Mediated devices support hot-{plug,unplug} since their introduction in
kernel 4.10, however this feature has been missing in libvirt since
commit ec783d7c introduced a hostdev type for mdevs.

Signed-off-by: Erik Skultety <eskultet@redhat.com>
---
 src/qemu/qemu_hotplug.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 6ec401e21..4abc7393b 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -2567,6 +2567,88 @@ qemuDomainAttachSCSIVHostDevice(virQEMUDriverPtr driver,
 }
 
 
+static int
+qemuDomainAttachMediatedDevice(virQEMUDriverPtr driver,
+                               virDomainObjPtr vm,
+                               virDomainHostdevDefPtr hostdev)
+{
+    int ret = -1;
+    char *devstr = NULL;
+    bool added = false;
+    bool teardowncgroup = false;
+    bool teardownlabel = false;
+    bool teardowndevice = false;
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    virDomainDeviceDef dev = { VIR_DOMAIN_DEVICE_HOSTDEV,
+                                { .hostdev = hostdev } };
+
+    if (qemuDomainEnsurePCIAddress(vm, &dev, driver) < 0)
+        return -1;
+
+    if (qemuHostdevPrepareMediatedDevices(driver,
+                                          vm->def->name,
+                                          &hostdev,
+                                          1) < 0)
+        goto cleanup;
+    added = true;
+
+    if (qemuDomainNamespaceSetupHostdev(vm, hostdev) < 0)
+        goto cleanup;
+    teardowndevice = true;
+
+    if (qemuSetupHostdevCgroup(vm, hostdev) < 0)
+        goto cleanup;
+    teardowncgroup = true;
+
+    if (qemuSecuritySetHostdevLabel(driver, vm, hostdev) < 0)
+        goto cleanup;
+    teardownlabel = true;
+
+    if (qemuAssignDeviceHostdevAlias(vm->def, &hostdev->info->alias, -1) < 0)
+        goto cleanup;
+
+    if (!(devstr = qemuBuildHostdevMediatedDevStr(vm->def, hostdev,
+                                                  priv->qemuCaps)))
+        goto cleanup;
+
+    if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs+1) < 0)
+        goto cleanup;
+
+    qemuDomainObjEnterMonitor(driver, vm);
+    ret = qemuMonitorAddDevice(priv->mon, devstr);
+    if (qemuDomainObjExitMonitor(driver, vm) < 0) {
+        ret = -1;
+        goto cleanup;
+    }
+
+    virDomainAuditHostdev(vm, hostdev, "attach", ret == 0);
+    if (ret < 0)
+        goto cleanup;
+
+    VIR_APPEND_ELEMENT_INPLACE(vm->def->hostdevs, vm->def->nhostdevs, hostdev);
+    ret = 0;
+ cleanup:
+    if (ret < 0) {
+        if (teardowncgroup && qemuTeardownHostdevCgroup(vm, hostdev) < 0)
+            VIR_WARN("Unable to remove host device cgroup ACL on hotplug fail");
+        if (teardownlabel &&
+            qemuSecurityRestoreHostdevLabel(driver, vm, hostdev) < 0)
+            VIR_WARN("Unable to restore host device labelling on hotplug fail");
+        if (teardowndevice &&
+            qemuDomainNamespaceTeardownHostdev(vm, hostdev) < 0)
+            VIR_WARN("Unable to remove host device from /dev");
+        if (added)
+            qemuHostdevReAttachMediatedDevices(driver,
+                                               vm->def->name,
+                                               vm->def->hostdevs,
+                                               vm->def->nhostdevs);
+        qemuDomainReleaseDeviceAddress(vm, hostdev->info, NULL);
+    }
+    VIR_FREE(devstr);
+    return ret;
+}
+
+
 int
 qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
                            virDomainObjPtr vm,
@@ -2602,6 +2684,10 @@ qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
         if (qemuDomainAttachSCSIVHostDevice(driver, vm, hostdev) < 0)
             goto error;
         break;
+    case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV:
+        if (qemuDomainAttachMediatedDevice(driver, vm, hostdev) < 0)
+            goto error;
+        break;
 
     default:
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-- 
2.14.3

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On Tue, Mar 27, 2018 at 10:57:14 +0200, Erik Skultety wrote:
> Mediated devices support hot-{plug,unplug} since their introduction in
> kernel 4.10, however this feature has been missing in libvirt since
> commit ec783d7c introduced a hostdev type for mdevs.

I think the feature was missing since d77e1a9642fe1efe9aa5f737a640354.

