On 6/17/21 1:09 PM, Markus Armbruster wrote: > Valeriy Vdovin <valeriy.vdovin@xxxxxxxxxxxxx> writes: > >> On Thu, Jun 17, 2021 at 07:22:36AM +0200, Markus Armbruster wrote: >>> Valeriy Vdovin <valeriy.vdovin@xxxxxxxxxxxxx> writes: >>> >>>> Introducing new qapi method 'query-kvm-cpuid'. This method can be used to >>> >>> It's actually a QMP command. There are no "qapi methods". >>> >>>> get virtualized cpu model info generated by QEMU during VM initialization in >>>> the form of cpuid representation. >>>> >>>> Diving into more details about virtual cpu generation: QEMU first parses '-cpu' >>> >>> virtual CPU >>> >>>> command line option. From there it takes the name of the model as the basis for >>>> feature set of the new virtual cpu. After that it uses trailing '-cpu' options, >>>> that state if additional cpu features should be present on the virtual cpu or >>>> excluded from it (tokens '+'/'-' or '=on'/'=off'). >>>> After that QEMU checks if the host's cpu can actually support the derived >>>> feature set and applies host limitations to it. >>>> After this initialization procedure, virtual cpu has it's model and >>>> vendor names, and a working feature set and is ready for identification >>>> instructions such as CPUID. >>>> >>>> Currently full output for this method is only supported for x86 cpus. >>> >>> Not sure about "currently": the interface looks quite x86-specific to me. >>> >> Yes, at some point I was thinking this interface could become generic, >> but does not seem possible, so I'll remove this note. >> >>> The commit message doesn't mention KVM except in the command name. The >>> schema provides the command only if defined(CONFIG_KVM). >>> >>> Can you explain why you need the restriction to CONFIG_KVM? >>> >> This CONFIG_KVM is used as a solution to a broken build if --disable-kvm >> flag is set. I was choosing between this and writing empty implementation into >> kvm-stub.c > > If the command only makes sense for KVM, then it's named correctly, but > the commit message lacks a (brief!) explanation why it only makes for > KVM. Is it meaningful for HVF? > > If it just isn't implemented for anything but KVM, then putting "kvm" > into the command name is a bad idea. Also, the commit message should > briefly note the restriction to KVM. > > Pick one :) > > [...] > >
