From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Date: Thu, 20 Jul 2023 08:14:47 -0700 Subject: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory In-Reply-To: <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Message-ID: List-Id: To: kvm-riscv@lists.infradead.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Jul 20, 2023, Xiaoyao Li wrote: > On 7/19/2023 7:44 AM, Sean Christopherson wrote: > > @@ -5134,6 +5167,16 @@ static long kvm_vm_ioctl(struct file *filp, > > case KVM_GET_STATS_FD: > > r = kvm_vm_ioctl_get_stats_fd(kvm); > > break; > > + case KVM_CREATE_GUEST_MEMFD: { > > + struct kvm_create_guest_memfd guest_memfd; > > + > > + r = -EFAULT; > > + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) > > + goto out; > > + > > + r = kvm_gmem_create(kvm, &guest_memfd); > > + break; > > + } > > Does it need a new CAP to indicate the support of guest_memfd? Yeah, I meant to add that to the TODO list and forgot (obviously). > This is patch series introduces 3 new CAPs and it seems any one of them can > serve as the indicator of guest_memfd. > > +#define KVM_CAP_USER_MEMORY2 230 > +#define KVM_CAP_MEMORY_ATTRIBUTES 231 > +#define KVM_CAP_VM_TYPES 232 The number of new caps being added is the main why I didn't just add another one. On the other hand, we have room for a few billion caps, so one more isn't a big deal. So yeah, KVM_CAP_GUEST_MEMFD is probably the way to go. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6EC8718B07 for ; Thu, 20 Jul 2023 15:14:50 +0000 (UTC) Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-cf4cb742715so776290276.2 for ; Thu, 20 Jul 2023 08:14:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689866089; x=1690470889; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=zTnr2gXYIfqrhSL0WP50qLuqh3ZSH0gfVOnKmqwBvWYCge11/urc6Mcz48DQC5VeI6 s/bgjrFlzBMXd0PxaHBdxoR2ZqKrVqjnkCnhcQbbSnTvJYQ3aBe8wGkYdi1iCIBydfGh kDBro1Ztm9Xs7cfFTvZ7Ey8Gxe05PCCIDn4nx9L+2nwHbFPbro9d3jap/zFGaLY9lF26 GO0Vu5OUt+nUmBQOwJoSD8n40MC7ZQXlXpaj59Y1nIZxZy5/TzmEdTKZZXkcpmTSKYdO Y0fmzsgj8zCYsvUdMgpPWIv3Ur8RBp8NDUrrxEURomdLy8NcckIjCEtpSXTS4KS2mzFS 29+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689866089; x=1690470889; 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=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=Vj4CBtsZ/EVBbDNkrO2WOwgVjTWxwJ/lmeZWg3FrCVC2JRBmKie/UtHeKN1Nz6XGw/ BuLDWrUKBCmHIxXfdLk6qt9Dqzg2dvKOy+70lRsbUino1D1ovg9nHXR7jUHW8DceFy6+ i/dEkRfCHnPIVZsAZAMHkGioYi6kgTXkv7mcS6gVScaaV6wp12DsaGk+Av1W/FERSwji Mq2xyT95mp+fLM3hCvKuCcpEpynCj+qLK+yiW9qMm8HbDb9kRnnReAUZhDnRh6AMnWnc Pen+bicGwCmUp7u5eZa4GRUyVQu9LDMZMRqdxHmgkgt+6lRZaXhc2PITWyCMWcM5spEp 3MHw== X-Gm-Message-State: ABy/qLbXOAjcQw4m+4F9XpTzDuZyYgoKeFFq3XJHcYQucOGOmYIIVxLp 5DpwDp8oJSmZx0SMNj5t8pBZC4tWUXw= X-Google-Smtp-Source: APBJJlHgB47FmXfk0Rt+Hyu6ZgRaD/aSiXUWbAQerG5WzFKE3pY5cKaePpzhb9OPvUF/5F0XHeWF4GbW2oc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:a105:0:b0:c65:8983:ac2 with SMTP id z5-20020a25a105000000b00c6589830ac2mr17912ybh.5.1689866089303; Thu, 20 Jul 2023 08:14:49 -0700 (PDT) Date: Thu, 20 Jul 2023 08:14:47 -0700 In-Reply-To: <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Xiaoyao Li Cc: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Content-Type: text/plain; charset="us-ascii" On Thu, Jul 