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From: Avi Kivity <avi@qumranet.com>
To: Joerg Rodel <joerg.roedel@amd.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, stable@kernel.org,
	Alexander Graf <agraf@suse.de>
Subject: Re: [PATCH] KVM: SVM: fix random segfaults with NPT enabled
Date: Wed, 27 Aug 2008 19:49:29 +0300	[thread overview]
Message-ID: <48B58599.1040509@qumranet.com> (raw)
In-Reply-To: <20080827162715.GA28498@amd.com>

Joerg Rodel wrote:
>> Meanwhile, I applied the patch, but I'm very worried about this.
>>     
>
> Yes, we are also worried. Another question is why this only happens with
> NPT. The SoftMMU code should also fail with shadow paging if there is a
> bug.
>   

Slightly different paths -- direct_map vs page_fault.  Also, with npt, 
all cpus will access the same pte that's being modified; without npt, 
faults on the same page will result in different ptes being 
instantiated, as each access will be from a different guest pte.

Maybe we should turn on the dirty bit in the instantiated ptes -- that 
will reduce the processor's mucking about with them.

-- 
error compiling committee.c: too many arguments to function


  reply	other threads:[~2008-08-27 16:49 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-27 12:18 [PATCH] KVM: SVM: fix random segfaults with NPT enabled Joerg Rodel
2008-08-27 13:11 ` Avi Kivity
2008-08-27 13:53   ` Avi Kivity
2008-08-27 13:57     ` Joerg Rodel
2008-08-27 15:22       ` Avi Kivity
2008-08-27 15:35         ` Joerg Roedel
2008-08-27 15:50           ` Avi Kivity
2008-08-27 16:27             ` Joerg Rodel
2008-08-27 16:49               ` Avi Kivity [this message]
2008-08-27 16:59                 ` Avi Kivity
2008-08-28 14:58                   ` Joerg Rodel
2008-08-28 15:15                     ` Avi Kivity
2008-08-28 15:19                       ` Joerg Roedel
2008-08-28 15:47                         ` Avi Kivity
2008-08-28 15:29                       ` Avi Kivity
2008-08-28 15:58                         ` Joerg Roedel
2008-08-27 13:53   ` Joerg Rodel
2008-08-27 15:21     ` Avi Kivity
2008-08-27 15:32       ` Joerg Roedel

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