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Subject: Re: [RFC KVM 03/27] KVM: x86: Introduce KVM separate virtual address
 space
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Radim Krcmar <rkrcmar@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        kvm list <kvm@vger.kernel.org>, X86 ML <x86@kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        jan.setjeeilers@oracle.com, Liran Alon <liran.alon@oracle.com>,
        Jonathan Adams <jwadams@google.com>
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From:   Alexandre Chartre <alexandre.chartre@oracle.com>
Organization: Oracle Corporation
Message-ID: <8dba7da4-8087-1d80-5b60-fe651a930bb8@oracle.com>
Date:   Mon, 13 May 2019 18:04:44 +0200
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On 5/13/19 5:45 PM, Andy Lutomirski wrote:
> On Mon, May 13, 2019 at 7:39 AM Alexandre Chartre
> <alexandre.chartre@oracle.com> wrote:
>>
>> From: Liran Alon <liran.alon@oracle.com>
>>
>> Create a separate mm for KVM that will be active when KVM #VMExit
>> handlers run. Up until the point which we architectully need to
>> access host (or other VM) sensitive data.
>>
>> This patch just create kvm_mm but never makes it active yet.
>> This will be done by next commits.
> 
> NAK to this whole pile of code.  KVM is not so special that it can
> duplicate core infrastructure like this.  Use copy_init_mm() or
> improve it as needed.
> 
> --Andy
> 

This was originally inspired from how efi_mm is built. If I remember
correctly copy_init_mm() or other mm init functions do initialization
we don't need in this case; we basically want a blank mm. I will have
another look at copy_init_mm().

In any case, if we really need a mm create/init function I agree it
doesn't below to kvm. For now, this part of shortcuts used for the POC.

alex.