20, 2023, Xiaoyao Li wrote: > On 7/19/2023 7:44 AM, Sean Christopherson wrote: > > @@ -5134,6 +5167,16 @@ static long kvm_vm_ioctl(struct file *filp, > > case KVM_GET_STATS_FD: > > r = kvm_vm_ioctl_get_stats_fd(kvm); > > break; > > + case KVM_CREATE_GUEST_MEMFD: { > > + struct kvm_create_guest_memfd guest_memfd; > > + > > + r = -EFAULT; > > + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) > > + goto out; > > + > > + r = kvm_gmem_create(kvm, &guest_memfd); > > + break; > > + } > > Does it need a new CAP to indicate the support of guest_memfd? Yeah, I meant to add that to the TODO list and forgot (obviously). > This is patch series introduces 3 new CAPs and it seems any one of them can > serve as the indicator of guest_memfd. > > +#define KVM_CAP_USER_MEMORY2 230 > +#define KVM_CAP_MEMORY_ATTRIBUTES 231 > +#define KVM_CAP_VM_TYPES 232 The number of new caps being added is the main why I didn't just add another one. On the other hand, we have room for a few billion caps, so one more isn't a big deal. So yeah, KVM_CAP_GUEST_MEMFD is probably the way to go. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AA780EB64DA for ; Thu, 20 Jul 2023 15:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=kUPrlnRIjD6sAMipzHdibeksucBCYhTIrydtohu77dA=; b=N8UJe1wYP2ZynLFaiiMiqIW74N RhErB+aUfYPvO/pPCCiAdDOYcawFOpz3a4HXQjpmrFgKEuGPqLB9g3RduW39kVuqOsrZ6m6EvMz7r NCKAd90V+b8ghw59wtdlCxbGeIOKMM13a914oUDFOY3Ikea3VK3oJHRvYqix6dtKhR8C7y1XhF38V J/Y765q+cEUJKWV4HysUaOkgEPZZtWv1Bjb3ei0BQjKDzSqWcVtGoIqgCGsotV4SnzXmjOu9VW3R6 xZSdmGCHCZAqZyn5eIq5EMhPgQwctgtA2julJGdJ5YqTy8Ii8V4IoeNRd1aVqQCXiwPWM2NQcUSb1 BM/txr3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qMVMk-00BVtU-0f; Thu, 20 Jul 2023 15:14:54 +0000 Received: from mail-yb1-xb49.google.com ([2607:f8b0:4864:20::b49]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qMVMh-00BVrs-1w for linux-riscv@lists.infradead.org; Thu, 20 Jul 2023 15:14:52 +0000 Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-c0f35579901so791794276.0 for ; Thu, 20 Jul 2023 08:14:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689866089; x=1690470889; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=zTnr2gXYIfqrhSL0WP50qLuqh3ZSH0gfVOnKmqwBvWYCge11/urc6Mcz48DQC5VeI6 s/bgjrFlzBMXd0PxaHBdxoR2ZqKrVqjnkCnhcQbbSnTvJYQ3aBe8wGkYdi1iCIBydfGh kDBro1Ztm9Xs7cfFTvZ7Ey8Gxe05PCCIDn4nx9L+2nwHbFPbro9d3jap/zFGaLY9lF26 GO0Vu5OUt+nUmBQOwJoSD8n40MC7ZQXlXpaj59Y1nIZxZy5/TzmEdTKZZXkcpmTSKYdO Y0fmzsgj8zCYsvUdMgpPWIv3Ur8RBp8NDUrrxEURomdLy8NcckIjCEtpSXTS4KS2mzFS 29+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689866089; x=1690470889; 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=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=byBy+UdEPFbg4BkcrTbAZC4nMBq1ieDsxoU4M/sphIkXCtsEa53liEjJQgUYyM6ozG PMbKJJ6mafKgFZmoxZ9pYLaL5NKN6qRRrHwhMl7YdNrntcz3EfhHZHW4OLgCqA/R25X4 SGs3Nby47QZAgtY7YZsw+gi0xwZqUL0FOi8mc1IKHUBq9VdbA/jqw80G+tq9CI8FDdHH X/6wLNhNn/lE1cAL63Mvog2kG3RtH7Sa+a3f+wDvPaSmxZ3EugUuWwZlUMk+Fut5wUVD I+zi74g+55jqO5QuED3K2WihEkgyNqDKWalaBjAWQe2OlsMj6u540D2yNWAYSjWBlCZS qvyA== X-Gm-Message-State: ABy/qLbl8i1/0R67lYNc3ZLBjKSYSRkOzGhSUhMInfc4jEto5euywRkD FSLcHMZzsiiS9u7WU707FsqWOb1sXCw= X-Google-Smtp-Source: APBJJlHgB47FmXfk0Rt+Hyu6ZgRaD/aSiXUWbAQerG5WzFKE3pY5cKaePpzhb9OPvUF/5F0XHeWF4GbW2oc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:a105:0:b0:c65:8983:ac2 