Re: [Libguestfs] [PATCH v2v v2 3/3] -o qemu: Always use -cpu host unless overridden by source hypervisor

As with the prior commit, prefer -cpu host for all guests (except when we have more information from the source hypervisor). Although there is the disadvantage that -cpu host is non-migratable, in practice it would be very difficult to live migrate a host launched using direct qemu commands. Note that after this change, gcaps_arch_min_version is basically an informational field. No output uses it, but it will appear in debug output and there's the possibility we might use it for a future output mode. Thanks: Laszlo Ersek --- lib/types.mli | 6 +++++- output/output_qemu.ml | 6 +----- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/lib/types.mli b/lib/types.mli index 743daa8a14..4a183dd3ae 100644 --- a/lib/types.mli +++ b/lib/types.mli @@ -268,7 +268,11 @@ type guestcaps = { minimum version. Notably RHEL >= 9 requires at least x86_64-v2. If the guest is capable of running on QEMU's default VCPU model - for the architecture ([-cpu qemu64]) then this is set to [0]. *) + for the architecture ([-cpu qemu64]) then this is set to [0]. + + Note this capability is not actually used by any current output + mode. It is retained in case we might use it in future, but we + might remove it if it is not used. *) gcaps_virtio_1_0 : bool; (** The guest supports the virtio devices that it does at the virtio-1.0 diff --git a/output/output_qemu.ml b/output/output_qemu.ml index 491906ebf9..2bbacb6eda 100644 --- a/output/output_qemu.ml +++ b/output/output_qemu.ml @@ -175,11 +175,7 @@ module QEMU = struct arg "-m" (Int64.to_string (source.s_memory /^ 1024L /^ 1024L)); - (match source.s_cpu_model, guestcaps.gcaps_arch_min_version with - | None, 0 -> () - | None, _ -> arg "-cpu" "host" - | Some model, _ -> arg "-cpu" model - ); + arg "-cpu" (Option.default "host" source.s_cpu_model);

if source.s_vcpu > 1 then ( (match source.s_cpu_topology with