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]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEC84C83030 for ; Mon, 7 Jul 2025 23:25:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 58C5C6B018C; Mon, 7 Jul 2025 19:25:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 53D666B018D; Mon, 7 Jul 2025 19:25:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 42C2F6B018F; Mon, 7 Jul 2025 19:25:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 2C4936B018C for ; Mon, 7 Jul 2025 19:25:19 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id E23381D912E for ; Mon, 7 Jul 2025 23:25:18 +0000 (UTC) X-FDA: 83639051916.19.6EB1401 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) by imf18.hostedemail.com (Postfix) with ESMTP id 1374F1C0004 for ; Mon, 7 Jul 2025 23:25:16 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=Cwx0NZzY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf18.hostedemail.com: domain of 3W1dsaAYKCAYykgtpimuumrk.iusrot03-ssq1giq.uxm@flex--seanjc.bounces.google.com designates 209.85.216.73 as permitted sender) smtp.mailfrom=3W1dsaAYKCAYykgtpimuumrk.iusrot03-ssq1giq.uxm@flex--seanjc.bounces.google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1751930717; a=rsa-sha256; cv=none; b=7OnD1F7rQ5yISc+95bzsKBLuumEokRuBuQhARXDcM1If+iLWMT+N/O2ohb0fBuPu+1waQH HfB+xh9A505kEgs9VQoSDcxzCzP2ahrridu/nsCRKFEqugfODFcQewXqmdNcqKiu5dZhyx si0CXS7oaKER6Gbfxun5w1utYbuWq0o= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=Cwx0NZzY; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf18.hostedemail.com: domain of 3W1dsaAYKCAYykgtpimuumrk.iusrot03-ssq1giq.uxm@flex--seanjc.bounces.google.com designates 209.85.216.73 as permitted sender) smtp.mailfrom=3W1dsaAYKCAYykgtpimuumrk.iusrot03-ssq1giq.uxm@flex--seanjc.bounces.google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1751930717; 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=JHbksS7Ik6LaoWpSJU26eNZHwnoWAXLMnPu9PY2UpqE=; b=QgUaGuchJI9ea7KIVfYxUU8NvwBgApWLSR4gwEvrSG77ECjO5TcqkFTULYVlI/E9s5KCe6 8fl5KH9OcAkdXbdHWVG/byKT62rX3/zhi7meOwt9uDJ1o16nlVD9J5Mb0m3shD+njuQ4FT /QEoMXydRFrN/F8QqVlVfDfpHwedEeQ= Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-3138e64b3f1so4811821a91.3 for ; Mon, 07 Jul 2025 16:25:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1751930716; x=1752535516; 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=JHbksS7Ik6LaoWpSJU26eNZHwnoWAXLMnPu9PY2UpqE=; b=Cwx0NZzYcDk6SRpkOEwuFKZDYUUkrkesZmFXP7y7sjTfS6004CwcXjii+6wkPD+4Xp VFVR6RtQpwe53tedBP5KHZRqbn98NjBWvSzCTpisr/fz5cAyuWTVB2uSFAmMgaL/ObTv VsgbJebh0JkS/lU4tGxJca6UjVb8Zj7Ew5xmnM/jNMgEsEEvlb1IDOiyl1TMZWG+TxAb otH+ECZ1fwAMPALWU6gLeCrPpVazNeYtkwvNBE/1wzsCwFfun+Omdm3tRtNx4mEiI34e fQ7tFCG0bkv5WWKYoJgsoHpiOZZNJdI2UTgN401AVbQz0xssuVF63jiBI4m/5kxmrVB7 bRMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751930716; x=1752535516; 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=JHbksS7Ik6LaoWpSJU26eNZHwnoWAXLMnPu9PY2UpqE=; b=jp1t16mGtrzl40CI3MDXhv3jEtog0Br931dwiH3HeFqjDbvTHvrc9BLaOPvlzmubx3 F4Jn5DQue6gpKDK7ZHQLkw27Cmmy9k2A6uvkJunDqNzv0Vj+/SOvyk0qWy5IpTasKMCi lHI9+wz5VLKpeOjsTbVMmuxTrNkAzPkmBej9K20Lan3S+xVpx4i+4mO+nPCjAkV+cc2c KMcZw8QR/6Svi3/UvvpVumhDc4Rr84Pj66nURtWzDoASl1zZSvkIUHySnJhJ2DlJgKSO uKJxXSWy6LFNjrB5Eb/8y7PXbI32DvYu3muyvWlU8shMwnydI3hh7u5cHLyaWPy0iyIP +/KQ== X-Forwarded-Encrypted: i=1; AJvYcCVJ8slUVHrG34QGxr7d2OrtpRJvjN2O6Rc9DYkPz8dKOMGsOnUYGr2vDwQR5wxEpUnAyb5f8xASIA==@kvack.org X-Gm-Message-State: AOJu0Yxp6FwA7EiFlOs7B2Fh7YEUV/UimGPCXQPjOcpV3jxtikxQNnWd /0hhsQhF+9vQbHUD2k1aAj8a7sZyTCfCSW5pOKlvHvIEuFu0j9taLm/TppmZrMyC7RV5Abqh0wJ 3miJ3hQ== X-Google-Smtp-Source: