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(p200300cbc708fe008ba45871abc38a75.dip0.t-ipconnect.de. [2003:cb:c708:fe00:8ba4:5871:abc3:8a75]) by smtp.gmail.com with ESMTPSA id v11-20020adfe4cb000000b0021e6b62fde2sm10429441wrm.59.2022.07.26.07.30.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Jul 2022 07:30:57 -0700 (PDT) Message-ID: Date: Tue, 26 Jul 2022 16:30:55 +0200 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCHv7 02/14] mm: Add support for unaccepted memory To: Borislav Petkov Cc: Dave Hansen , "Kirill A. Shutemov" , Andy Lutomirski , Sean Christopherson , Andrew Morton , Joerg Roedel , Ard Biesheuvel , Andi Kleen , Kuppuswamy Sathyanarayanan , David Rientjes , Vlastimil Babka , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Paolo Bonzini , Ingo Molnar , Varad Gautam , Dario Faggioli , Mike Rapoport , marcelo.cerri@canonical.com, tim.gardner@canonical.com, khalid.elmously@canonical.com, philip.cox@canonical.com, x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Mike Rapoport References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com> <20220614120231.48165-3-kirill.shutemov@linux.intel.com> <707ca113-c2a2-8fe2-a22c-5be13adc7bb4@intel.com> <7d664831-a78c-4a4f-5bd6-f0e04463ca7c@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 25.07.22 14:53, Borislav Petkov wrote: > On Mon, Jul 25, 2022 at 02:38:57PM +0200, David Hildenbrand wrote: >> The less core-MM code to handle unaccepted memory the better. Meaning, >> that any kind of additional pre-acceptance (in addition to what we have >> here) needs good justification. > > I actually mean to have a user interface to have the core code > pre-accept. I.e., interface to what will be already there anyway. > Ah, got it. The "issue" with ordinary prefaulting in user space is that you'll also end up zeroing the memory. But yeah, it should just accept a bunch of memory. > Or is that frowned upon too? I was assuming you'd want some additional interface that only accept memory without actually temporarily allocating it. -- Thanks, David / dhildenb