[libvirt] [PATCH v2 07/39] qemu: Explicitly add/remove /dev/vfio/vfio to/from NS/CGroups

[Michal Privoznik]

In near future, the decision what to do with /dev/vfio/vfio with
respect to domain namespace and CGroup is going to be moved out
of qemuDomainGetHostdevPath() because there will be some other
types of devices than hostdevs that need access to VFIO.

All functions that I'm changing assume that hostdev we are
adding/removing to VM is not in the definition yet (because of
how qemuDomainNeedsVFIO() is written). Fortunately, this
assumption is true.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/qemu/qemu_cgroup.c | 48 +++++++++++++++++++++++++++++++++++++++++-
 src/qemu/qemu_domain.c | 36 +++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 4d6f0c33cd..f110b49d16 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -25,6 +25,7 @@
 #include "qemu_domain.h"
 #include "qemu_process.h"
 #include "qemu_extdevice.h"
+#include "qemu_hostdev.h"
 #include "vircgroup.h"
 #include "virlog.h"
 #include "viralloc.h"
@@ -360,6 +361,17 @@ qemuTeardownInputCgroup(virDomainObjPtr vm,
 }
 
 
+/**
+ * qemuSetupHostdevCgroup:
+ * vm: domain object
+ * @dev: device to allow
+ *
+ * For given host device @dev allow access to in Cgroups.
+ * Note, @dev must not be in @vm's definition.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise.
+ */
 int
 qemuSetupHostdevCgroup(virDomainObjPtr vm,
                        virDomainHostdevDefPtr dev)
@@ -386,6 +398,17 @@ qemuSetupHostdevCgroup(virDomainObjPtr vm,
             goto cleanup;
     }
 
+    if (qemuHostdevNeedsVFIO(dev) &&
+        !qemuDomainNeedsVFIO(vm->def)) {
+        VIR_DEBUG("Cgroup allow %s perms=%d", QEMU_DEV_VFIO, VIR_CGROUP_DEVICE_RW);
+        rv = virCgroupAllowDevicePath(priv->cgroup, QEMU_DEV_VFIO,
+                                      VIR_CGROUP_DEVICE_RW, false);
+        virDomainAuditCgroupPath(vm, priv->cgroup, "allow",
+                                 QEMU_DEV_VFIO, "rw", rv);
+        if (rv < 0)
+            goto cleanup;
+    }
+
     ret = 0;
 
  cleanup:
@@ -396,9 +419,21 @@ qemuSetupHostdevCgroup(virDomainObjPtr vm,
     return ret;
 }
 
+
+/**
+ * qemuTeardownHostdevCgroup:
+ * @vm: doamin object
+ * @dev: device to tear down
+ *
+ * For given host device @dev deny access to it in CGroups.
+ * Note, @dev must not be in @vm's definition.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise.
+ */
 int
 qemuTeardownHostdevCgroup(virDomainObjPtr vm,
-                       virDomainHostdevDefPtr dev)
+                          virDomainHostdevDefPtr dev)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
     char **path = NULL;
@@ -422,6 +457,17 @@ qemuTeardownHostdevCgroup(virDomainObjPtr vm,
             goto cleanup;
     }
 
+    if (qemuHostdevNeedsVFIO(dev) &&
+        !qemuDomainNeedsVFIO(vm->def)) {
+        VIR_DEBUG("Cgroup deny " QEMU_DEV_VFIO);
+        rv = virCgroupDenyDevicePath(priv->cgroup, QEMU_DEV_VFIO,
+                                     VIR_CGROUP_DEVICE_RWM, false);
+        virDomainAuditCgroupPath(vm, priv->cgroup, "deny",
+                                 QEMU_DEV_VFIO, "rwm", rv);
+        if (rv < 0)
+            goto cleanup;
+    }
+
     ret = 0;
  cleanup:
     for (i = 0; i < npaths; i++)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 6502c6191c..02b6e590cd 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -13540,6 +13540,10 @@ qemuDomainSetupHostdev(virQEMUDriverConfigPtr cfg ATTRIBUTE_UNUSED,
             goto cleanup;
     }
 
+    if (qemuHostdevNeedsVFIO(dev) &&
+        qemuDomainCreateDevice(QEMU_DEV_VFIO, data, false) < 0)
+        goto cleanup;
+
     ret = 0;
  cleanup:
     for (i = 0; i < npaths; i++)
@@ -14576,6 +14580,17 @@ qemuDomainNamespaceTeardownDisk(virDomainObjPtr vm ATTRIBUTE_UNUSED,
 }
 
 
+/**
+ * qemuDomainNamespaceSetupHostdev:
+ * @vm: domain object
+ * @hostdev: hostdev to create in @vm's namespace
+ *
+ * For given @hostdev, create its devfs representation (if it has one) in
+ * domain namespace. Note, @hostdev must not be in @vm's definition.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise.
+ */
 int
 qemuDomainNamespaceSetupHostdev(virDomainObjPtr vm,
                                 virDomainHostdevDefPtr hostdev)
@@ -14590,6 +14605,11 @@ qemuDomainNamespaceSetupHostdev(virDomainObjPtr vm,
     if (qemuDomainNamespaceMknodPaths(vm, (const char **)paths, npaths) < 0)
         goto cleanup;
 
+    if (qemuHostdevNeedsVFIO(hostdev) &&
+        !qemuDomainNeedsVFIO(vm->def) &&
+        qemuDomainNamespaceMknodPath(vm, QEMU_DEV_VFIO) < 0)
+        goto cleanup;
+
     ret = 0;
  cleanup:
     for (i = 0; i < npaths; i++)
@@ -14599,6 +14619,17 @@ qemuDomainNamespaceSetupHostdev(virDomainObjPtr vm,
 }
 
 
+/**
+ * qemuDomainNamespaceTeardownHostdev:
+ * @vm: domain object
+ * @hostdev: hostdev to remove in @vm's namespace
+ *
+ * For given @hostdev, remove its devfs representation (if it has one) in
+ * domain namespace. Note, @hostdev must not be in @vm's definition.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise.
+ */
 int
 qemuDomainNamespaceTeardownHostdev(virDomainObjPtr vm,
                                    virDomainHostdevDefPtr hostdev)
@@ -14614,6 +14645,11 @@ qemuDomainNamespaceTeardownHostdev(virDomainObjPtr vm,
     if (qemuDomainNamespaceUnlinkPaths(vm, (const char **)paths, npaths) < 0)
         goto cleanup;
 
+    if (qemuHostdevNeedsVFIO(hostdev) &&
+        !qemuDomainNeedsVFIO(vm->def) &&
+        qemuDomainNamespaceUnlinkPath(vm, QEMU_DEV_VFIO) < 0)
+        goto cleanup;
+
     ret = 0;
  cleanup:
     for (i = 0; i < npaths; i++)
-- 
2.21.0