linux-kernel - [PATCH v2 21/22] vfio: selftests: Verify that opening VFIO device fails during Live Update

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260129212510.967611-22-dmatlack@google.com>
Date: Thu, 29 Jan 2026 21:25:08 +0000
From: David Matlack <dmatlack@...gle.com>
To: Alex Williamson <alex@...zbot.org>
Cc: Adithya Jayachandran <ajayachandra@...dia.com>, Alexander Graf <graf@...zon.com>, 
	Alex Mastro <amastro@...com>, Alistair Popple <apopple@...dia.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Ankit Agrawal <ankita@...dia.com>, 
	Bjorn Helgaas <bhelgaas@...gle.com>, Chris Li <chrisl@...nel.org>, 
	David Matlack <dmatlack@...gle.com>, David Rientjes <rientjes@...gle.com>, 
	Jacob Pan <jacob.pan@...ux.microsoft.com>, Jason Gunthorpe <jgg@...dia.com>, 
	Jason Gunthorpe <jgg@...pe.ca>, Jonathan Corbet <corbet@....net>, Josh Hilke <jrhilke@...gle.com>, 
	Kevin Tian <kevin.tian@...el.com>, kexec@...ts.infradead.org, kvm@...r.kernel.org, 
	Leon Romanovsky <leon@...nel.org>, Leon Romanovsky <leonro@...dia.com>, linux-doc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org, 
	linux-mm@...ck.org, linux-pci@...r.kernel.org, Lukas Wunner <lukas@...ner.de>, 
	"Michał Winiarski" <michal.winiarski@...el.com>, Mike Rapoport <rppt@...nel.org>, 
	Parav Pandit <parav@...dia.com>, Pasha Tatashin <pasha.tatashin@...een.com>, 
	Pranjal Shrivastava <praan@...gle.com>, Pratyush Yadav <pratyush@...nel.org>, 
	Raghavendra Rao Ananta <rananta@...gle.com>, Rodrigo Vivi <rodrigo.vivi@...el.com>, 
	Saeed Mahameed <saeedm@...dia.com>, Samiullah Khawaja <skhawaja@...gle.com>, 
	Shuah Khan <skhan@...uxfoundation.org>, 
	"Thomas Hellström" <thomas.hellstrom@...ux.intel.com>, Tomita Moeko <tomitamoeko@...il.com>, 
	Vipin Sharma <vipinsh@...gle.com>, Vivek Kasireddy <vivek.kasireddy@...el.com>, 
	William Tu <witu@...dia.com>, Yi Liu <yi.l.liu@...el.com>, Zhu Yanjun <yanjun.zhu@...ux.dev>
Subject: [PATCH v2 21/22] vfio: selftests: Verify that opening VFIO device
 fails during Live Update

Verify that opening a VFIO device through its cdev file and via
VFIO_GROUP_GET_DEVICE_FD both fail with -EBUSY if the device was
preserved across a Live Update. When a device file is preserve across a
Live Update, the file must be retrieved from /dev/liveupdate, not from
VFIO directly.

Signed-off-by: David Matlack <dmatlack@...gle.com>
---
 .../vfio/vfio_pci_liveupdate_kexec_test.c     | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c b/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c
index 15b3e3af91d1..65c48196e44e 100644
--- a/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c
@@ -36,6 +36,42 @@ static void before_kexec(int luo_fd)
 	daemonize_and_wait();
 }
 
+static void check_open_vfio_device_fails(void)
+{
+	const char *cdev_path = vfio_pci_get_cdev_path(device_bdf);
+	struct vfio_pci_device *device;
+	struct iommu *iommu;
+	int ret, i;
+
+	printf("Checking open(%s) fails\n", cdev_path);
+	ret = open(cdev_path, O_RDWR);
+	VFIO_ASSERT_EQ(ret, -1);
+	VFIO_ASSERT_EQ(errno, EBUSY);
+	free((void *)cdev_path);
+
+	for (i = 0; i < nr_iommu_modes; i++) {
+		if (!iommu_modes[i].container_path)
+			continue;
+
+		iommu = iommu_init(iommu_modes[i].name);
+
+		device = vfio_pci_device_alloc(device_bdf, iommu);
+		vfio_pci_group_setup(device);
+		vfio_pci_iommu_setup(device);
+
+		printf("Checking ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, \"%s\") fails (%s)\n",
+		       device_bdf, iommu_modes[i].name);
+
+		ret = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, device->bdf);
+		VFIO_ASSERT_EQ(ret, -1);
+		VFIO_ASSERT_EQ(errno, EBUSY);
+
+		close(device->group_fd);
+		free(device);
+		iommu_cleanup(iommu);
+	}
+}
+
 static void after_kexec(int luo_fd, int state_session_fd)
 {
 	struct vfio_pci_device *device;
@@ -44,6 +80,8 @@ static void after_kexec(int luo_fd, int state_session_fd)
 	int device_fd;
 	int stage;
 
+	check_open_vfio_device_fails();
+
 	restore_and_read_stage(state_session_fd, STATE_TOKEN, &stage);
 	VFIO_ASSERT_EQ(stage, 2);
 
-- 
2.53.0.rc1.225.gd81095ad13-goog