linux-kernel - Re: [PATCH] KVM: X86: Fix SMRAM accessing even if VM is shutdown

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Message-ID: <CANRm+CxQ29LpqPbzxUjJhM1-Yir0bMTnp=y_Ds2_+63zOSz0qQ@mail.gmail.com>
Date:   Sun, 11 Feb 2018 16:56:50 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Xiao Guangrong <guangrong.xiao@...il.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [PATCH] KVM: X86: Fix SMRAM accessing even if VM is shutdown

2018-02-11 11:20 GMT+08:00 Xiao Guangrong <guangrong.xiao@...il.com>:
>
>
> 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? :)

Thanks for the discussion, I will have a try. :)

Regards,
Wanpeng Li