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>

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 43af599d78a2a082a380481134fa333780fc72cd..31aa6fb3f45246652ae06487139545c9cc517576 100644 (file)
--- 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>

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 157726752c768b81fab326fcecabe35638d41db9..be8430ab22b5f08a004f0caafa6e7bc1632bd4a6 100644 (file)
--- 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>

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 8deff5442fe9af14873d967fd56040f340502165..bd1dc0780db74f1027402a66866093de87743e5b 100644 (file)
--- 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);

diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 3deda1d978b6860b7376d25ba75c0be7794bc959..8ca9558ceb12be144c40fbb1034704d8f87d0e7b 100644 (file)
--- 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 */
 };
 

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index ce252b47eba9644dc0e6ae58e5e48b7a505561dc..c15089d3959a5338b8b22e086a2bb7ed4bc83a7e 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4450,10 +4450,49 @@ qemuDomainDeviceDefValidateNetwork(const virDomainNetDef *net)
 }
 
 
+static int
+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)
+                                   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:

diff --git a/tests/qemuxml2argvdata/hostdev-mdev-display.xml b/tests/qemuxml2argvdata/hostdev-mdev-display.xml
new file mode 100644 (file)
index 0000000..f37e08e
--- /dev/null
+++ 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>

diff --git a/tests/qemuxml2xmloutdata/hostdev-mdev-display.xml b/tests/qemuxml2xmloutdata/hostdev-mdev-display.xml
new file mode 100644 (file)
index 0000000..94c11b1
--- /dev/null
+++ 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>

diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 3527ccdec3dc9e8e487456d5d18952c19d6cf6e1..41e5ee9096f39c518395bc8e0a452c2d08d7c1a9 100644 (file)
--- 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);