[libvirt] [PATCHv3 1/2] qemu: enable using implicit sata controller in q35 machines

[Laine Stump]

q35 machines have an implicit ahci (sata) controller at 00:1F.2 which
has no "id" associated with it. For this reason, we can't refer to it
as "ahci0". Instead, we don't give an id on the commandline, which
qemu interprets as "use the first ahci controller". We then need to
specify the unit with "unit=%d" rather than adding it onto the bus
arg.
---
 src/qemu/qemu_command.c                         | 23 ++++++++++++++++++++---
 tests/qemuxml2argvdata/qemuxml2argv-q35.args    |  2 ++
 tests/qemuxml2argvdata/qemuxml2argv-q35.xml     |  5 +++++
 tests/qemuxml2argvtest.c                        |  2 +-
 tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml |  5 +++++
 5 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 22ffa79..3d670f9 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -4211,9 +4211,26 @@ qemuBuildDriveDevStr(virDomainDefPtr def,
             virBufferAddLit(&opt, "ide-drive");
         }
 
-        virBufferAsprintf(&opt, ",bus=ahci%d.%d",
-                          disk->info.addr.drive.controller,
-                          disk->info.addr.drive.unit);
+        if (qemuDomainMachineIsQ35(def) &&
+            disk->info.addr.drive.controller == 0) {
+            /* Q35 machines have an implicit ahci (sata) controller at
+             * 00:1F.2 which has no "id" associated with it. For this
+             * reason, we can't refer to it as "ahci0". Instead, we
+             * don't give an id, which qemu interprets as "use the
+             * first ahci controller". We then need to specify the
+             * unit with "unit=%d" rather than adding it onto the bus
+             * arg.
+             */
+            virBufferAsprintf(&opt, ",unit=%d", disk->info.addr.drive.unit);
+        } else {
+            /* All other ahci controllers have been created by
+             * libvirt, so they *do* have an id, and we can identify
+             * them that way.
+             */
+            virBufferAsprintf(&opt, ",bus=ahci%d.%d",
+                              disk->info.addr.drive.controller,
+                              disk->info.addr.drive.unit);
+        }
         break;
     case VIR_DOMAIN_DISK_BUS_VIRTIO:
         if (disk->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) {
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-q35.args b/tests/qemuxml2argvdata/qemuxml2argv-q35.args
index a0ec66e..6b30b4d 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-q35.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-q35.args
@@ -3,4 +3,6 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test \
 -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \
 -device pci-bridge,chassis_nr=1,id=pci.1,bus=pcie.0,addr=0x2 \
 -device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
+-drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-sata0-0-0 \
+-device ide-drive,unit=0,drive=drive-sata0-0-0,id=sata0-0-0 \
 -vga qxl -global qxl.ram_size=67108864 -global qxl.vram_size=18874368
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-q35.xml b/tests/qemuxml2argvdata/qemuxml2argv-q35.xml
index 3541b14..edaf6cb 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-q35.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-q35.xml
@@ -14,6 +14,11 @@
   <on_crash>destroy</on_crash>
   <devices>
     <emulator>/usr/libexec/qemu-kvm</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='sda' bus='sata'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
     <controller type='pci' index='0' model='pcie-root'/>
     <controller type='pci' index='1' model='dmi-to-pci-bridge'/>
     <controller type='pci' index='2' model='pci-bridge'/>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 0068d27..679124e 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1001,7 +1001,7 @@ mymain(void)
     DO_TEST("q35",
             QEMU_CAPS_DEVICE, QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
-            QEMU_CAPS_ICH9_AHCI,
+            QEMU_CAPS_DRIVE, QEMU_CAPS_ICH9_AHCI,
             QEMU_CAPS_VGA, QEMU_CAPS_DEVICE_VIDEO_PRIMARY,
             QEMU_CAPS_VGA, QEMU_CAPS_VGA_QXL, QEMU_CAPS_DEVICE_QXL);
 
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml b/tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml
index 2a86e61..96f8eaf 100644
--- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml
@@ -14,6 +14,11 @@
   <on_crash>destroy</on_crash>
   <devices>
     <emulator>/usr/libexec/qemu-kvm</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='sda' bus='sata'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
     <controller type='pci' index='0' model='pcie-root'/>
     <controller type='pci' index='1' model='dmi-to-pci-bridge'/>
     <controller type='pci' index='2' model='pci-bridge'/>
-- 
1.7.11.7