> 
> Signed-off-by: Erik Skultety <eskultet@redhat.com>
> ---
>  src/qemu/qemu_hotplug.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 86 insertions(+)
> 
> diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
> index 6ec401e21..4abc7393b 100644
> --- a/src/qemu/qemu_hotplug.c
> +++ b/src/qemu/qemu_hotplug.c
> @@ -2567,6 +2567,88 @@ qemuDomainAttachSCSIVHostDevice(virQEMUDriverPtr driver,
>  }
>  
>  
> +static int
> +qemuDomainAttachMediatedDevice(virQEMUDriverPtr driver,
> +                               virDomainObjPtr vm,
> +                               virDomainHostdevDefPtr hostdev)
> +{
> +    int ret = -1;
> +    char *devstr = NULL;
> +    bool added = false;
> +    bool teardowncgroup = false;
> +    bool teardownlabel = false;
> +    bool teardowndevice = false;
> +    qemuDomainObjPrivatePtr priv = vm->privateData;
> +    virDomainDeviceDef dev = { VIR_DOMAIN_DEVICE_HOSTDEV,
> +                                { .hostdev = hostdev } };
> +
> +    if (qemuDomainEnsurePCIAddress(vm, &dev, driver) < 0)
> +        return -1;
> +
> +    if (qemuHostdevPrepareMediatedDevices(driver,
> +                                          vm->def->name,
> +                                          &hostdev,
> +                                          1) < 0)
> +        goto cleanup;
> +    added = true;
> +
> +    if (qemuDomainNamespaceSetupHostdev(vm, hostdev) < 0)
> +        goto cleanup;
> +    teardowndevice = true;
> +
> +    if (qemuSetupHostdevCgroup(vm, hostdev) < 0)
> +        goto cleanup;
> +    teardowncgroup = true;
> +
> +    if (qemuSecuritySetHostdevLabel(driver, vm, hostdev) < 0)
> +        goto cleanup;
> +    teardownlabel = true;
> +
> +    if (qemuAssignDeviceHostdevAlias(vm->def, &hostdev->info->alias, -1) < 0)
> +        goto cleanup;
> +
> +    if (!(devstr = qemuBuildHostdevMediatedDevStr(vm->def, hostdev,
> +                                                  priv->qemuCaps)))
> +        goto cleanup;

Usually we'd call this prior to setting up everything, bug given that
this does not do any validation it's okay.

> +
> +    if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs+1) < 0)

Spaces around + sign.

> +        goto cleanup;
> +
> +    qemuDomainObjEnterMonitor(driver, vm);
> +    ret = qemuMonitorAddDevice(priv->mon, devstr);
> +    if (qemuDomainObjExitMonitor(driver, vm) < 0) {
> +        ret = -1;
> +        goto cleanup;
> +    }
> +
> +    virDomainAuditHostdev(vm, hostdev, "attach", ret == 0);
> +    if (ret < 0)
> +        goto cleanup;
> +
> +    VIR_APPEND_ELEMENT_INPLACE(vm->def->hostdevs, vm->def->nhostdevs, hostdev);
> +    ret = 0;
> + cleanup:
> +    if (ret < 0) {
> +        if (teardowncgroup && qemuTeardownHostdevCgroup(vm, hostdev) < 0)
> +            VIR_WARN("Unable to remove host device cgroup ACL on hotplug fail");
> +        if (teardownlabel &&
> +            qemuSecurityRestoreHostdevLabel(driver, vm, hostdev) < 0)
> +            VIR_WARN("Unable to restore host device labelling on hotplug fail");
> +        if (teardowndevice &&
> +            qemuDomainNamespaceTeardownHostdev(vm, hostdev) < 0)
> +            VIR_WARN("Unable to remove host device from /dev");
> +        if (added)
> +            qemuHostdevReAttachMediatedDevices(driver,
> +                                               vm->def->name,
> +                                               vm->def->hostdevs,
> +                                               vm->def->nhostdevs);

All of them?!?

> +        qemuDomainReleaseDeviceAddress(vm, hostdev->info, NULL);
> +    }
> +    VIR_FREE(devstr);
> +    return ret;
> +}
> +
> +
>  int
>  qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
>                             virDomainObjPtr vm,
> @@ -2602,6 +2684,10 @@ qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
>          if (qemuDomainAttachSCSIVHostDevice(driver, vm, hostdev) < 0)
>              goto error;
>          break;
> +    case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV:
> +        if (qemuDomainAttachMediatedDevice(driver, vm, hostdev) < 0)
> +            goto error;
> +        break;
>  
>      default:
>          virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> -- 
> 2.14.3
> 
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