Explicitly format the isa-fdc controller for newer q35 machines

Since QEMU commit ea96bc6 [1]:
i386: drop FDC in pc-q35-2.4+ if neither it nor floppy drives are wanted
the floppy controller is no longer implicit.

Specify it explicitly on the command line if the machine type version
is 2.4 or later.

Note that libvirt's floppy drives do not result in QEMU implying the
controller, because libvirt uses if=none instead of if=floppy.

https://bugzilla.redhat.com/show_bug.cgi?id=1227880

[1] http://git.qemu.org/?p=qemu.git;a=commitdiff;h=ea96bc6

src/qemu/qemu_command.c

@@ -8816,9 +8816,9 @@ qemuBuildCommandLine(virConnectPtr conn,
          * List of controller types that we add commandline args for,
          * *in the order we want to add them*.
          *
-         * We don't add an explicit FD controller because the
+         * The floppy controller is implicit on PIIX4 and older Q35
-         * provided PIIX4 device already includes one. It isn't possible to
+         * machines. For newer Q35 machines it is added out of the
-         * remove the PIIX4.
+         * controllers loop, after the floppy drives.
          *
          * We don't add PCI/PCIe root controller either, because it's
          * implicit, but we do add PCI bridges and other PCI
@@ -8839,6 +8839,8 @@ qemuBuildCommandLine(virConnectPtr conn,
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virBuffer boot_buf = VIR_BUFFER_INITIALIZER;
     char *boot_order_str = NULL, *boot_opts_str = NULL;
+    virBuffer fdc_opts = VIR_BUFFER_INITIALIZER;
+    char *fdc_opts_str = NULL;
 
     VIR_DEBUG("conn=%p driver=%p def=%p mon=%p json=%d "
               "qemuCaps=%p migrateFrom=%s migrateFD=%d "
@@ -9789,8 +9791,12 @@ qemuBuildCommandLine(virConnectPtr conn,
                                     disk->info.alias) < 0)
                         goto error;
 
-                    virCommandAddArg(cmd, "-global");
+                    if (!qemuDomainMachineNeedsFDC(def)) {
-                    virCommandAddArgFormat(cmd, "isa-fdc.%s", optstr);
+                        virCommandAddArg(cmd, "-global");
+                        virCommandAddArgFormat(cmd, "isa-fdc.%s", optstr);
+                    } else {
+                        virBufferAsprintf(&fdc_opts, "%s,", optstr);
+                    }
                     VIR_FREE(optstr);
 
                     if (bootindex) {
@@ -9800,8 +9806,12 @@ qemuBuildCommandLine(virConnectPtr conn,
                                         bootindex) < 0)
                             goto error;
 
-                        virCommandAddArg(cmd, "-global");
+                        if (!qemuDomainMachineNeedsFDC(def)) {
-                        virCommandAddArgFormat(cmd, "isa-fdc.%s", optstr);
+                            virCommandAddArg(cmd, "-global");
+                            virCommandAddArgFormat(cmd, "isa-fdc.%s", optstr);
+                        } else {
+                            virBufferAsprintf(&fdc_opts, "%s,", optstr);
+                        }
                         VIR_FREE(optstr);
                     }
                 } else {
@@ -9815,6 +9825,13 @@ qemuBuildCommandLine(virConnectPtr conn,
                 }
             }
         }
+        /* Newer Q35 machine types require an explicit FDC controller */
+        virBufferTrim(&fdc_opts, ",", -1);
+        if ((fdc_opts_str = virBufferContentAndReset(&fdc_opts))) {
+            virCommandAddArg(cmd, "-device");
+            virCommandAddArgFormat(cmd, "isa-fdc,%s", fdc_opts_str);
+            VIR_FREE(fdc_opts_str);
+        }
     } else {
         for (i = 0; i < def->ndisks; i++) {
             char dev[NAME_MAX];

