conf: Introduce new <hostdev> attribute 'display'

QEMU 2.12 introduced a new type of display for mediated devices using vfio-pci backend which allows a mediated device to be used as a VGA compatible device as an alternative to an emulated video device. QEMU exposes this feature via a vfio device property 'display' with supported values 'on/off/auto' (libvirt will default to 'off'). This patch adds the necessary bits to domain config handling in order to expose this feature. Since there's no convenient way for libvirt to come up with usable defaults for the display setting, simply because libvirt is not able to figure out which of the display implementations - dma-buf which requires OpenGL support vs vfio regions which doesn't need OpenGL (works with OpenGL enabled too) - the underlying mdev uses. Reviewed-by: Ján Tomko <jtomko@redhat.com> Signed-off-by: Erik Skultety <eskultet@redhat.com>
2024-12-22 13:45:38 +00:00 · 2018-05-24 16:04:26 +02:00 · 2018-05-24 16:04:26 +02:00 · d54e45b6ed
commit d54e45b6ed
parent f1f6f48582
8 changed files with 222 additions and 8 deletions
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@ -4532,9 +4532,23 @@
          guest. Currently, <code>model='vfio-pci'</code> and
          <code>model='vfio-ccw'</code> (<span class="since">Since 4.4.0</span>)
          is supported. Refer <a href="drvnodedev.html#MDEV">MDEV</a> to create
-          a mediated device on the host. There are also some implications on the
-          usage of guest's address type depending on the <code>model</code>
-          attribute, see the <code>address</code> element below.
+          a mediated device on the host.
+          <span class="since">Since 4.6.0 (QEMU 2.12)</span> an optional
+          <code>display</code> attribute may be used to enable or disable
+          support for an accelerated remote desktop backed by a mediated
+          device (such as NVIDIA vGPU or Intel GVT-g) as an alternative to
+          emulated <a href="#elementsVideo">video devices</a>. This attribute
+          is limited to <code>model='vfio-pci'</code> only. Supported values
+          are either <code>on</code> or <code>off</code> (default is 'off').
+          It is required to use a
+          <a href="#elementsGraphics">graphical framebuffer</a> in order to
+          use this attribute, currently only supported with VNC, Spice and
+          egl-headless graphics devices.
+          <p>
+            Note: There are also some implications on the usage of guest's
+            address type depending on the <code>model</code> attribute,
+            see the <code>address</code> element below.
+          </p>
          </dd>
        </dl>
        <p>
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@ -4579,6 +4579,11 @@
        <value>vfio-ccw</value>
      </choice>
    </attribute>
+    <optional>
+      <attribute name="display">
+        <ref name="virOnOff"/>
+      </attribute>
+    </optional>
    <element name="source">
      <ref name="mdevaddress"/>
    </element>
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@ -7646,6 +7646,7 @@ virDomainHostdevDefParseXMLSubsys(xmlNodePtr node,
    char *rawio = NULL;
    char *backendStr = NULL;
    char *model = NULL;
+    char *display = NULL;
    int backend;
    int ret = -1;
    virDomainHostdevSubsysPCIPtr pcisrc = &def->source.subsys.u.pci;
@ -7665,6 +7666,7 @@ virDomainHostdevDefParseXMLSubsys(xmlNodePtr node,
    sgio = virXMLPropString(node, "sgio");
    rawio = virXMLPropString(node, "rawio");
    model = virXMLPropString(node, "model");
+    display = virXMLPropString(node, "display");

    /* @type is passed in from the caller rather than read from the
     * xml document, because it is specified in different places for
@ -7752,6 +7754,15 @@ virDomainHostdevDefParseXMLSubsys(xmlNodePtr node,
                           model);
            goto cleanup;
        }
+
+        if (display &&
+            (mdevsrc->display = virTristateSwitchTypeFromString(display)) <= 0) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("unknown value '%s' for <hostdev> attribute "
+                             "'display'"),
+                           display);
+            goto cleanup;
+        }
    }

    switch (def->source.subsys.type) {
@ -7805,6 +7816,7 @@ virDomainHostdevDefParseXMLSubsys(xmlNodePtr node,
    VIR_FREE(rawio);
    VIR_FREE(backendStr);
    VIR_FREE(model);
+    VIR_FREE(display);
    return ret;
 }

