Re: [GIT PULL] KVM/riscv changes for 6.17

[Paolo Bonzini <pbonzini@redhat.com>]

On 7/29/25 13:37, Radim Krčmář wrote:
> Sorry, I didn't try too hard to convince others after noticing it, and
> planned to fix the most significant breakage in later rcs.

You shouldn't have to convince anyone, 
Documentation/virt/kvm/review-checklist.rst is pretty clear: new state 
must include support for save/restore, new features must default to off, 
and the feature should be testable.

The file was just updated (and now makes further remarks about testing), 
but the same things were basically in the older version.

So you need:

- a KVM_ENABLE_CAP to enable/disable FWFT

- an ioctl to get the list of FWFT features (kind of like 
KVM_GET_MSR_INDEX_LIST on x86?  It seems unlikely that you get more than 
50 or 60)

- an ioctl to enable/disable FWFT individual features

- the GET/SET_ONE_REG to migrate the state etc.

- selftests


> (If FWFT wasn't enabled by default, sane userspace just wouldn't expose
>   FWFT to the guest until a proper KVM configuration was added).

That means that the bare minimum for inclusion in KVM is the first three 
bullets above.  But at this point, leaving out the fourth is just 
sloppy; and tests are not really optional unless you have already posted 
a userspace implementation.

Thanks,

Paolo