qemu: caps: Add capability for 'write-cache' parameter of disk frontends

QEMU translates the cache mode of a disk internally into 3 flags.
'write-cache' is a flag of the frontend while others are flag of the
backing storage. Add capability which will allow expressing it via the
frontend attribute.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>

tests/qemucapabilitiesdata/caps_2.10.0.aarch64.xml

@@ -152,6 +152,7 @@
   <flag name='pl011'/>
   <flag name='dump-completed'/>
   <flag name='qcow2-luks'/>
+  <flag name='disk-write-cache'/>
   <version>2010000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>303541</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.10.0.ppc64.xml

@@ -151,6 +151,7 @@
   <flag name='machine.pseries.max-cpu-compat'/>
   <flag name='dump-completed'/>
   <flag name='qcow2-luks'/>
+  <flag name='disk-write-cache'/>
   <version>2010000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>382824</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.10.0.s390x.xml

@@ -112,6 +112,7 @@
   <flag name='iscsi.password-secret'/>
   <flag name='dump-completed'/>
   <flag name='qcow2-luks'/>
+  <flag name='disk-write-cache'/>
   <version>2010000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>303326</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.10.0.x86_64.xml

@@ -195,6 +195,7 @@
   <flag name='isa-serial'/>
   <flag name='dump-completed'/>
   <flag name='qcow2-luks'/>
+  <flag name='disk-write-cache'/>
   <version>2010000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>344938</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.11.0.s390x.xml

@@ -117,6 +117,7 @@
   <flag name='virtio-tablet-ccw'/>
   <flag name='qcow2-luks'/>
   <flag name='seccomp-blacklist'/>
+  <flag name='disk-write-cache'/>
   <version>2011000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>342058</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.12.0.aarch64.xml

@@ -156,6 +156,7 @@
   <flag name='pcie-pci-bridge'/>
   <flag name='seccomp-blacklist'/>
   <flag name='query-cpus-fast'/>
+  <flag name='disk-write-cache'/>
   <version>2011090</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>342346</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.12.0.ppc64.xml

@@ -153,6 +153,7 @@
   <flag name='qcow2-luks'/>
   <flag name='seccomp-blacklist'/>
   <flag name='query-cpus-fast'/>
+  <flag name='disk-write-cache'/>
   <version>2011090</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>419215</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.12.0.s390x.xml

@@ -118,6 +118,7 @@
   <flag name='qcow2-luks'/>
   <flag name='seccomp-blacklist'/>
   <flag name='query-cpus-fast'/>
+  <flag name='disk-write-cache'/>
   <version>2011090</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>0</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.12.0.x86_64.xml

@@ -194,6 +194,7 @@
   <flag name='pcie-pci-bridge'/>
   <flag name='seccomp-blacklist'/>
   <flag name='query-cpus-fast'/>
+  <flag name='disk-write-cache'/>
   <version>2011090</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>390060</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.7.0.s390x.xml

@@ -102,6 +102,7 @@
   <flag name='virtio-blk.num-queues'/>
   <flag name='sclplmconsole'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2007000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>216732</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.7.0.x86_64.xml

@@ -175,6 +175,7 @@
   <flag name='virtio-blk.num-queues'/>
   <flag name='isa-serial'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2007000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>239029</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.8.0.s390x.xml

@@ -104,6 +104,7 @@
   <flag name='virtio-blk.num-queues'/>
   <flag name='sclplmconsole'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2007093</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>241633</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.8.0.x86_64.xml

@@ -177,6 +177,7 @@
   <flag name='virtio-blk.num-queues'/>
   <flag name='isa-serial'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2008000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>255684</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.9.0.ppc64.xml

@@ -143,6 +143,7 @@
   <flag name='iscsi.password-secret'/>
   <flag name='isa-serial'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2009000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>346538</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.9.0.s390x.xml

@@ -107,6 +107,7 @@
   <flag name='disk-share-rw'/>
   <flag name='iscsi.password-secret'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2009000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>265051</microcodeVersion>

tests/qemucapabilitiesdata/caps_2.9.0.x86_64.xml

@@ -190,6 +190,7 @@
   <flag name='iscsi.password-secret'/>
   <flag name='isa-serial'/>
   <flag name='dump-completed'/>
+  <flag name='disk-write-cache'/>
   <version>2009000</version>
   <kvmVersion>0</kvmVersion>
   <microcodeVersion>320947</microcodeVersion>