On 13/11/2025 20.32, Peter Xu wrote:
On Thu, Nov 13, 2025 at 12:46:55PM -0500, Michael S. Tsirkin wrote:
failing to start a perfectly good qemu which used to work
because you changed kernels is better than failing to migrate how?
I agree this is not pretty.
The very original proposal was having extra features to be OFF by default,
only allow explicit selections to enable them when the mgmt / user is aware
of the possible hosts to run on top.
Could it maybe be tied to the "-nodefaults" option of QEMU? If you run QEMU
with "-nodefaults" (which you should do when planning a migration later),
these extra features that depend on the kernel version stay OFF. If you run
QEMU without "-nodefaults", QEMU could enable them if supported by the
kernel. So that would benefit both, the people running QEMU via management
layers (using -nodefaults), and the people who just want to quickly launch
QEMU on the command line. WDYT?
Thomas
