qemu: build vhost-user-fs device command line

Format the 'vhost-user-fs' device on the QEMU command line.

This device provides shared file system access using the FUSE protocol
carried over virtio.
The actual file server is implemented in an external vhost-user-fs device
backend process.

https://bugzilla.redhat.com/show_bug.cgi?id=1694166

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Tested-by: Andrea Bolognani <abologna@redhat.com>

src/qemu/qemu_command.c

@@ -2575,6 +2575,46 @@ qemuBuildDisksCommandLine(virCommandPtr cmd,
 }
 
 
+static int
+qemuBuildVHostUserFsCommandLine(virCommandPtr cmd,
+                                virDomainFSDef *fs,
+                                const virDomainDef *def,
+                                qemuDomainObjPrivatePtr priv)
+{
+    g_autofree char *chardev_alias = NULL;
+    g_auto(virBuffer) opt = VIR_BUFFER_INITIALIZER;
+
+    chardev_alias = g_strdup_printf("chr-vu-%s", fs->info.alias);
+
+    virCommandAddArg(cmd, "-chardev");
+    virBufferAddLit(&opt, "socket");
+    virBufferAsprintf(&opt, ",id=%s", chardev_alias);
+    virBufferAddLit(&opt, ",path=");
+    virQEMUBuildBufferEscapeComma(&opt, QEMU_DOMAIN_FS_PRIVATE(fs)->vhostuser_fs_sock);
+    virCommandAddArgBuffer(cmd, &opt);
+
+    virCommandAddArg(cmd, "-device");
+
+    if (qemuBuildVirtioDevStr(&opt, "vhost-user-fs", priv->qemuCaps,
+                              VIR_DOMAIN_DEVICE_FS, fs) < 0)
+        return -1;
+
+    virBufferAsprintf(&opt, ",chardev=%s", chardev_alias);
+    if (fs->queue_size)
+        virBufferAsprintf(&opt, ",queue-size=%llu", fs->queue_size);
+    virBufferAddLit(&opt, ",tag=");
+    virQEMUBuildBufferEscapeComma(&opt, fs->dst);
+    if (qemuBuildVirtioOptionsStr(&opt, fs->virtio, priv->qemuCaps) < 0)
+        return -1;
+
+    if (qemuBuildDeviceAddressStr(&opt, def, &fs->info, priv->qemuCaps) < 0)
+        return -1;
+
+    virCommandAddArgBuffer(cmd, &opt);
+    return 0;
+}
+
+
 static char *
 qemuBuildFSStr(virDomainFSDefPtr fs)
 {
@@ -2667,7 +2707,7 @@ static int
 qemuBuildFilesystemCommandLine(virCommandPtr cmd,
                                const virDomainDef *def,
                                virQEMUCapsPtr qemuCaps,
-                               qemuDomainObjPrivatePtr priv G_GNUC_UNUSED)
+                               qemuDomainObjPrivatePtr priv)
 {
     size_t i;
 
@@ -2682,7 +2722,9 @@ qemuBuildFilesystemCommandLine(virCommandPtr cmd,
             break;
 
         case VIR_DOMAIN_FS_DRIVER_TYPE_VIRTIOFS:
-            /* TODO: vhost-user-fs-pci */
+            /* vhost-user-fs-pci */
+            if (qemuBuildVHostUserFsCommandLine(cmd, def->fss[i], def, priv) < 0)
+                return -1;
             break;
 
         case VIR_DOMAIN_FS_DRIVER_TYPE_LOOP:

tests/qemuxml2argvdata/vhost-user-fs-fd-memory.x86_64-latest.args

@@ -0,0 +1,39 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/tmp/lib/domain--1-guest \
+USER=test \
+LOGNAME=test \
+XDG_DATA_HOME=/tmp/lib/domain--1-guest/.local/share \
+XDG_CACHE_HOME=/tmp/lib/domain--1-guest/.cache \
+XDG_CONFIG_HOME=/tmp/lib/domain--1-guest/.config \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name guest=guest,debug-threads=on \
+-S \
+-object secret,id=masterKey0,format=raw,\
+file=/tmp/lib/domain--1-guest/master-key.aes \
+-machine pc,accel=kvm,usb=off,dump-guest-core=off \
+-cpu qemu64 \
+-m 14336 \
+-overcommit mem-lock=off \
+-smp 2,sockets=2,cores=1,threads=1 \
+-object memory-backend-file,id=ram-node0,\
+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-guest/ram-node0,share=yes,\
+size=15032385536 \
+-numa node,nodeid=0,cpus=0-1,memdev=ram-node0 \
+-uuid 126f2720-6f8e-45ab-a886-ec9277079a67 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-no-acpi \
+-boot strict=on \
+-chardev socket,id=chr-vu-fs0,path=/tmp/lib/domain--1-guest/fs0.vhost-fs.sock \
+-device vhost-user-fs-pci,chardev=chr-vu-fs0,queue-size=1024,tag=mount_tag,\
+bus=pci.0,addr=0x2 \
+-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
+resourcecontrol=deny \
+-msg timestamp=on

tests/qemuxml2argvdata/vhost-user-fs-hugepages.x86_64-latest.args

@@ -0,0 +1,47 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/tmp/lib/domain--1-guest \
+USER=test \
+LOGNAME=test \
+XDG_DATA_HOME=/tmp/lib/domain--1-guest/.local/share \
+XDG_CACHE_HOME=/tmp/lib/domain--1-guest/.cache \
+XDG_CONFIG_HOME=/tmp/lib/domain--1-guest/.config \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name guest=guest,debug-threads=on \
+-S \
+-object secret,id=masterKey0,format=raw,\
+file=/tmp/lib/domain--1-guest/master-key.aes \
+-machine q35,accel=tcg,usb=off,dump-guest-core=off \
+-cpu qemu64 \
+-m 2048 \
+-overcommit mem-lock=off \
+-smp 2,sockets=2,cores=1,threads=1 \
+-object memory-backend-file,id=ram-node0,prealloc=yes,\
+mem-path=/dev/hugepages2M/libvirt/qemu/-1-guest,share=yes,size=2147483648 \
+-numa node,nodeid=0,cpus=0-1,memdev=ram-node0 \
+-uuid 1ccfd97d-5eb4-478a-bbe6-88d254c16db7 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-boot strict=on \
+-device pcie-root-port,port=0x8,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,\
+addr=0x1 \
+-device pcie-root-port,port=0x9,chassis=2,id=pci.2,bus=pcie.0,addr=0x1.0x1 \
+-device pcie-root-port,port=0xa,chassis=3,id=pci.3,bus=pcie.0,addr=0x1.0x2 \
+-device pcie-root-port,port=0xb,chassis=4,id=pci.4,bus=pcie.0,addr=0x1.0x3 \
+-blockdev '{"driver":"file","filename":"/var/lib/libvirt/images/guest.qcow2",\
+"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
+-blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2",\
+"file":"libvirt-1-storage"}' \
+-device virtio-blk-pci,scsi=off,bus=pci.4,addr=0x0,drive=libvirt-1-format,\
+id=virtio-disk0,bootindex=1 \
+-chardev socket,id=chr-vu-fs0,path=/tmp/lib/domain--1-guest/fs0.vhost-fs.sock \
+-device vhost-user-fs-pci,chardev=chr-vu-fs0,tag=mount_tag,bus=pci.1,addr=0x0 \
+-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
+resourcecontrol=deny \
+-msg timestamp=on

tests/qemuxml2argvtest.c

@@ -3061,6 +3061,9 @@ mymain(void)
 
     DO_TEST_CAPS_VER("launch-security-sev", "2.12.0");
 
+    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",