@ -26558,9 +26570,14 @@ virDomainHostdevDefFormat(virBufferPtr buf,
                              virTristateBoolTypeToString(scsisrc->rawio));
        }

-        if (def->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV)
+        if (def->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV) {
            virBufferAsprintf(buf, " model='%s'",
                              virMediatedDeviceModelTypeToString(mdevsrc->model));
+            if (mdevsrc->display != VIR_TRISTATE_SWITCH_ABSENT)
+                virBufferAsprintf(buf, " display='%s'",
+                                  virTristateSwitchTypeToString(mdevsrc->display));
+        }
+
    }
    virBufferAddLit(buf, ">\n");
    virBufferAdjustIndent(buf, 2);
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@ -382,6 +382,7 @@ typedef struct _virDomainHostdevSubsysMediatedDev virDomainHostdevSubsysMediated
 typedef virDomainHostdevSubsysMediatedDev *virDomainHostdevSubsysMediatedDevPtr;
 struct _virDomainHostdevSubsysMediatedDev {
    int model;                          /* enum virMediatedDeviceModelType */
+    int display; /* virTristateSwitch */
    char uuidstr[VIR_UUID_STRING_BUFLEN];   /* mediated device's uuid string */
 };

--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@ -4451,9 +4451,48 @@ qemuDomainDeviceDefValidateNetwork(const virDomainNetDef *net)


 static int
-qemuDomainDeviceDefValidateHostdev(const virDomainHostdevDef *hostdev,
-                                   const virDomainDef *def)
+qemuDomainMdevDefValidate(const virDomainHostdevSubsysMediatedDev *mdevsrc,
+                          const virDomainDef *def,
+                          virQEMUCapsPtr qemuCaps)
 {
+    if (mdevsrc->display == VIR_TRISTATE_SWITCH_ABSENT)
+        return 0;
+
+    if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VFIO_PCI_DISPLAY)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("display property of device vfio-pci is "
+                         "not supported by this version of QEMU"));
+        return -1;
+    }
+
+    if (mdevsrc->model != VIR_MDEV_MODEL_TYPE_VFIO_PCI) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("<hostdev> attribute 'display' is only supported"
+                         " with model='vfio-pci'"));
+
+        return -1;
+    }
+
+    if (mdevsrc->display == VIR_TRISTATE_SWITCH_ON) {
+        if (def->ngraphics == 0) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("graphics device is needed for attribute value "
+                             "'display=on' in <hostdev>"));
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+
+static int
+qemuDomainDeviceDefValidateHostdev(const virDomainHostdevDef *hostdev,
+                                   const virDomainDef *def,
+                                   virQEMUCapsPtr qemuCaps)
+{
+    const virDomainHostdevSubsysMediatedDev *mdevsrc;
+
    /* forbid capabilities mode hostdev in this kind of hypervisor */
    if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_CAPABILITIES) {
        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@ -4463,6 +4502,24 @@ qemuDomainDeviceDefValidateHostdev(const virDomainHostdevDef *hostdev,
        return -1;
    }

+    if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS) {
+        switch ((virDomainHostdevSubsysType) hostdev->source.subsys.type) {
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB:
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI:
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI:
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI_HOST:
+            break;
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV:
+            mdevsrc = &hostdev->source.subsys.u.mdev;
+            return qemuDomainMdevDefValidate(mdevsrc, def, qemuCaps);
+        case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_LAST:
+        default:
+            virReportEnumRangeError(virDomainHostdevSubsysType,
+                                    hostdev->source.subsys.type);
+            return -1;
+        }
+    }
+
    return 0;
 }

@ -5621,7 +5678,8 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
        break;

    case VIR_DOMAIN_DEVICE_HOSTDEV:
-        ret = qemuDomainDeviceDefValidateHostdev(dev->data.hostdev, def);
+        ret = qemuDomainDeviceDefValidateHostdev(dev->data.hostdev, def,
+                                                 qemuCaps);
        break;

    case VIR_DOMAIN_DEVICE_VIDEO:
@ -6231,6 +6289,35 @@ qemuDomainVsockDefPostParse(virDomainVsockDefPtr vsock)
 }


+static int
+qemuDomainHostdevDefMdevPostParse(virDomainHostdevSubsysMediatedDevPtr mdevsrc,
+                                  virQEMUCapsPtr qemuCaps)
+{
+    /* QEMU 2.12 added support for vfio-pci display type, we default to
+     * 'display=off' to stay safe from future changes */
+    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_VFIO_PCI_DISPLAY) &&
+        mdevsrc->display == VIR_TRISTATE_SWITCH_ABSENT)
+        mdevsrc->display = VIR_TRISTATE_SWITCH_OFF;
+
+    return 0;
+}
+
+
+static int
+qemuDomainHostdevDefPostParse(virDomainHostdevDefPtr hostdev,
+                              virQEMUCapsPtr qemuCaps)
+{
+    virDomainHostdevSubsysPtr subsys = &hostdev->source.subsys;
+
+    if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
+        hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV &&
+        qemuDomainHostdevDefMdevPostParse(&subsys->u.mdev, qemuCaps) < 0)
+        return -1;
+
+    return 0;
+}
+
+
 static int
 qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
                             const virDomainDef *def,
@ -6281,11 +6368,14 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
        ret = qemuDomainVsockDefPostParse(dev->data.vsock);
        break;

+    case VIR_DOMAIN_DEVICE_HOSTDEV:
+        ret = qemuDomainHostdevDefPostParse(dev->data.hostdev, qemuCaps);
+        break;
+
    case VIR_DOMAIN_DEVICE_LEASE:
    case VIR_DOMAIN_DEVICE_FS:
    case VIR_DOMAIN_DEVICE_INPUT:
    case VIR_DOMAIN_DEVICE_SOUND:
-    case VIR_DOMAIN_DEVICE_HOSTDEV:
    case VIR_DOMAIN_DEVICE_WATCHDOG:
    case VIR_DOMAIN_DEVICE_GRAPHICS:
    case VIR_DOMAIN_DEVICE_HUB:
--- a/tests/qemuxml2argvdata/hostdev-mdev-display.xml
+++ b/tests/qemuxml2argvdata/hostdev-mdev-display.xml
@ -0,0 +1,39 @@
+<domain type='qemu'>
+  <name>QEMUGuest2</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest2'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='ide' index='0'>
+    </controller>
+    <graphics type='vnc'/>
+    <hostdev mode='subsystem' type='mdev' model='vfio-pci' display='on'>
+      <source>
+        <address uuid='53764d0e-85a0-42b4-af5c-2046b460b1dc'/>
+      </source>
+    </hostdev>
+    <video>
+      <model type='qxl' heads='1'/>
+    </video>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmloutdata/hostdev-mdev-display.xml
+++ b/tests/qemuxml2xmloutdata/hostdev-mdev-display.xml
@ -0,0 +1,47 @@
+<domain type='qemu'>
+  <name>QEMUGuest2</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest2'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='ide' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+    </controller>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <graphics type='vnc' port='-1' autoport='yes'>
+      <listen type='address'/>
+    </graphics>
+    <video>
+      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </video>
+    <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-pci' display='on'>
+      <source>
+        <address uuid='53764d0e-85a0-42b4-af5c-2046b460b1dc'/>
+      </source>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+    </hostdev>
+    <memballoon model='none'/>
+  </devices>
+</domain>
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@ -477,6 +477,7 @@ mymain(void)
    DO_TEST("hostdev-pci-address", NONE);
    DO_TEST("hostdev-vfio", NONE);
    DO_TEST("hostdev-mdev-precreated", NONE);
+    DO_TEST("hostdev-mdev-display", QEMU_CAPS_VFIO_PCI_DISPLAY);
    DO_TEST("pci-rom", NONE);
    DO_TEST("pci-rom-disabled", NONE);
    DO_TEST("pci-rom-disabled-invalid", NONE);