From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F6133115AE; Sat, 26 Sep 2026 00:50:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790383852; cv=none; b=DwkKS+IpOKomZoI6ia1v2QASbYAg0OoFI/wfzi9UVPGVBkP36aioemNSd5Cr7edtpSIZGosG17QmqxwMBXxbC6a5y4hCb3RDa83SyqzFCvFMzskuNjaKNH4a2QG9eJjWxsvXwAFz7Onnx9b22se8JHs6oO2KnjZKkzwbKyQ07QI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790383852; c=relaxed/simple; bh=ZQkHIEo90myH/etAY2BZvV0PdV/I+2f0qu5W0si1/Vg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=n7LAbc4VvmUpOyU+mho8QrxoeO0+HkHZIWuMqZhZTbQV4ZSqgX+liFbp7dm46h0j0E5zjLNv1R+o0N4+VJP7Q/hdn18O/yvgDReaDRSeqaqv6Xaz3ICTLjTHuiwbkDF9C9EB2LYCIHdIFG9kSpiSIXwJJKTuQfg2311okvi0wI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gnu/hdLL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gnu/hdLL" Received: by smtp.kernel.org (Postfix) with ESMTPS id C714DC2BD01; Sat, 26 Sep 2026 00:50:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1790383851; bh=ZQkHIEo90myH/etAY2BZvV0PdV/I+2f0qu5W0si1/Vg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=gnu/hdLL/8rQ1eCpICBDMgQ5bdAfMXUZB6QclisY2veSfL3KWIII4fqBZJYUbNLXp gQeewK6auA3yOn1u0DybDlBl1Ma8sRYeKLTxqDUEH0E9tQKvnfdlPLP1VBfE1GIjZh OIp5kyd8evCiqHhDMCft3eUwZrsrYf6hOBXhO/DHPmm664vH5pQ4Y8xto2O7yG7Lw/ Gyk79kiUiMgS4apZ8IdUqc+/Cp8VQNlKPRNIrQUzir4XO3B78NowK3TpB0eaqESPmR UL1NrQQMWmCfQgNokiG42aDhn2vItl+BXAterA85xlL75uU2yAvZZ+J5uO+Gy5hR7L IDfa0vpXFdngA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2F4BC98331; Sat, 26 Sep 2026 00:50:51 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Fri, 25 Sep 2026 17:50:55 -0700 Subject: [PATCH RFC 08/17] KVM: selftests: Test rejection of tmpfs file for resource_fd Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260925-gmem-tmpfs-backend-v1-8-d36159822d18@google.com> References: <20260925-gmem-tmpfs-backend-v1-0-d36159822d18@google.com> In-Reply-To: <20260925-gmem-tmpfs-backend-v1-0-d36159822d18@google.com> To: Hugh Dickins , Baolin Wang , Andrew Morton , Sean Christopherson , Paolo Bonzini , David Hildenbrand , Jonathan Corbet , Shuah Khan , Randy Dunlap , Shuah Khan , vannapurve@google.com, erdemaktas@google.com, jxgao@google.com, rientjes@google.com, fvdl@google.com, jthoughton@google.com, tarunsahu@google.com, pratyush@kernel.org, fuad.tabba@linux.dev, Gregory Price , David Woodhouse , yan.y.zhao@intel.com, michael.roth@amd.com, suzuki.poulose@arm.com, Christian Brauner , Jason Gunthorpe , Nicolin Chen , Xu Yilun , aik@amd.com, aneesh.kumar@kernel.org, Vlastimil Babka Cc: kernel-team@android.com, kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Ackerley Tng X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1790383850; l=1833; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=pY+7zel/xk6auUHj9TI6BcpE5A6Lb+XZc+WYc5WnDfM=; b=6ICqdR//hE/RTxLIzxROFfy94V96cNAwZqPG5viJrO4RVBZA3wcH6/zTFcVp2BIl7ddnTJ1D3 XWEO8D7UwtkBxgYBX0V2bQmanCnt1ukpEayqoKxStzdpPNHwXUpIqF5 X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Ackerley Tng Add test coverage verifying that passing a regular file from tmpfs as a resource file fails with ENOTDIR. Only directory file descriptors representing the mount root are supported as resource pools. Signed-off-by: Ackerley Tng --- tools/testing/selftests/kvm/guest_memfd_test.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 31bc74c4c26bd..a7a1b5470cb2c 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -457,6 +457,26 @@ static void test_resource_fd_unsupported_fs(struct kvm_vm *vm) close(file_fd); } +static void test_resource_fd_tmpfs_file(struct kvm_vm *vm) +{ + int fd, file_fd; + + /* + * Passing a regular file from tmpfs (e.g. via memfd) is rejected by + * the provider attach callback with ENOTDIR because only directory + * FDs representing the mount root are supported resource pools. + */ + file_fd = memfd_create("test_tmpfs_file", 0); + TEST_ASSERT(file_fd >= 0, "memfd_create failed"); + + fd = __vm_create_guest_memfd_resource(vm, page_size, + GUEST_MEMFD_FLAG_USE_RESOURCE, + file_fd); + TEST_ASSERT(fd < 0, "guest_memfd with tmpfs file fd should fail"); + TEST_ASSERT_EQ(errno, ENOTDIR); + close(file_fd); +} + #define ____gmem_test(__test, __vm, __flags, __gmem_size, args...) \ do { \ int fd = vm_create_guest_memfd(__vm, __gmem_size, __flags); \ @@ -517,6 +537,7 @@ static void test_guest_memfd(unsigned long vm_type) test_resource_fd_invalid(vm); test_resource_fd_unsupported_fs(vm); + test_resource_fd_tmpfs_file(vm); __test_guest_memfd(vm, 0); -- 2.56.0.rc1.315.gc6ed9934b7-goog