with SMTP id z5-20020a25a105000000b00c6589830ac2mr17912ybh.5.1689866089303; Thu, 20 Jul 2023 08:14:49 -0700 (PDT) Date: Thu, 20 Jul 2023 08:14:47 -0700 In-Reply-To: <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Xiaoyao Li Cc: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230720_081451_643206_BC04A368 X-CRM114-Status: GOOD ( 13.88 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Thu, Jul 20, 2023, Xiaoyao Li wrote: > On 7/19/2023 7:44 AM, Sean Christopherson wrote: > > @@ -5134,6 +5167,16 @@ static long kvm_vm_ioctl(struct file *filp, > > case KVM_GET_STATS_FD: > > r = kvm_vm_ioctl_get_stats_fd(kvm); > > break; > > + case KVM_CREATE_GUEST_MEMFD: { > > + struct kvm_create_guest_memfd guest_memfd; > > + > > + r = -EFAULT; > > + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) > > + goto out; > > + > > + r = kvm_gmem_create(kvm, &guest_memfd); > > + break; > > + } > > Does it need a new CAP to indicate the support of guest_memfd? Yeah, I meant to add that to the TODO list and forgot (obviously). > This is patch series introduces 3 new CAPs and it seems any one of them can > serve as the indicator of guest_memfd. > > +#define KVM_CAP_USER_MEMORY2 230 > +#define KVM_CAP_MEMORY_ATTRIBUTES 231 > +#define KVM_CAP_VM_TYPES 232 The number of new caps being added is the main why I didn't just add another one. On the other hand, we have room for a few billion caps, so one more isn't a big deal. So yeah, KVM_CAP_GUEST_MEMFD is probably the way to go. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 89066EB64DA for ; Thu, 20 Jul 2023 15:15:53 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20221208 header.b=zTnr2gXY; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4R6GTz62lXz3cBW for ; Fri, 21 Jul 2023 01:15:51 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20221208 header.b=zTnr2gXY; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=flex--seanjc.bounces.google.com (client-ip=2607:f8b0:4864:20::b49; helo=mail-yb1-xb49.google.com; envelope-from=3au-5zaykdboi40d926ee6b4.2ecb8dknff2-34lb8iji.epb01i.eh6@flex--seanjc.bounces.google.com; receiver=lists.ozlabs.org) Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4R6GSx2wj0z30Q4 for ; Fri, 21 Jul 2023 01:14:55 +1000 (AEST) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-c0f35579901so791795276.0 for ; Thu, 20 Jul 2023 08:14:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689866089; x=1690470889; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=zTnr2gXYIfqrhSL0WP50qLuqh3ZSH0gfVOnKmqwBvWYCge11/urc6Mcz48DQC5VeI6 s/bgjrFlzBMXd0PxaHBdxoR2ZqKrVqjnkCnhcQbbSnTvJYQ3aBe8wGkYdi1iCIBydfGh kDBro1Ztm9Xs7cfFTvZ7Ey8Gxe05PCCIDn4nx9L+2nwHbFPbro9d3jap/zFGaLY9lF26 GO0Vu5OUt+nUmBQOwJoSD8n40MC7ZQXlXpaj59Y1nIZxZy5/TzmEdTKZZXkcpmTSKYdO Y0fmzsgj8zCYsvUdMgpPWIv3Ur8RBp8NDUrrxEURomdLy8NcckIjCEtpSXTS4KS2mzFS 29+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689866089; x=1690470889; 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=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=QSygwMYTjVA93ExJ2oNL3gccQya5pJrVwX9aV98fi3lccHQYPCKRAUYfk/Sft0DXX6 RhVo7glblR37Q0siIB4fQxanGXftXNb9nU1OBwbEvzwNR7vMB7Wz20w3jQk4aMyRlNSR LIWkyhQCr/70E4fe79DwV45oHUKsp1BTwOyiXmUotIdqIv7406QoKawc0NqgVkANI8Ov