linux-kernel - Re: [PATCH] KVM: x86: Fix the NULL pointer parameter in check_cr

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Date:   Wed, 20 Sep 2017 16:27:16 +0800
From:   Yu Zhang <yu.c.zhang@...ux.intel.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        David Hildenbrand <david@...hat.com>
Cc:     kvm list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] KVM: x86: Fix the NULL pointer parameter in
 check_cr_write()



On 9/20/2017 4:13 PM, Paolo Bonzini wrote:
> On 20/09/2017 08:35, Yu Zhang wrote:
>> 2 reasons I did not choose to change kvm_cpuid(): 1> like Jim's
>> comments, kvm_cpuid() will eventually write the *eax - *edx no
>> matter a cpuid entry is found or not; 2> currently, return value of
>> kvm_cpuid() is either true when an entry is found or false otherwise.
>> We can change kvm_cpuid() to check the pointers of GPRs against NULL
>> and return false immediately. Then the false value would have 2
>> different meanings - entry not found, or invalid params.
>>
>> Paolo, any suggestion? :-)
> Radim, has already sent this version to Linus. :)

Got it. Thanks. :)

Yu
> Paolo
>