Re: [PATCH v9 02/24] KVM: Move architecture capability Kconfigs to header defines

[Steffen Eiden <seiden@linux.ibm.com>]

On Mon, Oct 12, 2026 at 07:53:43PM +0200, Paolo Bonzini wrote:
> On 9/30/26 19:34, Steffen Eiden wrote:
> > Historically, KVM feature opt-ins and callbacks were configured globally
> > via Kconfig symbols (CONFIG_HAVE_KVM_* and CONFIG_KVM_*).
> 
> Not all of them - there are many __KVM_HAVE_* symbols already.  In
> particular now there's both KVM_MSI and __KVM_HAVE_MSI/__KVM_HAVE_MSIX (but
> the latter is dead, so I have sent a patch to remove it).
> 
> There are several remaining CONFIG_HAVE_KVM_ARCH_* Kconfig symbols as well.
> That's okay, but it should be noted in the changelog that not all symbols
> were fixed.
> 
> Can you at least quickly provide a v2, that changes all symbols to
> __KVM_HAVE_<function-name> (and when not applicable __KVM_*, for example
> __KVM_HAVE_READONLY_MEM)?  I have already changed KVM_NO_MMIO to
> __KVM_NO_MMIO in kvm/queue.
>

Yes, no problem.

Using this pattern would reintroduce __KVM_HAVE_MSI then, right?
I would create those symbols:

  - __KVM_HAVE_INVALID_WAKEUPS 		(formerly KVM_INVALID_WAKEUPS)
  - __KVM_HAVE_MSI			(formerly HAVE_KVM_MSI)
  - __KVM_HAVE_NO_POLL			(formerly HAVE_KVM_NO_POLL)
  - __KVM_HAVE_READONLY_MEM		(formerly HAVE_KVM_READONLY_MEM)
  - __KVM_HAVE_VCPU_RUN_PID_CHANGE	(formerly HAVE_KVM_VCPU_RUN_PID_CHANGE)

OK?

	Steffen
> Thanks,
> 
> Paolo
> 
> > Replace these global Kconfig options with architecture-specific opt-in
> > defines in <asm/kvm_host.h> and standardize their naming by dropping the
> > HAVE_ prefix:
> >    - KVM_INVALID_WAKEUPS
> >    - KVM_MSI			(formerly HAVE_KVM_MSI)
> >    - KVM_NO_POLL			(formerly HAVE_KVM_NO_POLL)
> >    - KVM_READONLY_MEM		(formerly HAVE_KVM_READONLY_MEM)
> >    - KVM_VCPU_RUN_PID_CHANGE	(formerly HAVE_KVM_VCPU_RUN_PID_CHANGE)
> > 
> > This allows each architecture and guest implementation to configure its
> > supported capabilities independently in its kvm_host header and eliminates
> > unnecessary fallback stubs across different KVM targets.
> > 
> > Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>