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Subject: Re: [PATCH] KVM: X86: Fix SMRAM accessing even if VM is shutdown
To:     Paolo Bonzini <pbonzini@redhat.com>,
        Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Dmitry Vyukov <dvyukov@google.com>
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From:   Xiao Guangrong <guangrong.xiao@gmail.com>
Message-ID: <63c3626c-e64d-aa56-3935-be046d731232@gmail.com>
Date:   Sun, 11 Feb 2018 11:20:23 +0800
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On 02/09/2018 08:42 PM, Paolo Bonzini wrote:
> On 09/02/2018 04:22, Xiao Guangrong wrote:
>>>
>>
>> That is a good question... :)
>>
>> This case (with KVM_MEMSLOT_INVALID is set) can be easily constructed,
>> userspace should avoid this case by itself (avoiding vCPU accessing the
>> memslot which is being updated). If it happens, it's a operation issue
>> rather than INTERNAL ERROR.
>>
>> Maybe treat it as MMIO accessing and return to userspace with MMIO_EXIT
>> is a better solution...
> 
> Yeah, that's what emulation would do (except if it's an instruction
> fetch, which will cause emulation to fail).  I think it's a bug in the
> non-EPT #PF case that we return with -EFAULT.

Wanpeng, could you please do it? :)