From: Paolo Bonzini <pbonzini@redhat.com>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] KVM: MMU: fix permission_fault()
Date: Wed, 30 Mar 2016 08:36:16 +0200 [thread overview]
Message-ID: <56FB73E0.7060601@redhat.com> (raw)
In-Reply-To: <56FB3254.5070403@linux.intel.com>
On 30/03/2016 03:56, Xiao Guangrong wrote:
>> x86/access.flat is currently using the "other" definition, i.e., PFEC.PK
>> is only set if W=1 or CR0.WP=0 && PFEC.U=0 or PFEC.W=0. Can you use it
>> (with ept=1 of course) to check what the processor is doing?
>
> Sure.
>
> And ept=1 is hard to trigger MMU issue, i am enabling PKEY on shadow
> MMU, let's see what will happen. ;)
No, don't do that!
ept=1 lets you test what the processor does. It means you cannot test
permission_fault(), but what we want here is just reverse engineering
the microcode. ept=1 lets you do exactly that.
Paolo
next prev parent reply other threads:[~2016-03-30 6:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-25 13:19 [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong
2016-03-25 13:19 ` [PATCH 2/4] KVM: MMU: simplify the logic of __mmu_unsync_walk() Xiao Guangrong
2016-03-25 13:19 ` [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Xiao Guangrong
2016-03-25 13:45 ` Paolo Bonzini
2016-03-25 13:48 ` Xiao Guangrong
2016-03-25 13:56 ` Paolo Bonzini
2016-03-25 14:07 ` Xiao Guangrong
2016-03-25 14:22 ` Paolo Bonzini
2016-03-25 13:19 ` [PATCH 4/4] KVM: MMU: skip obsolete sp in for_each_gfn_*() Xiao Guangrong
2016-03-29 9:44 ` Paolo Bonzini
2016-03-25 13:35 ` [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini
2016-03-25 13:41 ` Xiao Guangrong
2016-03-25 13:50 ` Paolo Bonzini
2016-03-25 14:21 ` Paolo Bonzini
2016-03-29 17:43 ` Xiao Guangrong
2016-03-29 20:09 ` Paolo Bonzini
2016-03-30 1:56 ` Xiao Guangrong
2016-03-30 6:36 ` Paolo Bonzini [this message]
2016-03-30 6:39 ` Xiao Guangrong
2016-04-06 3:27 ` Xiao Guangrong
2016-04-06 8:17 ` Paolo Bonzini
2016-04-06 8:56 ` Paolo Bonzini
2016-04-06 15:09 ` Xiao Guangrong
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