linux-kernel - Re: [PATCH 15/15] KVM: X86: Always set gpte_is_8

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Message-ID: <bcfa0e4d-f6ab-037a-9ce1-d0cd612422a5@linux.alibaba.com>
Date:   Thu, 18 Nov 2021 22:34:54 +0800
From:   Lai Jiangshan <laijs@...ux.alibaba.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, Jonathan Corbet <corbet@....net>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, linux-doc@...r.kernel.org
Subject: Re: [PATCH 15/15] KVM: X86: Always set gpte_is_8_bytes when direct
 map



On 2021/11/18 19:12, Paolo Bonzini wrote:
> On 11/18/21 12:08, Lai Jiangshan wrote:
>> From: Lai Jiangshan <laijs@...ux.alibaba.com>
>>
>> When direct map, gpte_is_8_bytes has no meaning, but it is true for all
>> other cases except direct map when nonpaping.
>>
>> Setting gpte_is_8_bytes to true when nonpaping can ensure that
>> !gpte_is_8_bytes means 32-bit gptes for shadow paging.
> 
> Then the right thing to do would be to rename it to has_4_byte_gptes and invert the direction.  But as things stand, 
> it's a bit more confusing to make gpte_is_8_bytes=1 if there are no guest PTEs at all.
> 

I will make the last 3 patches be a separated patchset and will do the rename.