On 9/8/20 1:21 PM, Ján Tomko wrote:
On a Tuesday in 2020, Michal Privoznik wrote:
This capability corresponds to '-machine memory-backend=' command line argument. Unfortunately, it is not possible for us to detect the capability via QMP and therefore we have to have a version check.
The QEMU capability was introduced in v5.1.0-3-gc556600598.
Please rephrase this or drop the period at the end, e.g.:
QEMU commit v5.1.0-3-gc556600598 introduced the capability.
(to make it easier to select)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_capabilities.c | 7 +++++++ src/qemu/qemu_capabilities.h | 3 +++ tests/qemucapabilitiesdata/caps_5.2.0.x86_64.xml | 1 + 3 files changed, 11 insertions(+)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index dcfd7cdd4e..d0a7c7b30e 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -597,6 +597,9 @@ VIR_ENUM_IMPL(virQEMUCaps, "spapr-tpm-proxy", "numa.hmat", "blockdev-hostdev-scsi", + + /* 380 */ + "machine.memory-backend", );
@@ -5104,6 +5107,10 @@ virQEMUCapsInitQMPVersionCaps(virQEMUCapsPtr qemuCaps) /* TCG couldn't be disabled nor queried until QEMU 2.10 */ if (qemuCaps->version < 2010000) virQEMUCapsSet(qemuCaps, QEMU_CAPS_TCG); + + /* no way to query for -machine memory-backend */ + if (qemuCaps->version >= 5001050)
That's a git version.
Also, the above mentioned commit introduces the 'default-ram-id' property, which does show up in our capability replies file.
Can't we safely assume that its presence also means that -machine memory-backend is supported?
Good point. We can do that. However, I will need to do a slight change to 6/7 to qemuTestCapsCacheInsert() because there I'm filling default-ram-id for all qemuCaps, even old versions that don't have it in real world. So basically, I will need to move this version check into qemuTestCapsCacheInsert() but I guess that's okay if I put a comment next to it. Michal