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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DBC40FF512F for ; Wed, 8 Apr 2026 00:31:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DAB1E6B0088; Tue, 7 Apr 2026 20:30:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D5BAC6B0089; Tue, 7 Apr 2026 20:30:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C4A8E6B008A; Tue, 7 Apr 2026 20:30:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id B38C26B0088 for ; Tue, 7 Apr 2026 20:30:59 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id E287BC2E24 for ; Wed, 8 Apr 2026 00:30:58 +0000 (UTC) X-FDA: 84633508596.06.A470947 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) by imf28.hostedemail.com (Postfix) with ESMTP id 398D4C000F for ; Wed, 8 Apr 2026 00:30:57 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=lVOPp7Z6; spf=pass (imf28.hostedemail.com: domain of 3v6HVaQYKCK4gSObXQUccUZS.QcaZWbil-aaYjOQY.cfU@flex--seanjc.bounces.google.com designates 209.85.210.202 as permitted sender) smtp.mailfrom=3v6HVaQYKCK4gSObXQUccUZS.QcaZWbil-aaYjOQY.cfU@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1775608257; a=rsa-sha256; cv=none; b=tHNJHpaLj+eatcnlTRiSrkfQkv+ip3oF+VjRdQYTa0+uTDrK5WtMmKGRvKovYGWGO8puns OTGG+t5OdjVyE2+WWO++ZGsq+bkMEYh/qatUqtJQZnmdgpilJrtF4ZL8M3Bt41D3gt7IHZ 6SawoTgZHhHy9W4g9hKXu2zOqorqYwc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1775608257; h=from:from:sender: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:dkim-signature; bh=yxNq84u8TlwsmIxTYoSXMB/rB8U2PkuGcR9W+hscQl8=; b=btC2LWz0PflHP0Yb9Yjfcg7lxFEzVkbXNqX63fRZT94SQEG0faEu0q9mknfWQz3yRaQ1NO 4GuncYzbk5Wwwi0fTopUZY264XCSnULrc1Oi7FYWQSlkZZJe6ESNjUcdjpdKLSb5uRqjqT IrQIXqfp+oNzQO0bgdO++NZbxtsm1eY= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=lVOPp7Z6; spf=pass (imf28.hostedemail.com: domain of 3v6HVaQYKCK4gSObXQUccUZS.QcaZWbil-aaYjOQY.cfU@flex--seanjc.bounces.google.com designates 209.85.210.202 as permitted sender) smtp.mailfrom=3v6HVaQYKCK4gSObXQUccUZS.QcaZWbil-aaYjOQY.cfU@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-82c83bd48afso3185112b3a.3 for ; Tue, 07 Apr 2026 17:30:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775608256; x=1776213056; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=yxNq84u8TlwsmIxTYoSXMB/rB8U2PkuGcR9W+hscQl8=; b=lVOPp7Z6djMgL2tOQ7u+avKhcHrgFArU48RQlKCrgjogA+x9zga7xB11mYcmFE6Cqo kqoHQIIOxSP2hp2vA8FRFalHgxIwWy5lQ8mUM3Css8qmT3dipegTjCJviC/intsAtmRn om7b8Vi6fzGO6GUn340xYFLnFnk53ZoIaZIH1LCHtcj8DcEI8klAR2TM/mve/1zM3yZ4 shH1nUsHeDxXEda8lmVaO78EbP0HY2ugrhQf9RAt56Wt2Hc5SIwFuzryvGRtBJGVARI5 Kt7ldg1eCul8UmIZGKKZdFq0ixspy2qynufSA35O9KgoDdeEtiHYxeboaF1kwDhA9uoD gCSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775608256; x=1776213056; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yxNq84u8TlwsmIxTYoSXMB/rB8U2PkuGcR9W+hscQl8=; b=DAaIGMtPRiQ4BrZU6ZmzKQkMHv3WAuG9wZp2JbGo4rkMdtCKLnlGqY1wKLR+F5fzqh fDJm2WX8PqQLL1a4z4+VW5LqeJ87oLTmxafJ2LfDKYDaj/6tnYzI9D/JNxxYEVzRbKSN