhat.com>
On 11/15/2010 05:30 PM, Avi Kivity wrote:
>> Yeah, this 'retry' is unnecessary if the process is killed, but this
>> case is infrequent, the most case is the process keeps running and try
>> to access the fault address later.
>
> The problem is that if we retry in this case, we install an incorrect spte?
>
......
>> can avoid if the page mapping have been fixed.
>
> The guest may have changed page directories or other levels.
>
......
>> > Or another thread may have mmap()ed something else over the
>> > same address.
>>
>> The mmap virtual address is also visible for other threads since the
>> threads
>> have the same page table, so i think this case is the same as above?
>
> Again, don't we install the wrong spte in this case?
>
I think it doesn't corrupts spte since we will walk guest page table again
and map it to shadow pages when we retry #PF.
next prev parent reply other threads:[~2010-11-15 9:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-12 6:46 [PATCH v2 1/5] KVM: MMU: fix missing post sync audit Xiao Guangrong
2010-11-12 6:47 ` [PATCH v2 2/5] KVM: MMU: clear apfs if page state is changed Xiao Guangrong
2010-11-12 6:49 ` [PATCH v2 3/5] KVM: MMU: support apf for nonpaing guest Xiao Guangrong
2010-11-12 6:49 ` [PATCH v2 4/5] KVM: MMU: fix apf prefault if nested guest is enabled Xiao Guangrong
2010-11-12 6:50 ` [PATCH v2 5/5] KVM: MMU: retry #PF for softmmu Xiao Guangrong
2010-11-14 10:46 ` Avi Kivity
2010-11-15 5:25 ` Xiao Guangrong
2010-11-15 9:30 ` Avi Kivity
2010-11-15 9:55 ` Xiao Guangrong [this message]
2010-11-15 9:56 ` Gleb Natapov
2010-11-15 9:59 ` Avi Kivity
2010-11-15 10:12 ` Xiao Guangrong
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