From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E99CC4332F for ; Mon, 19 Dec 2022 14:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232479AbiLSOhV (ORCPT ); Mon, 19 Dec 2022 09:37:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232548AbiLSOgz (ORCPT ); Mon, 19 Dec 2022 09:36:55 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB46712090; Mon, 19 Dec 2022 06:36:34 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id ECC051EC06BD; Mon, 19 Dec 2022 15:36:32 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1671460593; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=Nr0Z4OvkPMBKiUgwrvy1b0JeJ5CuH4u8cdycIbF3VTo=; b=g4O8WnDjjWmrtbFmMTY4G0yltCqzIeXhWywY3xwLBgdFTN9TCYZMZhAq9By4cTHHjnVkHt 354idtEXaLQwUDtNstFC6rPiAS1iw8va+w5OrbtVNCuvMSntL0hbmQcddYbRIVl0pEcCkP SG+jpLF4Ne/7gzC4KSRDGyQn3EtYD1Q= Date: Mon, 19 Dec 2022 15:36:28 +0100 From: Borislav Petkov To: Chao Peng Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , tabba@google.com, Michael Roth , mhocko@suse.com, wei.w.wang@intel.com Subject: Re: [PATCH v10 3/9] KVM: Extend the memslot to support fd-based private memory Message-ID: References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> <20221202061347.1070246-4-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221202061347.1070246-4-chao.p.peng@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Dec 02, 2022 at 02:13:41PM +0800, Chao Peng wrote: > In memory encryption usage, guest memory may be encrypted with special > key and can be accessed only by the guest itself. We call such memory > private memory. It's valueless and sometimes can cause problem to allow valueless? I can't parse that. > userspace to access guest private memory. This new KVM memslot extension > allows guest private memory being provided through a restrictedmem > backed file descriptor(fd) and userspace is restricted to access the > bookmarked memory in the fd. bookmarked? > This new extension, indicated by the new flag KVM_MEM_PRIVATE, adds two > additional KVM memslot fields restricted_fd/restricted_offset to allow > userspace to instruct KVM to provide guest memory through restricted_fd. > 'guest_phys_addr' is mapped at the restricted_offset of restricted_fd > and the size is 'memory_size'. > > The extended memslot can still have the userspace_addr(hva). When use, a "When un use, ..." ... > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index a8e379a3afee..690cb21010e7 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -50,6 +50,8 @@ config KVM > select INTERVAL_TREE > select HAVE_KVM_PM_NOTIFIER if PM > select HAVE_KVM_MEMORY_ATTRIBUTES > + select HAVE_KVM_RESTRICTED_MEM if X86_64 > + select RESTRICTEDMEM if HAVE_KVM_RESTRICTED_MEM Those deps here look weird. RESTRICTEDMEM should be selected by TDX_GUEST as it can't live without it. Then you don't have to select HAVE_KVM_RESTRICTED_MEM simply because of X86_64 - you need that functionality when the respective guest support is enabled in KVM. Then, looking forward into your patchset, I'm not sure you even need HAVE_KVM_RESTRICTED_MEM - you could make it all depend on CONFIG_RESTRICTEDMEM. But that's KVM folks call - I'd always aim for less Kconfig items because we have waay too many. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette