[PATCH v4 6/7] qemu: Update Cgroup, namespace, and seclabel for iommufd

7 Jan 2026

From: Nathan Chen <nathanc@nvidia.com>

When launching a qemu VM with the iommufd feature enabled for VFIO
hostdevs:
- Do not allow cgroup, namespace, and seclabel access to VFIO
paths (/dev/vfio/vfio and /dev/vfio/<iommugroup>)
- Allow access to iommufd paths (/dev/iommu and
/dev/vfio/devices/vfio*) for AppArmor, SELinux, and DAC

Signed-off-by: Nathan Chen <nathanc@nvidia.com>
---
 src/qemu/qemu_cgroup.c           | 26 +++++++-------
 src/qemu/qemu_namespace.c        | 16 +++++----
 src/security/security_apparmor.c | 32 +++++++++++++----
 src/security/security_dac.c      | 59 ++++++++++++++++++++++++++------
 src/security/security_selinux.c  | 57 ++++++++++++++++++++++++------
 src/security/virt-aa-helper.c    | 33 ++++++++++++++----
 6 files changed, 170 insertions(+), 53 deletions(-)

diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 7dadef0739..7190a4f80f 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -479,21 +479,23 @@ qemuSetupHostdevCgroup(virDomainObj *vm,
     g_autofree char *path = NULL;
     int perms;
 
-    if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES))
-        return 0;
+    if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+        if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES))
+            return 0;
 
-    if (qemuDomainGetHostdevPath(dev, &path, &perms) < 0)
-        return -1;
+        if (qemuDomainGetHostdevPath(dev, &path, &perms) < 0)
+            return -1;
 
-    if (path &&
-        qemuCgroupAllowDevicePath(vm, path, perms, false) < 0) {
-        return -1;
-    }
+        if (path &&
+            qemuCgroupAllowDevicePath(vm, path, perms, false) < 0) {
+            return -1;
+        }
 
-    if (virHostdevNeedsVFIO(dev) &&
-        qemuCgroupAllowDevicePath(vm, QEMU_DEV_VFIO,
-                                  VIR_CGROUP_DEVICE_RW, false) < 0) {
-        return -1;
+        if (virHostdevNeedsVFIO(dev) &&
+            qemuCgroupAllowDevicePath(vm, QEMU_DEV_VFIO,
+                                      VIR_CGROUP_DEVICE_RW, false) < 0) {
+            return -1;
+        }
     }
 
     return 0;
diff --git a/src/qemu/qemu_namespace.c b/src/qemu/qemu_namespace.c
index c689cc3e40..907b2773cf 100644
--- a/src/qemu/qemu_namespace.c
+++ b/src/qemu/qemu_namespace.c
@@ -345,15 +345,17 @@ qemuDomainSetupHostdev(virDomainObj *vm,
 {
     g_autofree char *path = NULL;
 
-    if (qemuDomainGetHostdevPath(hostdev, &path, NULL) < 0)
-        return -1;
+    if (hostdev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+        if (qemuDomainGetHostdevPath(hostdev, &path, NULL) < 0)
+            return -1;
 
-    if (path)
-        *paths = g_slist_prepend(*paths, g_steal_pointer(&path));
+        if (path)
+            *paths = g_slist_prepend(*paths, g_steal_pointer(&path));
 
-    if (virHostdevNeedsVFIO(hostdev) &&
-        (!hotplug || !qemuDomainNeedsVFIO(vm->def)))
-        *paths = g_slist_prepend(*paths, g_strdup(QEMU_DEV_VFIO));
+        if (virHostdevNeedsVFIO(hostdev) &&
+            (!hotplug || !qemuDomainNeedsVFIO(vm->def)))
+            *paths = g_slist_prepend(*paths, g_strdup(QEMU_DEV_VFIO));
+    }
 
     return 0;
 }
diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c
index 68ac39611f..362ca09562 100644
--- a/src/security/security_apparmor.c
+++ b/src/security/security_apparmor.c
@@ -848,14 +848,32 @@ AppArmorSetSecurityHostdevLabel(virSecurityManager *mgr,
             goto done;
 
         if (pcisrc->driver.name == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO) {
-            char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
-
-            if (!vfioGroupDev) {
-                virPCIDeviceFree(pci);
-                goto done;
+            if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+                char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
+
+                if (!vfioGroupDev) {
+                    virPCIDeviceFree(pci);
+                    goto done;
+                }
+                ret = AppArmorSetSecurityPCILabel(pci, vfioGroupDev, ptr);
+                VIR_FREE(vfioGroupDev);
+            } else {
+                g_autofree char *vfiofdDev = NULL;
+
+                if (virPCIDeviceGetVfioPath(&dev->source.subsys.u.pci.addr, &vfiofdDev) < 0)
+                    return -1;
+
+                if (!virIOMMUFDSupported())
+                    return -1;
+
+                ret = AppArmorSetSecurityPCILabel(pci, vfiofdDev, ptr);
+                if (ret)
+                    return ret;
+
+                ret = AppArmorSetSecurityPCILabel(pci, VIR_IOMMU_DEV_PATH, ptr);
+                if (ret)
+                    return ret;
             }
-            ret = AppArmorSetSecurityPCILabel(pci, vfioGroupDev, ptr);
-            VIR_FREE(vfioGroupDev);
         } else {
             ret = virPCIDeviceFileIterate(pci, AppArmorSetSecurityPCILabel, ptr);
         }
diff --git a/src/security/security_dac.c b/src/security/security_dac.c
index 2f788b872a..fbe216637f 100644
--- a/src/security/security_dac.c
+++ b/src/security/security_dac.c
@@ -41,6 +41,7 @@
 #include "virscsivhost.h"
 #include "virstring.h"
 #include "virutil.h"
+#include "viriommufd.h"
 
 #define VIR_FROM_THIS VIR_FROM_SECURITY
 
@@ -1282,14 +1283,32 @@ virSecurityDACSetHostdevLabel(virSecurityManager *mgr,
             return -1;
 
         if (pcisrc->driver.name == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO) {
-            g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
+            if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+                g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
 
-            if (!vfioGroupDev)
-                return -1;
+                if (!vfioGroupDev)
+                    return -1;
+
+                ret = virSecurityDACSetHostdevLabelHelper(vfioGroupDev,
+                                                          false,
+                                                          &cbdata);
+            } else {
+                g_autofree char *vfiofdDev = NULL;
+
+                if (virPCIDeviceGetVfioPath(&dev->source.subsys.u.pci.addr, &vfiofdDev) < 0)
+                    return -1;
 
-            ret = virSecurityDACSetHostdevLabelHelper(vfioGroupDev,
-                                                      false,
-                                                      &cbdata);
+                if (!virIOMMUFDSupported())
+                    return -1;
+
+                ret = virSecurityDACSetHostdevLabelHelper(vfiofdDev, false, &cbdata);
+                if (ret)
+                    return ret;
+
+                ret = virSecurityDACSetHostdevLabelHelper(VIR_IOMMU_DEV_PATH, false, &cbdata);
+                if (ret)
+                    return ret;
+            }
         } else {
             ret = virPCIDeviceFileIterate(pci,
                                           virSecurityDACSetPCILabel,
@@ -1443,13 +1462,33 @@ virSecurityDACRestoreHostdevLabel(virSecurityManager *mgr,
             return -1;
 
         if (pcisrc->driver.name == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO) {
-            g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
+            if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+                g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
 
-            if (!vfioGroupDev)
-                return -1;
+                if (!vfioGroupDev)
+                    return -1;
 
-            ret = virSecurityDACRestoreFileLabelInternal(mgr, NULL,
+                ret = virSecurityDACRestoreFileLabelInternal(mgr, NULL,
                                                          vfioGroupDev, false);
+            } else {
+                g_autofree char *vfiofdDev = NULL;
+
+                if (virPCIDeviceGetVfioPath(&dev->source.subsys.u.pci.addr, &vfiofdDev) < 0)
+                    return -1;
+
+                if (!virIOMMUFDSupported())
+                    return -1;
+
+                ret = virSecurityDACRestoreFileLabelInternal(mgr, NULL,
+                                                             vfiofdDev, false);
+                if (ret)
+                    return ret;
+
+                ret = virSecurityDACRestoreFileLabelInternal(mgr, NULL,
+                                                             VIR_IOMMU_DEV_PATH, false);
+                if (ret)
+                    return ret;
+            }
         } else {
             ret = virPCIDeviceFileIterate(pci, virSecurityDACRestorePCILabel, mgr);
         }
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 2f3cc274a5..05086ad9e1 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -41,6 +41,7 @@
 #include "virconf.h"
 #include "virtpm.h"
 #include "virstring.h"
+#include "viriommufd.h"
 
 #define VIR_FROM_THIS VIR_FROM_SECURITY
 
@@ -2256,14 +2257,32 @@ virSecuritySELinuxSetHostdevSubsysLabel(virSecurityManager *mgr,
             return -1;
 
         if (pcisrc->driver.name == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO) {
-            g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
+            if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+                g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
 
-            if (!vfioGroupDev)
-                return -1;
+                if (!vfioGroupDev)
+                    return -1;
+
+                ret = virSecuritySELinuxSetHostdevLabelHelper(vfioGroupDev,
+                                                              false,
+                                                              &data);
+            } else {
+                g_autofree char *vfiofdDev = NULL;
+
+                if (virPCIDeviceGetVfioPath(&dev->source.subsys.u.pci.addr, &vfiofdDev) < 0)
+                    return -1;
 
-            ret = virSecuritySELinuxSetHostdevLabelHelper(vfioGroupDev,
-                                                          false,
-                                                          &data);
+                if (!virIOMMUFDSupported())
+                    return -1;
+
+                ret = virSecuritySELinuxSetHostdevLabelHelper(vfiofdDev, false, &data);
+                if (ret)
+                    return ret;
+
+                ret = virSecuritySELinuxSetHostdevLabelHelper(VIR_IOMMU_DEV_PATH, false, &data);
+                if (ret)
+                    return ret;
+            }
         } else {
             ret = virPCIDeviceFileIterate(pci, virSecuritySELinuxSetPCILabel, &data);
         }
@@ -2491,12 +2510,30 @@ virSecuritySELinuxRestoreHostdevSubsysLabel(virSecurityManager *mgr,
             return -1;
 
         if (pcisrc->driver.name == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO) {
-            g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
+            if (dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
+                g_autofree char *vfioGroupDev = virPCIDeviceGetIOMMUGroupDev(pci);
 
-            if (!vfioGroupDev)
-                return -1;
+                if (!vfioGroupDev)
+                    return -1;
+
+                ret = virSecuritySELinuxRestoreFileLabel(mgr, vfioGroupDev, false, false);
+            } else {
+                g_autofree char *vfiofdDev = NULL;
+
+                if (virPCIDeviceGetVfioPath(&dev->source.subsys.u.pci.addr, &vfiofdDev) < 0)
+                    return -1;
 
-            ret = virSecuritySELinuxRestoreFileLabel(mgr, vfioGroupDev, false, false);
+                if (!virIOMMUFDSupported())
+                    return -1;
+
+                ret = virSecuritySELinuxRestoreFileLabel(mgr, vfiofdDev, false, false);
+                if (ret)
+                    return ret;
+
+                ret = virSecuritySELinuxRestoreFileLabel(mgr, VIR_IOMMU_DEV_PATH, false, false);
+                if (ret)
+                    return ret;
+            }
         } else {
             ret = virPCIDeviceFileIterate(pci, virSecuritySELinuxRestorePCILabel, mgr);
         }
diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
index de0a826063..43046ab831 100644
--- a/src/security/virt-aa-helper.c
+++ b/src/security/virt-aa-helper.c
@@ -50,6 +50,7 @@
 #include "virstring.h"
 #include "virgettext.h"
 #include "virhostdev.h"
+#include "viriommufd.h"
 
 #define VIR_FROM_THIS VIR_FROM_SECURITY
 
@@ -1114,8 +1115,9 @@ get_files(vahControl * ctl)
 
             virDeviceHostdevPCIDriverName driverName = dev->source.subsys.u.pci.driver.name;
 
-            if (driverName == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO ||
-                driverName == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_DEFAULT) {
+            if ((driverName == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_VFIO ||
+                driverName == VIR_DEVICE_HOSTDEV_PCI_DRIVER_NAME_DEFAULT) &&
+                dev->source.subsys.u.pci.driver.iommufd != VIR_TRISTATE_BOOL_YES) {
                 needsVfio = true;
             }
 
@@ -1348,6 +1350,7 @@ get_files(vahControl * ctl)
         virBufferAddLit(&buf, "  \"/dev/vfio/vfio\" rw,\n");
         virBufferAddLit(&buf, "  \"/dev/vfio/[0-9]*\" rw,\n");
     }
+
     if (needsgl) {
         /* if using gl all sorts of further dri related paths will be needed */
         virBufferAddLit(&buf, "  # DRI/Mesa/(e)GL config and driver paths\n");
@@ -1385,9 +1388,18 @@ get_files(vahControl * ctl)
         }
     }
 
-    if (ctl->newfile &&
-        vah_add_file(&buf, ctl->newfile, "rwk") != 0) {
-        return -1;
+    if (ctl->newfile) {
+        const char *perms = "rwk";
+
+        /* VFIO and iommufd devices need mmap permission */
+        if (STRPREFIX(ctl->newfile, "/dev/vfio/devices/vfio") ||
+            STREQ(ctl->newfile, VIR_IOMMU_DEV_PATH)) {
+            perms = "rwm";
+        }
+
+        if (vah_add_file(&buf, ctl->newfile, perms) != 0) {
+            return -1;
+        }
     }
 
     ctl->files = virBufferContentAndReset(&buf);
@@ -1561,8 +1573,15 @@ main(int argc, char **argv)
                 }
         }
         if (ctl->append && ctl->newfile) {
-            if (vah_add_file(&buf, ctl->newfile, "rwk") != 0)
-                goto cleanup;
+            const char *perms = "rwk";
+
+            if (STRPREFIX(ctl->newfile, "/dev/vfio/devices/vfio") ||
+                STREQ(ctl->newfile, VIR_IOMMU_DEV_PATH)) {
+                perms = "rwm";
+            }
+
+            if (vah_add_file(&buf, ctl->newfile, perms) != 0)
+                return -1;
         } else {
             if (ctl->def->virtType == VIR_DOMAIN_VIRT_QEMU ||
                 ctl->def->virtType == VIR_DOMAIN_VIRT_KQEMU ||
-- 
2.43.0

    