conf: allow display and ramfb for vfio pci hostdevs

We already allow the user to specify display="on" and ramfb="on" for
mdev host devices. But newer GPU models will no longer use the mdev
framework, so we should enable this same functionality for other
non-mdev passthrough PCI devices.

Resolves: https://issues.redhat.com/browse/RHEL-28808

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

docs/formatdomain.rst

@@ -4390,6 +4390,14 @@ or:
       starting the guest or hot-plugging the device and
       ``virNodeDeviceReAttach`` (or ``virsh nodedev-reattach``) after hot-unplug
       or stopping the guest.
+      :since:`Since 10.3.0` an optional ``display`` attribute may be used to
+      enable using a vgpu device as a display device for the guest. Supported
+      values are either ``on`` or ``off`` (default). There is also an optional
+      ``ramfb`` attribute with values of either ``on`` or ``off`` (default).
+      When enabled, the ``ramfb`` attribute provides a memory framebuffer device
+      to the guest. This framebuffer allows the vgpu to be used as a boot display
+      before the gpu driver is loaded within the guest. ``ramfb`` requires the
+      ``display`` attribute to be set to ``on``.
    ``scsi``
       For SCSI devices, user is responsible to make sure the device is not used
       by host. If supported by the hypervisor and OS, the optional ``sgio`` (

src/conf/domain_conf.c

@@ -6306,6 +6306,16 @@ virDomainHostdevDefParseXMLSubsys(xmlNodePtr node,
                                      VIR_XML_PROP_NONE,
                                      &mdevsrc->ramfb) < 0)
             return -1;
+    } else if (def->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) {
+        if (virXMLPropTristateSwitch(node, "display",
+                                     VIR_XML_PROP_NONE,
+                                     &pcisrc->display) < 0)
+            return -1;
+
+        if (virXMLPropTristateSwitch(node, "ramfb",
+                                     VIR_XML_PROP_NONE,
+                                     &pcisrc->ramfb) < 0)
+            return -1;
     }
 
     switch (def->source.subsys.type) {
@@ -26251,6 +26261,7 @@ virDomainHostdevDefFormat(virBuffer *buf,
     const char *mode = virDomainHostdevModeTypeToString(def->mode);
     virDomainHostdevSubsysSCSI *scsisrc = &def->source.subsys.u.scsi;
     virDomainHostdevSubsysMediatedDev *mdevsrc = &def->source.subsys.u.mdev;
+    virDomainHostdevSubsysPCI *pcisrc = &def->source.subsys.u.pci;
     virDomainHostdevSubsysSCSIVHost *scsihostsrc = &def->source.subsys.u.scsi_host;
     const char *type;
 
@@ -26319,7 +26330,14 @@ virDomainHostdevDefFormat(virBuffer *buf,
                 virBufferAsprintf(buf, " ramfb='%s'",
                                   virTristateSwitchTypeToString(mdevsrc->ramfb));
         }
-
+        if (def->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) {
+            if (pcisrc->display != VIR_TRISTATE_SWITCH_ABSENT)
+                virBufferAsprintf(buf, " display='%s'",
+                                  virTristateSwitchTypeToString(pcisrc->display));
+            if (pcisrc->ramfb != VIR_TRISTATE_SWITCH_ABSENT)
+                virBufferAsprintf(buf, " ramfb='%s'",
+                                  virTristateSwitchTypeToString(pcisrc->ramfb));
+        }
     }
     virBufferAddLit(buf, ">\n");
     virBufferAdjustIndent(buf, 2);

src/conf/domain_conf.h

@@ -236,6 +236,8 @@ struct _virDomainHostdevSubsysUSB {
 struct _virDomainHostdevSubsysPCI {
     virPCIDeviceAddress addr; /* host address */
     virDeviceHostdevPCIDriverInfo driver;
+    virTristateSwitch display;
+    virTristateSwitch ramfb;
 
     virBitmap *origstates;
 };

src/conf/domain_validate.c

@@ -1291,15 +1291,20 @@ virDomainDefHostdevValidate(const virDomainDef *def)
             }
         }
 
-        if (dev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
-            dev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV &&
-            dev->source.subsys.u.mdev.ramfb == VIR_TRISTATE_SWITCH_ON) {
-            if (ramfbEnabled) {
-                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                               _("Only one vgpu device can have 'ramfb' enabled"));
-                return -1;
+        if (dev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS) {
+            virTristateSwitch *ramfbsetting = NULL;
+            if (dev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV)
+                ramfbsetting = &dev->source.subsys.u.mdev.ramfb;
+            else if (dev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI)
+                ramfbsetting = &dev->source.subsys.u.pci.ramfb;
+            if (ramfbsetting && *ramfbsetting == VIR_TRISTATE_SWITCH_ON) {
+                if (ramfbEnabled) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                        _("Only one vgpu device can have 'ramfb' enabled"));
+                    return -1;
+                }
+                ramfbEnabled = true;
             }
-            ramfbEnabled = true;
         }
     }
 

src/conf/schemas/domaincommon.rng

@@ -6267,6 +6267,7 @@
           <ref name="pciaddress"/>
         </element>
       </element>
+      <ref name="hostdevsubsysvfiodisplay"/>
     </interleave>
   </define>
 
@@ -6386,6 +6387,19 @@
     </element>
   </define>
 
+  <define name="hostdevsubsysvfiodisplay">
+    <optional>
+      <attribute name="ramfb">
+        <ref name="virOnOff"/>
+      </attribute>
+    </optional>
+    <optional>
+      <attribute name="display">
+        <ref name="virOnOff"/>
+      </attribute>
+    </optional>
+  </define>
+
   <define name="hostdevsubsysmdev">
     <attribute name="type">
       <value>mdev</value>
@@ -6397,16 +6411,7 @@
         <value>vfio-ap</value>
       </choice>
     </attribute>
-    <optional>
-      <attribute name="ramfb">
-        <ref name="virOnOff"/>
-      </attribute>
-    </optional>
-    <optional>
-      <attribute name="display">
-        <ref name="virOnOff"/>
-      </attribute>
-    </optional>
+    <ref name="hostdevsubsysvfiodisplay"/>
     <element name="source">
       <ref name="mdevaddress"/>
     </element>