AGHT+IHec07vkrbcNzUBZe/F6EmhpBPtyl7Ef0BOzGMA51wQ8QB8Pn/cPlRz3g6O/7DZmfJqJVUpfLdRuGc= X-Received: from pjbqx14.prod.google.com ([2002:a17:90b:3e4e:b0:312:e914:4548]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:37c8:b0:311:ab20:159d with SMTP id 98e67ed59e1d1-31aadd9ce5bmr19229725a91.19.1751930715704; Mon, 07 Jul 2025 16:25:15 -0700 (PDT) Date: Mon, 7 Jul 2025 16:25:14 -0700 In-Reply-To: Mime-Version: 1.0 References: Message-ID: Subject: Re: [RFC PATCH v2 00/51] 1G page support for guest_memfd From: Sean Christopherson To: Vishal Annapurve Cc: Yan Zhao , Xiaoyao Li , Ackerley Tng , kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-fsdevel@vger.kernel.org, aik@amd.com, ajones@ventanamicro.com, akpm@linux-foundation.org, amoorthy@google.com, anthony.yznaga@oracle.com, anup@brainfault.org, aou@eecs.berkeley.edu, bfoster@redhat.com, binbin.wu@linux.intel.com, brauner@kernel.org, catalin.marinas@arm.com, chao.p.peng@intel.com, chenhuacai@kernel.org, dave.hansen@intel.com, david@redhat.com, dmatlack@google.com, dwmw@amazon.co.uk, erdemaktas@google.com, fan.du@intel.com, fvdl@google.com, graf@amazon.com, haibo1.xu@intel.com, hch@infradead.org, hughd@google.com, ira.weiny@intel.com, isaku.yamahata@intel.com, jack@suse.cz, james.morse@arm.com, jarkko@kernel.org, jgg@ziepe.ca, jgowans@amazon.com, jhubbard@nvidia.com, jroedel@suse.de, jthoughton@google.com, jun.miao@intel.com, kai.huang@intel.com, keirf@google.com, kent.overstreet@linux.dev, kirill.shutemov@intel.com, liam.merwick@oracle.com, maciej.wieczor-retman@intel.com, mail@maciej.szmigiero.name, maz@kernel.org, mic@digikod.net, michael.roth@amd.com, mpe@ellerman.id.au, muchun.song@linux.dev, nikunj@amd.com, nsaenz@amazon.es, oliver.upton@linux.dev, palmer@dabbelt.com, pankaj.gupta@amd.com, paul.walmsley@sifive.com, pbonzini@redhat.com, pdurrant@amazon.co.uk, peterx@redhat.com, pgonda@google.com, pvorel@suse.cz, qperret@google.com, quic_cvanscha@quicinc.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, quic_svaddagi@quicinc.com, quic_tsoni@quicinc.com, richard.weiyang@gmail.com, rick.p.edgecombe@intel.com, rientjes@google.com, roypat@amazon.co.uk, rppt@kernel.org, shuah@kernel.org, steven.price@arm.com, steven.sistare@oracle.com, suzuki.poulose@arm.com, tabba@google.com, thomas.lendacky@amd.com, usama.arif@bytedance.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, vkuznets@redhat.com, wei.w.wang@intel.com, will@kernel.org, willy@infradead.org, yilun.xu@intel.com, yuzenghui@huawei.com, zhiquan1.li@intel.com Content-Type: text/plain; charset="us-ascii" X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1374F1C0004 X-Stat-Signature: 67zu94zisjys3aofjztft4o5azr8qdpq X-Rspam-User: X-HE-Tag: 1751930716-158500 X-HE-Meta: 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 vlAHhYIZ 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 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: List-Subscribe: List-Unsubscribe: On Tue, Jul 01, 2025, Vishal Annapurve wrote: > I would be curious to understand if we need zeroing on conversion for > Confidential VMs. If not, then the simple rule of zeroing on > allocation only will work for all usecases. Unless I'm misunderstanding what your asking, pKVM very specific does NOT want zeroing on conversion, because one of its use cases is in-place conversion, e.g. to fill a shared buffer and then convert it to private so that the buffer can be processed in the TEE. Some architectures, e.g. SNP and TDX, may effectively require zeroing on conversion, but that's essentially a property of the architecture, i.e. an arch/vendor specific detail.