AA5x27wjRLoNhkf/NEm6YQNXliTmbkh8DLb0QxjoL83OEuQawVxtrbqMO961Joik1pe7 LjRKPAcb4KbvdYiEJuYREAXGth/ANh77R1DUvD7ltEE/heuMa67J4qLc1u9nCXyi5K4i SDFQ== X-Gm-Message-State: ABy/qLbM2iIT+KpNQG5bGS05kw2s2Urrrr9LLQmL+0825y73wWjtuc5r bJTwxtddwbZPzDswdR3votO5s140SgM= X-Google-Smtp-Source: APBJJlHgB47FmXfk0Rt+Hyu6ZgRaD/aSiXUWbAQerG5WzFKE3pY5cKaePpzhb9OPvUF/5F0XHeWF4GbW2oc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:a105:0:b0:c65:8983:ac2 with SMTP id z5-20020a25a105000000b00c6589830ac2mr17912ybh.5.1689866089303; Thu, 20 Jul 2023 08:14:49 -0700 (PDT) Date: Thu, 20 Jul 2023 08:14:47 -0700 In-Reply-To: <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Xiaoyao Li Content-Type: text/plain; charset="us-ascii" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, David Hildenbrand , Yu Zhang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Chao Peng , linux-riscv@lists.infradead.org, Isaku Yamahata , Paul Moore , Marc Zyngier , Huacai Chen , James Morris , "Matthew Wilcox \(Oracle\)" , Wang , Fuad Tabba , Jarkko Sakkinen , "Serge E. Hallyn" , Maciej Szmigiero , Albert Ou , Vlastimil Babka , Michael Roth , Ackerley Tng , Paul Walmsley , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Quentin Perret , Liam Merwick , linux-mips@vger.kernel.org, Oliver Upton , linux-security-module@vger.kernel.org, Palmer Dabbelt , kvm-riscv@lists.infradead.org, Anup Patel , linux-fsdevel@vger.kernel.org, Paolo Bonzini , Andrew Morton , Vishal Annapurve , linuxppc-dev@lists.ozlabs.org, "Kirill A . Shutemov" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jul 20, 2023, Xiaoyao Li wrote: > On 7/19/2023 7:44 AM, Sean Christopherson wrote: > > @@ -5134,6 +5167,16 @@ static long kvm_vm_ioctl(struct file *filp, > > case KVM_GET_STATS_FD: > > r = kvm_vm_ioctl_get_stats_fd(kvm); > > break; > > + case KVM_CREATE_GUEST_MEMFD: { > > + struct kvm_create_guest_memfd guest_memfd; > > + > > + r = -EFAULT; > > + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) > > + goto out; > > + > > + r = kvm_gmem_create(kvm, &guest_memfd); > > + break; > > + } > > Does it need a new CAP to indicate the support of guest_memfd? Yeah, I meant to add that to the TODO list and forgot (obviously). > This is patch series introduces 3 new CAPs and it seems any one of them can > serve as the indicator of guest_memfd. > > +#define KVM_CAP_USER_MEMORY2 230 > +#define KVM_CAP_MEMORY_ATTRIBUTES 231 > +#define KVM_CAP_VM_TYPES 232 The number of new caps being added is the main why I didn't just add another one. On the other hand, we have room for a few billion caps, so one more isn't a big deal. So yeah, KVM_CAP_GUEST_MEMFD is probably the way to go. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 40427EB64DA for ; Thu, 20 Jul 2023 15:15:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=8yc0YywdW6TohwRDwA3ZmXZJPw3WbUH/KIdQ7Et0Yrk=; b=tbSACn8vlCkKfpgi+tD20Of0Pl cFAJf9VLpc5hHDa2cvhCXcr4UApjzFbGbNs2P6zt1vZLNl+qmJ2h08PK2PFZFObl8cZy9dBKIc0Gm AZTLW3cvZ43uElG0KCqoJJJi1m9S7Yc/Bcht7jdTOJXQ84SHZJ8m6l+ZPvtqPHE7BqPbOtBYELe3S ha4aoCKfxF+lrFIFOEbpAqkcSbzNeyVOh+OpPtJuQcUCgfGWOZtLzDZs59KstPziNjUZB0cEGDkfR A2QrcNdS7sjrO3fUZP83SlU1EzENP0771YjVRFA0UAdcz12M5bwKTle3M9s2pAjLGXQxfxpmiMTC5 mY1ETovw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qMVMk-00BVu1-2i; Thu, 20 