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Message-ID: <b69fa64d-9d84-d0ce-146e-09412e8f7862@redhat.com>
Date:   Wed, 6 Apr 2022 13:26:01 +0200
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Subject: Re: [RFC PATCH v5 033/104] KVM: x86: Add infrastructure for stolen
 GPA bits
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To:     Kai Huang <kai.huang@intel.com>, isaku.yamahata@intel.com,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@gmail.com, Jim Mattson <jmattson@google.com>,
        erdemaktas@google.com, Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>
References: <cover.1646422845.git.isaku.yamahata@intel.com>
 <a21c1f9065cf27db54820b2b504db4e507835584.1646422845.git.isaku.yamahata@intel.com>
 <2b8038c17b85658a054191b362840240bd66e46b.camel@intel.com>
 <5443b630-d2c8-b0c3-14f5-2b6b3f71221c@redhat.com>
 <f9cd6947441e43cc27a6b21a089da61bb7fed9b0.camel@intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <f9cd6947441e43cc27a6b21a089da61bb7fed9b0.camel@intel.com>
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On 4/6/22 04:23, Kai Huang wrote:
>>
>>>>
>>>>   
>>>> -		gfn = gpte_to_gfn(gpte);
>>>> +		gfn = gpte_to_gfn(vcpu, gpte);
>>>>   		pte_access = sp->role.access;
>>>>   		pte_access &= FNAME(gpte_access)(gpte);
>>>>   		FNAME(protect_clean_gpte)(vcpu->arch.mmu, &pte_access, gpte);
>>>
>>> In commit message you mentioned "Don't support stolen bits for shadow EPT" (you
>>> actually mean shadow MMU I suppose), yet there's bunch of code change to shadow
>>> MMU.
>>
>> It's a bit ugly, but it's uglier to keep two versions of gpte_to_gfn.
> 
> gpte_to_gfn() is only used in paging_tmpl.h.  Could you elaborate why we need to
> keep two versions of it?

You're right.  Yeah, considering page table walks are not supported when 
private memory is available, it shouldn't be necessary to change 
paging_tmpl.h.

Paolo