Re: [libvirt] [PATCH 4/6] qemu: caps: Add capability for 'write-cache' parameter of disk frontends
On 04/04/2018 04:13 AM, Peter Krempa wrote:
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(a)redhat.com>
---
src/qemu/qemu_capabilities.c | 5 +++++
src/qemu/qemu_capabilities.h | 1 +
tests/qemucapabilitiesdata/caps_2.10.0.aarch64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.10.0.ppc64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.10.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.10.0.x86_64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.11.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.12.0.aarch64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.12.0.ppc64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.12.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.12.0.x86_64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.7.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.7.0.x86_64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.8.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.8.0.x86_64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.9.0.ppc64.xml | 1 +
tests/qemucapabilitiesdata/caps_2.9.0.s390x.xml | 1 +
tests/qemucapabilitiesdata/caps_2.9.0.x86_64.xml | 1 +
18 files changed, 22 insertions(+)
Will require merges with top of tree, but that's a trivial exercise.
Curious though - the testing patch 6 of this series would seem to imply
that this feature is only available for at least QEMU 2.12 on x64_64;
however, the bit shows up starting in 2.7 on other arches, so since
patch 5 only uses QEMU_CAPS_DISK_WRITE_CACHE to decide whether to use
this or not, doesn't that imply earlier versions could use this? or
that the testing should be different?
John