Jul 2023 15:14:54 +0000 Received: from mail-yb1-xb4a.google.com ([2607:f8b0:4864:20::b4a]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qMVMh-00BVrt-23 for linux-arm-kernel@lists.infradead.org; Thu, 20 Jul 2023 15:14:52 +0000 Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-cf4cb742715so776287276.2 for ; Thu, 20 Jul 2023 08:14:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689866089; x=1690470889; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=zTnr2gXYIfqrhSL0WP50qLuqh3ZSH0gfVOnKmqwBvWYCge11/urc6Mcz48DQC5VeI6 s/bgjrFlzBMXd0PxaHBdxoR2ZqKrVqjnkCnhcQbbSnTvJYQ3aBe8wGkYdi1iCIBydfGh kDBro1Ztm9Xs7cfFTvZ7Ey8Gxe05PCCIDn4nx9L+2nwHbFPbro9d3jap/zFGaLY9lF26 GO0Vu5OUt+nUmBQOwJoSD8n40MC7ZQXlXpaj59Y1nIZxZy5/TzmEdTKZZXkcpmTSKYdO Y0fmzsgj8zCYsvUdMgpPWIv3Ur8RBp8NDUrrxEURomdLy8NcckIjCEtpSXTS4KS2mzFS 29+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689866089; x=1690470889; 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=jyO/GZcznauRS+IxFjefkQ411ageTxV8Pq4vykaVGvo=; b=l6ez03AAhgq7PKM/BW7sezVc+RLrHi0VwnydnjXYr9W/70ygxddtv5avWQQRpK7qvf dsQg9kFFfKF9/1Rd86+PoiT6BXJ5K0sn+PxzURxuzBqVCo8yHIxgvM8sEyD/RVDUliYX xUkZh8ja6pnnoSt/sXGXSivQGPL5413eSATG99bHB8q14pZdoAKAviiK+1mPIPEfg3yl 3MpNN99euwrHIbG4k0bn44zwZfbgppkHXFEdZLpN7rgUUvbanW9+mcq3jrqSIWlVjrff Bl5cxDa5rPYL91vN/2R1Tw/CcZklkSY19Y1OnGzw56+bmY+TQ6xY2oDGsrcu/PHE9QNZ U+pQ== X-Gm-Message-State: ABy/qLY4Dbid9xJfRgFJzg2htu7kYKIj3PM4xpomfSSVZPcFG4zjV+xx q3I2i5YMhnvyXZasCtE6qWPVelx1aPA= X-Google-Smtp-Source: APBJJlHgB47FmXfk0Rt+Hyu6ZgRaD/aSiXUWbAQerG5WzFKE3pY5cKaePpzhb9OPvUF/5F0XHeWF4GbW2oc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:a105:0:b0:c65:8983:ac2 with SMTP id z5-20020a25a105000000b00c6589830ac2mr17912ybh.5.1689866089303; Thu, 20 Jul 2023 08:14:49 -0700 (PDT) Date: Thu, 20 Jul 2023 08:14:47 -0700 In-Reply-To: <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <83eb5c50-7287-7845-ffc3-a7c58e638ea5@intel.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Xiaoyao Li Cc: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230720_081451_673090_0EF8C8A4 X-CRM114-Status: GOOD ( 15.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 20, 2023, Xiaoyao Li wrote: > On 7/19/2023 7:44 AM, Sean Christopherson wrote: > > @@ -5134,6 +5167,16 @@ static long kvm_vm_ioctl(struct file *filp, > > case KVM_GET_STATS_FD: > > r = kvm_vm_ioctl_get_stats_fd(kvm); > > break; > > + case KVM_CREATE_GUEST_MEMFD: { > > + struct kvm_create_guest_memfd guest_memfd; > > + > > + r = -EFAULT; > > + if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd))) > > + goto out; > > + > > + r = kvm_gmem_create(kvm, &guest_memfd); > > + break; > > + } > > Does it need a new CAP to indicate the support of guest_memfd? Yeah, I meant to add that to the TODO list and forgot (obviously). > This is patch series introduces 3 new CAPs and it seems any one of them can > serve as the indicator of guest_memfd. > > +#define KVM_CAP_USER_MEMORY2 230 > +#define KVM_CAP_MEMORY_ATTRIBUTES 231 > +#define KVM_CAP_VM_TYPES 232 The number of new caps being added is the main why I didn't just add another one. On the other hand, we have room for a few billion caps, so one more isn't a big deal. So yeah, KVM_CAP_GUEST_MEMFD is probably the way to go. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel