conf: qemu: add virtiofs fsdriver type

Introduce a new 'virtiofs' driver type for filesystem.

<filesystem type='mount' accessmode='passthrough'>
  <driver type='virtiofs'/>
  <source dir='/path'/>
  <target dir='mount_tag'>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</filesystem>
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>
Tested-by: NAndrea Bolognani <abologna@redhat.com>

docs/formatdomain.html.in

@@ -3945,6 +3945,11 @@
     <target dir='/import/from/host'/>
     <readonly/>
   </filesystem>
+  <filesystem type='mount' accessmode='passthrough'>
+      <driver type='virtiofs'/>
+      <source dir='/path'/>
+      <target dir='mount_tag'/>
+  </filesystem>
   ...
 </devices>
 ...</pre>
@@ -3973,6 +3978,9 @@
         while the value <code>immediate</code> means that a host writeback
         is immediately triggered for all pages touched during a guest file
         write operation <span class="since">(since 0.9.10)</span>.
+        <span class="since">Since 6.2.0</span>, <code>type='virtiofs'</code>
+        is also supported. Using virtiofs requires setting up shared memory,
+        see the guide: <a href="kbase/virtiofs.html">Virtio-FS</a>
         </dd>
         <dt><code>template</code></dt>
         <dd>
@@ -4008,7 +4016,9 @@
       The filesystem element has an optional attribute <code>accessmode</code>
       which specifies the security mode for accessing the source
       <span class="since">(since 0.8.5)</span>. Currently this only works
-      with <code>type='mount'</code> for the QEMU/KVM driver. The possible
+      with <code>type='mount'</code> for the QEMU/KVM driver.
+      For driver type <code>virtiofs</code>, only <code>passthrough</code> is
+      supported. For other driver types, the possible
       values are:
 
         <dl>

docs/schemas/domaincommon.rng

@@ -2645,6 +2645,12 @@
           </optional>
           <ref name='virtioOptions'/>
         </group>
+        <group>
+          <attribute name="type">
+            <value>virtiofs</value>
+          </attribute>
+          <ref name='virtioOptions'/>
+        </group>
         <empty/>
       </choice>
     </element>

src/conf/domain_conf.c

@@ -477,6 +477,7 @@ VIR_ENUM_IMPL(virDomainFSDriver,
               "loop",
               "nbd",
               "ploop",
+              "virtiofs",
 );
 
 VIR_ENUM_IMPL(virDomainFSAccessMode,

src/conf/domain_conf.h

@@ -774,6 +774,7 @@ typedef enum {
     VIR_DOMAIN_FS_DRIVER_TYPE_LOOP,
     VIR_DOMAIN_FS_DRIVER_TYPE_NBD,
     VIR_DOMAIN_FS_DRIVER_TYPE_PLOOP,
+    VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS,
 
     VIR_DOMAIN_FS_DRIVER_TYPE_LAST
 } virDomainFSDriverType;

src/qemu/qemu_command.c

@@ -2681,6 +2681,10 @@ qemuBuildFilesystemCommandLine(virCommandPtr cmd,
                 return -1;
             break;
 
+        case VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS:
+            /* TODO: vhost-user-fs-pci */
+            break;
+
         case VIR_DOMAIN_FS_DRIVER_TYPE_LOOP:
         case VIR_DOMAIN_FS_DRIVER_TYPE_NBD:
         case VIR_DOMAIN_FS_DRIVER_TYPE_PLOOP:

src/qemu/qemu_domain.c

@@ -8302,6 +8302,10 @@ qemuDomainDeviceDefValidateFS(virDomainFSDefPtr fs,
                        _("Filesystem driver type not supported"));
         return -1;
 
+    case VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS:
+        /* TODO: vhost-user-fs-pci */
+        return 0;
+
     case VIR_DOMAIN_FS_DRIVER_TYPE_LAST:
     default:
         virReportEnumRangeError(virDomainFSDriverType, fs->fsdriver);

src/qemu/qemu_domain_address.c

@@ -699,6 +699,10 @@ qemuDomainDeviceCalculatePCIConnectFlags(virDomainDeviceDefPtr dev,
             }
             break;
 
+        case VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS:
+            /* vhost-user-fs-pci */
+            return virtioFlags;
+
         case VIR_DOMAIN_FS_DRIVER_TYPE_LOOP:
         case VIR_DOMAIN_FS_DRIVER_TYPE_NBD:
         case VIR_DOMAIN_FS_DRIVER_TYPE_PLOOP:

tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml

+<domain type='kvm'>
+  <name>guest</name>
+  <uuid>126f2720-6f8e-45ab-a886-ec9277079a67</uuid>
+  <memory unit='KiB'>14680064</memory>
+  <currentMemory unit='KiB'>14680064</currentMemory>
+  <memoryBacking>
+    <source type='file'/>
+    <access mode='shared'/>
+  </memoryBacking>
+  <vcpu placement='static'>2</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu mode='custom' match='exact' check='none'>
+    <model fallback='forbid'>qemu64</model>
+    <numa>
+      <cell id='0' cpus='0-1' memory='14680064' unit='KiB' memAccess='shared'/>
+    </numa>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0' model='none'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <filesystem type='mount' accessmode='passthrough'>
+      <driver type='virtiofs'/>
+      <source dir='/path'/>
+      <target dir='mount_tag'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </filesystem>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2argvdata/vhost-user-fs-hugepages.xml

+<domain type='qemu'>
+  <name>guest</name>
+  <uuid>1ccfd97d-5eb4-478a-bbe6-88d254c16db7</uuid>
+  <memory unit='KiB'>4194304</memory>
+  <currentMemory unit='KiB'>4194304</currentMemory>
+  <memoryBacking>
+    <hugepages>
+      <page size='2048' unit='KiB'/>
+    </hugepages>
+    <access mode='shared'/>
+  </memoryBacking>
+  <vcpu placement='static'>2</vcpu>
+  <os>
+    <type arch='x86_64' machine='q35'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+    <apic/>
+  </features>
+  <cpu mode='custom' match='exact' check='none'>
+    <model fallback='forbid'>qemu64</model>
+    <numa>
+      <cell id='0' cpus='0-1' memory='2097152' unit='KiB' memAccess='shared'/>
+    </numa>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='qcow2'/>
+      <source file='/var/lib/libvirt/images/guest.qcow2'/>
+      <target dev='vda' bus='virtio'/>
+      <address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
+    </disk>
+    <controller type='usb' index='0' model='none'/>
+    <controller type='sata' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pcie-root'/>
+    <controller type='pci' index='1' model='pcie-root-port'>
+      <model name='pcie-root-port'/>
+      <target chassis='1' port='0x8'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0' multifunction='on'/>
+    </controller>
+    <controller type='pci' index='2' model='pcie-root-port'>
+      <model name='pcie-root-port'/>
+      <target chassis='2' port='0x9'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+    </controller>
+    <controller type='pci' index='3' model='pcie-root-port'>
+      <model name='pcie-root-port'/>
+      <target chassis='3' port='0xa'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='4' model='pcie-root-port'>
+      <model name='pcie-root-port'/>
+      <target chassis='4' port='0xb'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x3'/>
+    </controller>
+    <filesystem type='mount' accessmode='passthrough'>
+      <driver type='virtiofs'/>
+      <source dir='/path'/>
+      <target dir='mount_tag'/>
+      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
+    </filesystem>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2xmloutdata/vhost-user-fs-fd-memory.x86_64-latest.xml

+../qemuxml2argvdata/vhost-user-fs-fd-memory.xml
\ No newline at end of file

tests/qemuxml2xmloutdata/vhost-user-fs-hugepages.x86_64-latest.xml

+../qemuxml2argvdata/vhost-user-fs-hugepages.xml
\ No newline at end of file

tests/qemuxml2xmltest.c

@@ -1434,6 +1434,9 @@ mymain(void)
     DO_TEST("vhost-vsock-ccw-auto", QEMU_CAPS_DEVICE_VHOST_VSOCK,
             QEMU_CAPS_CCW);
 
+    DO_TEST_CAPS_LATEST("vhost-user-fs-fd-memory");
+    DO_TEST_CAPS_LATEST("vhost-user-fs-hugepages");
+
     DO_TEST("riscv64-virt",
             QEMU_CAPS_DEVICE_VIRTIO_MMIO);
     DO_TEST("riscv64-virt-pci",