src/qemu/qemu_domain.c

@@ -3245,6 +3245,25 @@ qemuDomainMachineIsI440FX(const virDomainDef *def)
 }
 
 
+bool
+qemuDomainMachineNeedsFDC(const virDomainDef *def)
+{
+    char *p = STRSKIP(def->os.machine, "pc-q35-");
+
+    if (p) {
+        if (STRPREFIX(p, "1.") ||
+            STRPREFIX(p, "2.0") ||
+            STRPREFIX(p, "2.1") ||
+            STRPREFIX(p, "2.2") ||
+            STRPREFIX(p, "2.3"))
+            return false;
+        return true;
+    }
+    return false;
+}
+
+
+
 /**
  * qemuDomainUpdateCurrentMemorySize:
  *

src/qemu/qemu_domain.h

@@ -465,6 +465,7 @@ virDomainChrSourceDefPtr qemuFindAgentConfig(virDomainDefPtr def);
 
 bool qemuDomainMachineIsQ35(const virDomainDef *def);
 bool qemuDomainMachineIsI440FX(const virDomainDef *def);
+bool qemuDomainMachineNeedsFDC(const virDomainDef *def);
 
 int qemuDomainUpdateCurrentMemorySize(virQEMUDriverPtr driver,
                                       virDomainObjPtr vm);

tests/qemuxml2argvdata/qemuxml2argv-boot-floppy-q35.args

@@ -0,0 +1,12 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu -S \
+-M pc-q35-2.4 \
+-m 214 -smp 1 \
+-nographic -nodefaults \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi -boot a \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
+-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
+-drive file=/tmp/firmware.img,if=none,id=drive-fdc0-0-0 \
+-device isa-fdc,driveA=drive-fdc0-0-0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x3

tests/qemuxml2argvdata/qemuxml2argv-boot-floppy-q35.xml

@@ -0,0 +1,40 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-q35-2.4'>hvm</type>
+    <boot dev='fd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='file' device='floppy'>
+      <driver name='qemu' type='raw'/>
+      <source file='/tmp/firmware.img'/>
+      <target dev='fda' bus='fdc'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <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='dmi-to-pci-bridge'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x1e' function='0x0'/>
+    </controller>
+    <controller type='pci' index='2' model='pci-bridge'>
+      <address type='pci' domain='0x0000' bus='0x01' slot='0x01' function='0x0'/>
+    </controller>
+    <controller type='fdc' index='0'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x02' slot='0x03' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-bootindex-floppy-q35.args

@@ -0,0 +1,11 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
+/usr/bin/qemu -S -M pc-q35-2.4 \
+-m 214 -smp 1 \
+-nographic -nodefaults \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
+-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
+-drive file=/tmp/firmware.img,if=none,id=drive-fdc0-0-0 \
+-device isa-fdc,driveA=drive-fdc0-0-0,bootindexA=1 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x3

tests/qemuxml2argvdata/qemuxml2argv-bootindex-floppy-q35.xml

@@ -0,0 +1,40 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-q35-2.4'>hvm</type>
+    <boot dev='fd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='file' device='floppy'>
+      <driver name='qemu' type='raw'/>
+      <source file='/tmp/firmware.img'/>
+      <target dev='fda' bus='fdc'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <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='dmi-to-pci-bridge'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x1e' function='0x0'/>
+    </controller>
+    <controller type='pci' index='2' model='pci-bridge'>
+      <address type='pci' domain='0x0000' bus='0x01' slot='0x01' function='0x0'/>
+    </controller>
+    <controller type='fdc' index='0'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x02' slot='0x03' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -607,6 +607,15 @@ mymain(void)
     DO_TEST("boot-cdrom", NONE);
     DO_TEST("boot-network", NONE);
     DO_TEST("boot-floppy", NONE);
+    DO_TEST("boot-floppy-q35",
+            QEMU_CAPS_DEVICE, QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_DRIVE, QEMU_CAPS_ICH9_AHCI);
+    DO_TEST("bootindex-floppy-q35",
+            QEMU_CAPS_DEVICE, QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_DRIVE, QEMU_CAPS_ICH9_AHCI, QEMU_CAPS_BOOT_MENU,
+            QEMU_CAPS_BOOTINDEX);
     DO_TEST("boot-multi", QEMU_CAPS_BOOT_MENU);
     DO_TEST("boot-menu-enable",
             QEMU_CAPS_BOOT_MENU, QEMU_CAPS_DEVICE, QEMU_CAPS_DRIVE);