From nobody Mon Feb 9 04:46:12 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linux.intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1640100434881600.8143420634691; Tue, 21 Dec 2021 07:27:14 -0800 (PST) Received: from localhost ([::1]:42248 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mzh2n-000357-SK for importer@patchew.org; Tue, 21 Dec 2021 10:27:13 -0500 Received: from eggs.gnu.org ([209.51.188.92]:46454) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mzgq7-0001Iy-Kj for qemu-devel@nongnu.org; Tue, 21 Dec 2021 10:14:07 -0500 Received: from mga11.intel.com ([192.55.52.93]:41795) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mzgq5-0008Qo-TC for qemu-devel@nongnu.org; Tue, 21 Dec 2021 10:14:07 -0500 Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Dec 2021 07:14:04 -0800 Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga005.jf.intel.com with ESMTP; 21 Dec 2021 07:13:56 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640099645; x=1671635645; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=We7gK/h+jEknZOV42LJTALD74jcdTiL5CfglrMRHFxI=; b=ZyhsokvGHo9XCsNX7JMF7y7+yP2PNu4BI135IcezbXRqYw+Xr2VkBli5 i0VDXQlZMKnDoQs/QOYB9Q7+SGIGlil0WLPa31gRHsyKcoayNjHabS984 K3dLdx4nhfMfrzkAo29kOi+/pKIEOQ54V1nR9/GXrTvzSJDE4Myzo96mn booPECQ/WUEtVBw/1yICqqr2rjZaESoJVh6eUk6w+2ojzPUGCLz6xoAWM +3BBUY8VeDJTqojkh6Cg+D2CgeOgHXpozTUcGCzpa1C/aE9T2gtRFSJfI vjBwdYC+B8YdmFICBNyu67B+Pz1kzurwseiCwuGXFcFSzNOmskjIanCam g==; X-IronPort-AV: E=McAfee;i="6200,9189,10204"; a="237946939" X-IronPort-AV: E=Sophos;i="5.88,223,1635231600"; d="scan'208";a="237946939" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,223,1635231600"; d="scan'208";a="684688711" From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org Subject: [PATCH v3 15/15] KVM: Register/unregister private memory slot to memfd Date: Tue, 21 Dec 2021 23:11:25 +0800 Message-Id: <20211221151125.19446-16-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211221151125.19446-1-chao.p.peng@linux.intel.com> References: <20211221151125.19446-1-chao.p.peng@linux.intel.com> Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=192.55.52.93; envelope-from=chao.p.peng@linux.intel.com; helo=mga11.intel.com X-Spam_score_int: -71 X-Spam_score: -7.2 X-Spam_bar: ------- X-Spam_report: (-7.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.203, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , jun.nakajima@intel.com, david@redhat.com, "J . Bruce Fields" , dave.hansen@intel.com, "H . Peter Anvin" , Chao Peng , ak@linux.intel.com, Jonathan Corbet , Joerg Roedel , x86@kernel.org, Hugh Dickins , Ingo Molnar , Borislav Petkov , luto@kernel.org, Thomas Gleixner , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , susie.li@intel.com, Jeff Layton , john.ji@intel.com, Yu Zhang , Paolo Bonzini , Andrew Morton , "Kirill A . Shutemov" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1640100436334100001 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Expose KVM_MEM_PRIVATE flag and register/unregister private memory slot to memfd when userspace sets the flag. KVM_MEM_PRIVATE is disallowed by default but architecture code can turn it on by implementing kvm_arch_private_memory_supported(). Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 35 +++++++++++++++++++++++++++++++---- 2 files changed, 33 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 0c53df0a6b2e..0f0e24f19892 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1096,6 +1096,8 @@ int kvm_arch_post_init_vm(struct kvm *kvm); void kvm_arch_pre_destroy_vm(struct kvm *kvm); int kvm_arch_create_vm_debugfs(struct kvm *kvm); bool kvm_arch_dirty_log_supported(struct kvm *kvm); +bool kvm_arch_private_memory_supported(struct kvm *kvm); + =20 #ifndef __KVM_HAVE_ARCH_VM_ALLOC /* diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 79313c549fb9..6eb0d86abdcf 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1509,6 +1509,11 @@ bool __weak kvm_arch_dirty_log_supported(struct kvm = *kvm) return true; } =20 +bool __weak kvm_arch_private_memory_supported(struct kvm *kvm) +{ + return false; +} + static int check_memory_region_flags(struct kvm *kvm, const struct kvm_userspace_memory_region_ext *mem) { @@ -1517,6 +1522,9 @@ static int check_memory_region_flags(struct kvm *kvm, if (kvm_arch_dirty_log_supported(kvm)) valid_flags |=3D KVM_MEM_LOG_DIRTY_PAGES; =20 + if (kvm_arch_private_memory_supported(kvm)) + valid_flags |=3D KVM_MEM_PRIVATE; + #ifdef __KVM_HAVE_READONLY_MEM valid_flags |=3D KVM_MEM_READONLY; #endif @@ -1708,9 +1716,21 @@ static int kvm_set_memslot(struct kvm *kvm, /* Copy the arch-specific data, again after (re)acquiring slots_arch_lock= . */ memcpy(&new->arch, &old.arch, sizeof(old.arch)); =20 + if (mem->flags & KVM_MEM_PRIVATE && change =3D=3D KVM_MR_CREATE) { + r =3D kvm_memfd_register(kvm, mem, new); + if (r) + goto out_slots; + } + r =3D kvm_arch_prepare_memory_region(kvm, new, mem, change); - if (r) + if (r) { + if (mem->flags & KVM_MEM_PRIVATE && change =3D=3D KVM_MR_CREATE) + kvm_memfd_unregister(kvm, new); goto out_slots; + } + + if (mem->flags & KVM_MEM_PRIVATE && change =3D=3D KVM_MR_DELETE) + kvm_memfd_unregister(kvm, new); =20 update_memslots(slots, new, change); slots =3D install_new_memslots(kvm, as_id, slots); @@ -1786,10 +1806,12 @@ int __kvm_set_memory_region(struct kvm *kvm, return -EINVAL; if (mem->guest_phys_addr & (PAGE_SIZE - 1)) return -EINVAL; - /* We can read the guest memory with __xxx_user() later on. */ if ((mem->userspace_addr & (PAGE_SIZE - 1)) || - (mem->userspace_addr !=3D untagged_addr(mem->userspace_addr)) || - !access_ok((void __user *)(unsigned long)mem->userspace_addr, + (mem->userspace_addr !=3D untagged_addr(mem->userspace_addr))) + return -EINVAL; + /* We can read the guest memory with __xxx_user() later on. */ + if (!(mem->flags & KVM_MEM_PRIVATE) && + !access_ok((void __user *)(unsigned long)mem->userspace_addr, mem->memory_size)) return -EINVAL; if (as_id >=3D KVM_ADDRESS_SPACE_NUM || id >=3D KVM_MEM_SLOTS_NUM) @@ -1821,6 +1843,8 @@ int __kvm_set_memory_region(struct kvm *kvm, new.npages =3D mem->memory_size >> PAGE_SHIFT; new.flags =3D mem->flags; new.userspace_addr =3D mem->userspace_addr; + new.file =3D NULL; + new.file_ofs =3D 0; =20 if (new.npages > KVM_MEM_MAX_NR_PAGES) return -EINVAL; @@ -1829,6 +1853,9 @@ int __kvm_set_memory_region(struct kvm *kvm, change =3D KVM_MR_CREATE; new.dirty_bitmap =3D NULL; } else { /* Modify an existing slot. */ + /* Private memslots are immutable, they can only be deleted. */ + if (mem->flags & KVM_MEM_PRIVATE) + return -EINVAL; if ((new.userspace_addr !=3D old.userspace_addr) || (new.npages !=3D old.npages) || ((new.flags ^ old.flags) & KVM_MEM_READONLY)) --=20 2.17.1