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Shutemov" , Vitaly Kuznetsov Cc: David Rientjes , Andrea Arcangeli , Kees Cook , Will Drewry , "Edgecombe, Rick P" , "Kleen, Andi" , x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel References: <20200522125214.31348-1-kirill.shutemov@linux.intel.com> <20200522125214.31348-7-kirill.shutemov@linux.intel.com> <87a71w832c.fsf@vitty.brq.redhat.com> <20200525151755.yzbmemtrii455s6k@box> From: Paolo Bonzini Message-ID: Date: Mon, 1 Jun 2020 18:35:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200525151755.yzbmemtrii455s6k@box> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 9B03F18086E2B X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 25/05/20 17:17, Kirill A. Shutemov wrote: >> Personally, I would've just added 'struct kvm' pointer to 'struct >> kvm_memory_slot' to be able to extract 'mem_protected' info when >> needed. This will make the patch much smaller. > Okay, can do. > > Other thing I tried is to have per-slot flag to indicate that it's > protected. But Sean pointed that it's all-or-nothing feature and having > the flag in the slot would be misleading. > Perhaps it would be misleading, but it's an optimization. Saving a pointer dereference can be worth it, also because there are some places where we just pass around a memslot and we don't have the struct kvm*. Also, it's an all-or-nothing feature _now_. It doesn't have to remain that way. Paolo