PGUB5MorgfAqsMH73J6RQgVtEeIYZDXG4qcpx93+eJYywyjUH5dRrW1EpYIsm0eKzAR+ Wv3Iuorq+Wf047kiLaxdrYNiY6A2W2Jy4zfcXEIhrrOLX0W2GFZSGyXENdxjqEL18DlZ QXUiFFWLOPtAbd33rUmY3ibHvDFb12oIT/ecPNlPo0H8W327I7hffGseuF1q1gWY1nAf ZOGQ== X-Forwarded-Encrypted: i=1; AJvYcCXe3S3q/IJH3bdjsHVNsUTC7wxgiFVZBT9Til0uZz5EegbWK3n7Cm9K2UJvpmgDP7hgcn/mRLHLCw==@kvack.org X-Gm-Message-State: AOJu0YxZaNp0lEcbncigbxHdT9x40vHWMLlvxKJEe0CoGmr+DPRSnkMi WJrJUXItiVASd1QPwHyXnvzw8xuUQS+jYzY5Bs/SQ3zlmG2ebfxidZWyAY5mW7UElT8z0Lw7G51 iccNsGA== X-Received: from pfff14.prod.google.com ([2002:a05:6a00:bd0e:b0:829:7f86:623]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:348e:b0:827:28ba:ff00 with SMTP id d2e1a72fcca58-82d0da68e4amr19209230b3a.18.1775608255720; Tue, 07 Apr 2026 17:30:55 -0700 (PDT) Date: Tue, 7 Apr 2026 17:30:54 -0700 In-Reply-To: Mime-Version: 1.0 References: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> <20260326-gmem-inplace-conversion-v4-10-e202fe950ffd@google.com> <2r4mmfiuisw26qymahnbh2oxqkkrywqev477kc4rlkcyx7tels@c7ple7kdgpo3> Message-ID: Subject: Re: [PATCH RFC v4 10/44] KVM: guest_memfd: Add support for KVM_SET_MEMORY_ATTRIBUTES2 From: Sean Christopherson To: Ackerley Tng Cc: Michael Roth , aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, ira.weiny@intel.com, jmattson@google.com, jthoughton@google.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Jason Gunthorpe , Vlastimil Babka , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="us-ascii" X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 398D4C000F X-Stat-Signature: 8x8m7661jtrry35tibdi1ck8jufm8c5x X-HE-Tag: 1775608256-918506 X-HE-Meta: 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 XkRmWfqq j2XVRstHxzG8hiCsvL6eq01a8gIhPxF04Iw19QtpHbaxrN/LzZNxt2gbUao+Ti6/7EeSKp8XzuTGTinaQVh9/KHuO33sT8l6AHLGShhPcpmzb5cM/94KzoSCLDrbF7tB2MM6MYcRMjpFXK+N/HxybYIXTC9fBHz3uPvtM9KPdrFh9wOiCDXCen+r6TyGzbDRzYmzHNdhqw3iTOMA4S9Xnv+lmw0R9yzfM2j06DG6t58EVjGx2V3P9X84P94+9/pVinolok3e8KJAgTANIdQOMrENoujfsUnWLhMF1KQg4a5QSzFB6jABezC7oBqKPD817bGzU6O6wy+K8OkKVMCeJD34Al3B2yzX+59f7Srnei4ri6JcNqqGcLfCbHHKQ0/CB7lUyV+J8fubBber8EeAWqjAY+idp7TjiycDcf71vPj46mFs= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Apr 03, 2026, Ackerley Tng wrote: > Currently, in TDX's populate flow, KVM doesn't do any copying, it only > instructs TDX to do the copying. I disagree with this statement. For all intents and purposes, the TDX-Module is firmware. If Intel had elected to implement TDX via XuCode, and presented it to software as ISA (see SGX), then under the hood "firmware" would still be doing the actual copy, but KVM would be execute some form of "copy" instruction. Saying "KVM doesn't do any copying" is (very loosely) analogous to saying that KVM doesn't copy anything when it does REP MOVSQ. It wasn't me your honor, Intel's string engine did it! I don't think it changes anything in practice, but I don't want to treat TDX SEAMCALLs (or SNP PSP commands) as something completely different than what we usually think of as "hardware".