From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3AAD060A5BE3 for ; Wed, 11 Nov 2026 14:58:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=WPAPHZNE; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=X3e0Wc1/ DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=0Ka4B54p4sbNSrKWCL5vmxStgm56wKqIdQXQP7NpVRo=; b=WPAPHZNERRCj9n nPhZkyFeOyzoaKg48evSE6oWr1nzrwLMwBiHx7C1/uTak71U1v5mw8tHBHCJEzC2Jpx0P7z1NsoL9 InU1Sg9tUYJNWbrwUWM6a4tiDzkMWliMaY/oofQK+qeyLL+p3wAath+ERTlbHvNlCBYa66j+sBNbP K6fMsZVnrmg3qcEkqEyO1xMvdoqbO5A75ADqsLWX8CvGrBRSN4Mg70Dyz/jmmktR/Nmm/jsefE5o0 RhvoDX8R9Drou+TVMecfY8EJuAFv1sZ+d91UHoDDbOw3s7ps56i3nyBDQ5K+ZwG+JS8YnQQwLunZe G7mlD4Gddia7sAytCUSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR9mK-000000071GG-0Pcg; Wed, 11 Nov 2026 14:58:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR9mH-000000071Ff-3oNb for linux-arm-kernel@lists.infradead.org; Wed, 11 Nov 2026 14:58:23 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2D4451576; Wed, 11 Nov 2026 06:58:18 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.58.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 15E543F632; Wed, 11 Nov 2026 06:58:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794409101; bh=NjxaS8I7MBNoFlMkwcao+kYJE29WlG8theUiJeEC/vw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X3e0Wc1/bN5bK9Ydsdu6zV09TsnIebWg/y9m0yQFn3yRev5oCDqWrAmOpJ6HKTQSC k8rj8D0X02zItqh4PirYbFj9NweU0t+5nvq2tL2tUMQbEWfnaNHvzLfNu+rm6XtPfc cGk64C6WI0FBVFg4aJuvdty3QPE5KKaTdwThiEJg= From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi , Kohei Enju Subject: [PATCH v2 02/12] KVM: arm64: guest_memfd: Check mmap support when preparing memslot Date: Wed, 11 Nov 2026 14:57:46 +0000 Message-ID: <20261111145758.217946-3-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261111145758.217946-1-steven.price@arm.com> References: <20261111145758.217946-1-steven.price@arm.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261111_065822_040332_4EC6CC96 X-CRM114-Status: GOOD ( 13.53 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Check the guest_memfd backing file when deciding whether an arm64 memslot has mappable memory rather than checking whether the slot is gmem only. A public helper function is added to be able to reuse the static kvm_gmem_supports_mmap() function. Signed-off-by: Steven Price --- Changes since v1: - New patch in v2. Check the guest_memfd backing file rather than the memslot flag when deciding whether arm64 can map the backing memory. --- arch/arm64/kvm/mmu.c | 7 ++++--- include/linux/kvm_host.h | 1 + virt/kvm/guest_memfd.c | 6 ++++++ 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 1db10d8d6db7..a146f6cde3d0 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2839,10 +2839,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return -EFAULT; /* - * Only support guest_memfd backed memslots with mappable memory, since - * there aren't any CoCo VMs that support only private memory on arm64. + * Protected VMs currently require guest_memfd backed memslots with + * mappable memory to support shared mappings. */ - if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new)) + if (kvm_arch_has_private_mem(kvm) && kvm_slot_has_gmem(new) && + !kvm_gmem_slot_supports_mmap(new)) return -EINVAL; /* guest_memfd is incompatible with MTE. */ diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index e7fc94e2910a..f65728a713ec 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2614,6 +2614,7 @@ static inline bool kvm_is_private_gfn(struct kvm *kvm, gfn_t gfn) #ifdef CONFIG_KVM_GUEST_MEMFD bool kvm_gmem_is_private_gfn(struct kvm *kvm, gfn_t gfn); +bool kvm_gmem_slot_supports_mmap(const struct kvm_memory_slot *slot); bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm); static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 8c97a69b16dc..3dd8d227bebb 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -442,6 +442,12 @@ static bool kvm_gmem_supports_mmap(struct inode *inode) return GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_MMAP; } +bool kvm_gmem_slot_supports_mmap(const struct kvm_memory_slot *slot) +{ + /* The guest_memfd file is pinned while preparing a new memslot. */ + return kvm_gmem_supports_mmap(file_inode(slot->gmem.file)); +} + static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf) { struct inode *inode = file_inode(vmf->vma->vm_file); -- 2.43.0