From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793000537; b=4Bmu6lJzvDQUgA0FQ8orRG9vbuwnXtGuETPMeVmg1/dcYXK00NJ25lBAhCmAaKM3pC2t 2c3PulWzPSUaQxxAeoqk1hMMPi+gqw3ScQVjNu1PwFdSXavFF1cHeUbvR2KHxEUF+HbiR h6vqZyQs3sHyw6Q78KqsjAXAHD6ZKE/Xko2aVxErE9NgsMDIgeEcHrvcBXW5qEjuXstHb 4728G12LUZCdXM6C5XBDLPgGHS+yNU7PbJlwupv8t2GNCqr1dUTG7IwO8Qf2pXR+rXrMW HX8nAi9IptQdKShRAdTXhGiJaEPPVug1Dq/52Tc/s9fdTeBRHTTdOYb64wHfWVlmyKw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793000537; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=QK09cvCCv1U2VbXXs4aXYBwdDy0Jn6Y8NtPS8Cb2LSk=; b=AovLTzQf9ZlKzDhEjJizb+f1mojlBXq0TP+B+ekk8aOc6Xe4Bl6fLFaTf95PB5FmPzCg auALs0mfaqYlkbP91bi+GnKLdXjVmNIRTn9RBLxHkne5fWBFb2LUzQYYhnaZptlehmxn2 4QoGPZVQ9oV3c4C1Vshejj8rvr6NPJI0/na/vO1NS6LOXekE06hUfO7Gfhb4+8gmSnqHr DAtStmN0vf0yzY2tfHW2aBkQ2H5bbbhw804CvnsPotogNUKKItmEJ8/8YSo5F3s4TfSlW 82XkHRDv71F00KnyETw1I6Xfux9kyLqLO5ZPwHBzZRdnsvuFGi5iNk861rMJRpAbSvA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Zz1SyuAS; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9E103606A31A for ; Mon, 26 Oct 2026 07:42:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Zz1SyuAS Received: by smtp.kernel.org (Postfix) with ESMTPSA id F420F1F01825; Mon, 26 Oct 2026 07:42:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793000537; bh=QK09cvCCv1U2VbXXs4aXYBwdDy0Jn6Y8NtPS8Cb2LSk=; h=From:Subject:Reply-To:To:In-Reply-To:References:Date; b=Zz1SyuASBC+eJsHXA5Wv5i8DneYUcveOWukvOTNfkeEwlSUTilmpcFF3r3LDzaOPt 81pt2O99nRR7S6JTKWaegQ3MDZ8lavjuYsFhUaPmrdvarAnxHKfVmXmB+qdBh0ZbGm 1XRtqzZ4Juqw+1U2e+YX4AGjwgAjxS531nQbk58y/mN6onG/pEXrCYi+YVrKQbcJeB 3cnBDSyxZ/cRqrWj1fGAEAZUqquXcI+xcuhD7i1yICCPUcYkZC/NPTUXpiBkVw09ED Y/rZYFZPDHApe/UwD6LJjjRwZSuLESMCnjGN5GqBACkycvaptg9n/KLZ8pT62Ez8HX RtjtVBmmlwrnw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v3 4/5] KVM: selftests: Add tests for KVM_LINK_GUEST_MEMFD ioctl Reply-To: sashiko-reviews@lists.linux.dev To: "Tao Gong" , kvm@vger.kernel.org In-Reply-To: <20261026064424.3003536-5-gongtao@google.com> References: <20261026064424.3003536-1-gongtao@google.com> <20261026064424.3003536-5-gongtao@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 26 Oct 2026 07:42:16 +0000 X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] KVM: selftests: test_link() hits vm->type assert in ____vm_creat= e() on arm64 -- commit c8e0fca46d65aef6ffa609495f3f615b1c614301 Author: Ackerley Tng KVM: selftests: Add tests for KVM_LINK_GUEST_MEMFD ioctl This commit adds kselftest helpers and test cases in guest_memfd_test.c for the KVM_LINK_GUEST_MEMFD ioctl, covering invalid inputs and valid linking between VMs. > diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testi= ng/selftests/kvm/guest_memfd_test.c > index 2233d871a38f4..ccde4d735c77c 100644 > --- a/tools/testing/selftests/kvm/guest_memfd_test.c > +++ b/tools/testing/selftests/kvm/guest_memfd_test.c > @@ -418,6 +418,68 @@ static void test_guest_memfd_flags(struct kvm_vm *vm) > } > } > =20 > +static void test_link(struct kvm_vm *vm, int src_fd, size_t total_size) > +{ > + struct kvm_link_guest_memfd params =3D {}; > + struct stat src_stat, dst_stat; > + struct kvm_vm *dst_vm; > + int dst_fd, bad_fd; > + int ret; > + > + /* guest_memfd can only be linked between VMs of the same type. */ > + dst_vm =3D vm_create_barebones_type(vm->type); [Severity: Medium] Will passing vm->type to vm_create_barebones_type() here trigger an assertion failure in ____vm_create() on arm64 when vm->pa_bits !=3D 40? On arm64, main() invokes test_guest_memfd(VM_TYPE_DEFAULT) with vm_type =3D= 0, and the initial vm_create_barebones_type(vm_type) call in test_guest_memfd() reaches tools/testing/selftests/kvm/lib/kvm_util.c:____vm_create(): #ifdef __aarch64__ TEST_ASSERT(!vm->type, "ARM doesn't support test-provided types"); if (vm->pa_bits !=3D 40) vm->type =3D KVM_VM_TYPE_ARM_IPA_SIZE(vm->pa_bits); #endif When the selected default guest mode has a physical address width other than 40 bits (for example on hosts where guest_modes_append_default() selects a 48-bit or 52-bit IPA mode), ____vm_create() overwrites vm->type in place with a non-zero KVM_VM_TYPE_ARM_IPA_SIZE(vm->pa_bits) value. When __test_guest_memfd() then calls test_link(), passing that mutated vm->type into vm_create_barebones_type(vm->type) forwards a non-zero shape.type into ____vm_create(), tripping TEST_ASSERT(!vm->type, ...). --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261026064424.3003= 536-1-gongtao@google.com?part=3D4