Re: [PATCH v4 24/27] KVM: s390: arm64: Implement vm/vcpu create destroy.

[Steffen Eiden]

On Tue, Jul 07, 2026 at 04:10:19PM +0100, Marc Zyngier wrote:
> On Mon, 06 Jul 2026 09:52:24 +0100,
> Steffen Eiden <seiden@xxxxxxxxxxxxx> wrote:
> > 
> > Implement init and destroy IOCTLS for vcpu and vm.
> > Implement arch vm IOCTL. Use s390 gmap.
> > 
> > Co-developed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> > Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> > Co-developed-by: Andreas Grapentin <gra@xxxxxxxxxxxxx>
> > Signed-off-by: Andreas Grapentin <gra@xxxxxxxxxxxxx>
> > Co-developed-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
> > Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
> > Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
> > ---
> >  arch/s390/kvm/arm64/arm.c       | 190 ++++++++++++++++++++++++++++++++
> >  arch/s390/kvm/arm64/arm.h       |  56 ++++++++++
> >  arch/s390/kvm/gmap/faultin.c    |   5 +
> >  arch/s390/kvm/gmap/gmap.c       |   4 +
> >  arch/s390/kvm/gmap/trace-gmap.h |  13 +++
> >  5 files changed, 268 insertions(+)
> > 
> > diff --git a/arch/s390/kvm/arm64/arm.c b/arch/s390/kvm/arm64/arm.c
> > index 19249ec5c539..3a4092698fae 100644
> > --- a/arch/s390/kvm/arm64/arm.c
> > +++ b/arch/s390/kvm/arm64/arm.c
> > @@ -8,6 +8,10 @@
> >  #include <linux/kvm_types.h>
> >  #include <linux/kvm_host.h>
> >  
> > +#include <arm64/kvm_mmu.h>
> > +
> > +#include <gmap.h>
> > +
> >  #include "arm.h"
> >  
> >  static unsigned long system_supported_vcpu_features(void);
> > @@ -31,6 +35,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> >  		break;
> >  	case KVM_CAP_IOEVENTFD:
> >  	case KVM_CAP_ARM_USER_IRQ:
> > +	case KVM_CAP_PRE_FAULT_MEMORY:
> 
> arm64 *doesn't* support this yet. Please make sure you don't deviate
> from what arm64 currently supports.
>

I hoped the corresponding arm64 series is merged when we got this :) 

I will remove this advertisement. I'll keep the implementation as the compiler
expect that function to be present anyways, as native s390 KVM now implements
this CAP. OK? 


> Thanks,
> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.