Add unsafe cache mode support for disk driver

QEMU 0.13 introduced cache=unsafe for -drive, this patch exposes
it in the libvirt layer.

  * Introduced a new QEMU capability flag ($prefix_CACHE_UNSAFE),
    as even if $prefix_CACHE_V2 is set, we can't know if unsafe
    is supported.

  * Improved the reliability of qemu cache type detection.

5 files changed, 45 insertions, 0 deletions

diff --git a/tests/qemuargv2xmltest.c b/tests/qemuargv2xmltest.c
index 91f15af6b..6a7963086 100644
--- a/tests/qemuargv2xmltest.c
+++ b/tests/qemuargv2xmltest.c
@@ -169,6 +169,7 @@ mymain(void)
     DO_TEST("disk-drive-cache-v2-wb");
     DO_TEST("disk-drive-cache-v2-none");
     DO_TEST("disk-drive-cache-directsync");
+    DO_TEST("disk-drive-cache-unsafe");
     DO_TEST("disk-drive-network-nbd");
     DO_TEST("disk-drive-network-rbd");
     DO_TEST("disk-drive-network-sheepdog");
diff --git a/tests/qemuhelptest.c b/tests/qemuhelptest.c
index 933d55630..0ff823658 100644
--- a/tests/qemuhelptest.c
+++ b/tests/qemuhelptest.c
@@ -165,6 +165,7 @@ mymain(void)
             QEMU_CAPS_MIGRATE_QEMU_TCP,
             QEMU_CAPS_MIGRATE_QEMU_EXEC,
             QEMU_CAPS_DRIVE_CACHE_V2,
+            QEMU_CAPS_DRIVE_CACHE_UNSAFE,
             QEMU_CAPS_KVM,
             QEMU_CAPS_DRIVE_FORMAT,
             QEMU_CAPS_DRIVE_SERIAL,
@@ -408,6 +409,7 @@ mymain(void)
             QEMU_CAPS_MIGRATE_QEMU_TCP,
             QEMU_CAPS_MIGRATE_QEMU_EXEC,
             QEMU_CAPS_DRIVE_CACHE_V2,
+            QEMU_CAPS_DRIVE_CACHE_UNSAFE,
             QEMU_CAPS_KVM,
             QEMU_CAPS_DRIVE_FORMAT,
             QEMU_CAPS_DRIVE_SERIAL,
@@ -460,6 +462,7 @@ mymain(void)
             QEMU_CAPS_MIGRATE_QEMU_TCP,
             QEMU_CAPS_MIGRATE_QEMU_EXEC,
             QEMU_CAPS_DRIVE_CACHE_V2,
+            QEMU_CAPS_DRIVE_CACHE_UNSAFE,
             QEMU_CAPS_KVM,
             QEMU_CAPS_DRIVE_FORMAT,
             QEMU_CAPS_DRIVE_SERIAL,
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args
new file mode 100644
index 000000000..f8ddcd849
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args
@@ -0,0 +1,5 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \
+pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=ide,bus=0,unit=0,\
+format=qcow2,cache=unsafe -drive file=/dev/HostVG/QEMUGuest2,if=ide,\
+media=cdrom,bus=1,unit=0,format=raw -net none -serial none -parallel none -usb
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml
new file mode 100644
index 000000000..37185f64d
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml
@@ -0,0 +1,33 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219136</memory>
+  <currentMemory>219136</currentMemory>
+  <vcpu>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </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='block' device='disk'>
+      <driver name='qemu' type='qcow2' cache='unsafe'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' unit='0'/>
+    </disk>
+    <disk type='block' device='cdrom'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest2'/>
+      <target dev='hdc' bus='ide'/>
+      <readonly/>
+      <address type='drive' controller='0' bus='1' unit='0'/>
+    </disk>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 1dc6a0175..9e174b378 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -341,6 +341,9 @@ mymain(void)
     DO_TEST("disk-drive-cache-directsync", false,
             QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2,
             QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC, QEMU_CAPS_DRIVE_FORMAT);
+    DO_TEST("disk-drive-cache-unsafe", false,
+            QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2,
+            QEMU_CAPS_DRIVE_CACHE_UNSAFE, QEMU_CAPS_DRIVE_FORMAT);
     DO_TEST("disk-drive-network-nbd", false,
             QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT);
     DO_TEST("disk-drive-network-rbd", false,