On Thu, Mar 06, 2025 at 02:45:52PM +0100, BALATON Zoltan wrote: > On Thu, 6 Mar 2025, Daniel P. Berrangé wrote: > > On Thu, Mar 06, 2025 at 12:34:13PM +0100, Paolo Bonzini wrote: > > > Il gio 6 mar 2025, 10:27 Philippe Mathieu-Daudé <phi...@linaro.org> ha > > > scritto: > > > > > > > This API is to allow refactoring code for heterogeneous emulation, > > > > without changing user-facing behavior of current qemu-system binaries, > > > > which I now consider as 'legacy'. > > > > > > > > Once all current restrictions removed, the new qemu-system-heterogeneous > > > > binary is expected to run any combination of targets. > > > > > > > > qemu-system-$target will be a call to qemu-system-heterogeneous with > > > > a restricted subset, possibly in the form of: > > > > > > > > $ qemu-system-heterogeneous --target aarch64-softmmu > > > > > > > > > > Or just qemu-system I guess. > > > > > > ^ equivalent of today's qemu-system-aarch64 > > > > > > > > If you don't like 'qemu_legacy_binary_' prefix, I can use > > > > 'qemu_single_binary_' instead. > > > > > > > > > > Still there is a problem with renaming binaries (both the "qemu-kvm" case > > > and the good/bad case that Richard pointed out). > > > > We could special case the '-kvm' suffix, because by its nature it > > implies the current binary build target. > > > > > > > > I think you should try creating two versions of system/arch_init.c, so > > > that > > > it has a separate implementation for heterogeneous vs. single-target > > > binaries. Then you can keep separate linking steps for single-target > > > binaries and you naturally get the right target info from either the > > > target-specific arch_init-single.c, or the --target option for > > > arch_init-multi.c. > > > > > > (Is --target even necessary? As long as you have a way disambiguate > > > same-named machines like -M virt, and have no default machine in the > > > multi-target binary, you shouldn't need it). > > > > If we did 'query-machines' on qemu-system-heterogeneous, it would > > return all machines from all targets. To disambiguate naming there > > are various options > > > > * The query-machines command would have to gain a new 'target' > > field and we would have to document that uniqness is across > > the tuple (name, target), not merely name. That's a semantic > > change. > > > > We would still need a way to express the 'target' when asking > > to instantiate a machine > > > > * The query-machines command would have to gain a new 'target' > > paramter so callers can restrict the data they receive back > > > > We would still need a way to express the 'target' when asking > > to instantiate a machine > > > > * Rename all machine types so they are '<target>-<machine>' > > The query-machines command doesn't change. Apps would have > > to "parse" the machine name to see what 'target' each is > > associated with, or we include an explicit 'target' field > > in the returned data. Instianting a machine would not need > > changing > > I think -machine m68k:virt could work, -M help would list machines like: > > arm:raspi > i386:pc > etc. > > Management apps could easily find : to separate arch but those that don't > care about arch would just work and list more possible machines. Some > machines like pc or mac99 that may appear differently in different single > arch binary might need to get resolved first. Maybe need a way to search > machine list by pattern e.g. as -machine x86_64:help.
...except that custom structures/formats in command line args is something we've tried very hard to eliminate in Qemu, and instead model everything as a distinct fields, using QAPI, so... .. if you're meaning "arm:raspi" as a short hand for "target:machine" that would be a design anti-pattern, b ...if you're meaning that "arm:raspi" is the full machine name, to be strictly treated as an opaque string that would be acceptable. I rather think the latter would not end up being treated as an opaque string though - the tempetation to parse it & assign semantics to the pieces is just too great. So I'm not a fan of that approach. >From a QAPI design best pratice POV, the requirement would be for -machine target=arm,name=raspi With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
