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 2BB2DC83F22 for ; Fri, 18 Jul 2025 02:57:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8F8BB8D0002; Thu, 17 Jul 2025 22:57:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8D7058D0001; Thu, 17 Jul 2025 22:57:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BF198D0002; Thu, 17 Jul 2025 22:57:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 6A54A8D0001 for ; Thu, 17 Jul 2025 22:57:12 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D57A0C0254 for ; Fri, 18 Jul 2025 02:57:11 +0000 (UTC) X-FDA: 83675873862.06.C321481 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) by imf20.hostedemail.com (Postfix) with ESMTP id 0D8711C000C for ; Fri, 18 Jul 2025 02:57:08 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=XdEM8qVG; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf20.hostedemail.com: domain of xiaoyao.li@intel.com designates 198.175.65.21 as permitted sender) smtp.mailfrom=xiaoyao.li@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1752807429; a=rsa-sha256; cv=none; b=RLU7W1a4oIS7+IqI1jw3UvcPscEBseWDJ19LApYm+Edwy7EhD5fSOuanvrgIM4ppkN3ju1 ZBZaXEAhAD7vVnTkd/evNzccV9TEyib9nu74SRolwYujQtXGQcj9FqPdilp0d79Vrln/Ci dicg4IUq0reavdA06YFMZWZo1UHjHhc= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=XdEM8qVG; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf20.hostedemail.com: domain of xiaoyao.li@intel.com designates 198.175.65.21 as permitted sender) smtp.mailfrom=xiaoyao.li@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1752807429; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=KJ/6LQb4mNwCkzXHP5KToREZjyKNR1k463y+aFkZ/0U=; b=Qg6Uksohp8fgpTNhVNTCJkio5cXvQDyE4PAuu3dCQRqZd70z9MjvswXghcBdkBNddsCnGT HAyXqAh1qPe+yyepaZe9PrEEIhJGkg4VrF7NUwXhQJ7nj6fWK6436SiqBw+Q/FWRGcT3R9 wAuwnBCIqrvqJRlJQeN8vGfbkJz0W0Y= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1752807429; x=1784343429; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=VNm2yIjyNR+4MfYbdw7jgNE502i3pDkkpT5hsJAXhcQ=; b=XdEM8qVGgKw4KsxxJ+sy/qhsyWERzPVvNQOMt0do0eK8qomRDu7aiY54 RmlpyAXTUOP4uXe2b5CxpBpdWjXV69UwWgUpBLct4B/McK3vDpxYaeY0f 5Pvwr4/4YSp65WEdubthfxRIn69HD5zZgTOW7QWJzn8J/RdN+cnFoPesK IOb1VvDFbWg90DeWYGaL9eiVqeVe31YWhjj8MvPgy6nXgDFXKculFTgE/ zpxBSzvVk49oHxiXK4lULdqn5pdaBEb9J14qdViuopudlFki7XUjyLjsa k01+EDVm1QH5tsU2P9A7ZsfAqIfktRBSMgpQFzLLdjvoaqkSbryjO03pN Q==; X-CSE-ConnectionGUID: j4umvZm9RIKy4fGxXRAiuQ== X-CSE-MsgGUID: KyX43labRt+tG8VsfKrtTw== X-IronPort-AV: E=McAfee;i="6800,10657,11495"; a="54977967" X-IronPort-AV: E=Sophos;i="6.16,320,1744095600"; d="scan'208";a="54977967" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2025 19:57:06 -0700 X-CSE-ConnectionGUID: 4aAcsyaETE28nvuGRlN+zw== X-CSE-MsgGUID: BbAsaMudTLW2zflXrSC6Ng== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,320,1744095600"; d="scan'208";a="157340783" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2025 19:56:52 -0700 Message-ID: Date: Fri, 18 Jul 2025 10:56:49 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v15 08/21] KVM: guest_memfd: Allow host to map guest_memfd pages To: Fuad Tabba , kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com References: <20250717162731.446579-1-tabba@google.com> <20250717162731.446579-9-tabba@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20250717162731.446579-9-tabba@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: wo99rgdum6i6pjhd35cog8cbjh9h3sr5 X-Rspam-User: X-Rspamd-Queue-Id: 0D8711C000C X-Rspamd-Server: rspam02 X-HE-Tag: 1752807428-827035 X-HE-Meta: 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 vm2LhBJt vBokELZWWSeNrShfht8wibK2SueRQirJ0FWqeqEU/Z/QHd6n93363RuSv98QOsOojeUlFkdUkgk3WxxU/ITqQ4aqSku79UKZMJzzZmy9kpVXyNV8qwPgumMmW0XIphqk+OlFCeU+Jgso3aSZwpHBCyd2Sv+MrLJWNI/f8CzhgDftigWlLop3rXjOoUo65Bng4DIHWbi0W9IT/l7PH1LY7J6/Z6X/PekIf8qV0EHvLNTGrjzBl7/gWGBiTybQor8TCtfomR8L/SBsRuiCqux3bCs9ET1Fq+VeDy2St7zcUw+KuYpWKwz5zJJlTWU3CgU/8BkE3+bocwJXlx2BWkgiQyhEEZozrKx0RDmLrWgTub2X+n2pxmRsMarNT7CdUsPk6pw7IjWUbrqR7A66HIOMaDF231Q== 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 7/18/2025 12:27 AM, Fuad Tabba wrote: > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 1ec71648824c..9ac21985f3b5 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -740,6 +740,19 @@ static inline bool kvm_arch_supports_gmem(struct kvm *kvm) > } > #endif > > +/* > + * Returns true if this VM supports mmap() in guest_memfd. > + * > + * Arch code must define kvm_arch_supports_gmem_mmap if support for guest_memfd > + * is enabled. > + */ > +#if !defined(kvm_arch_supports_gmem_mmap) Unless being given a reason or you change it to #if !defined(kvm_arch_supports_gmem_mmap) && !IS_ENABLED(CONFIG_KVM_GMEM) I will repeat my opinion as what on v14[*] * It describes the similar requirement as kvm_arch_has_private_mem and * kvm_arch_supports_gmem, but it doesn't have the check of * * && !IS_ENABLED(CONFIG_KVM_GMEM) * * So it's straightforward for people to wonder why. * * I would suggest just adding the check of !IS_ENABLED(CONFIG_KVM_GMEM) * like what for kvm_arch_has_private_mem and kvm_arch_supports_gmem. * So it will get compilation error if any ARCH enables CONFIG_KVM_GMEM * without defining kvm_arch_supports_gmem_mmap. [*] https://lore.kernel.org/all/e1470c54-fe2b-4fdf-9b4b-ce9ef0d04a1b@intel.com/ > +static inline bool kvm_arch_supports_gmem_mmap(struct kvm *kvm) > +{ > + return false; > +} > +#endif > +