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Date:   Tue, 20 Oct 2020 09:12:17 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Kirill A. Shutemov" <kirill@shutemov.name>
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        David Rientjes <rientjes@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Will Drewry <wad@chromium.org>,
        "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
        "Kleen, Andi" <andi.kleen@intel.com>,
        Liran Alon <liran.alon@oracle.com>,
        Mike Rapoport <rppt@kernel.org>, x86@kernel.org,
        kvm@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFCv2 15/16] KVM: Unmap protected pages from direct mapping
Message-ID: <20201020071217.GU2611@hirez.programming.kicks-ass.net>
References: <20201020061859.18385-1-kirill.shutemov@linux.intel.com>
 <20201020061859.18385-16-kirill.shutemov@linux.intel.com>
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In-Reply-To: <20201020061859.18385-16-kirill.shutemov@linux.intel.com>
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On Tue, Oct 20, 2020 at 09:18:58AM +0300, Kirill A. Shutemov wrote:
> If the protected memory feature enabled, unmap guest memory from
> kernel's direct mappings.
> 
> Migration and KSM is disabled for protected memory as it would require a
> special treatment.

How isn't disabling migration a problem? Are we going to back allocation
by CMA instead?