Re: [PATCH 2/2] KVM: s390: selftests: Add load psw bear test

[Janosch Frank <frankja@linux.ibm.com>]

On 3/25/26 11:29, Christian Borntraeger wrote:
> Had a 2nd look.
> Just wanted to test that lpswe does indeed leaves the BEAR unchanged and then I
> realized that lpswey does not work in our guest due to missing cpu model.
> So either remove the lpswey test for now or fix it.
> Something like this on top

Yeah one additional problem is that a PGM during guest execution might 
easily be missed since there are no checks and guest execution currently 
actually ends with an operation exception as well.

I'll remove the lpswey test for this series and will try to come up with 
a fix for the PGM issue for 7.1 or 7.2.


> 
> --- a/tools/testing/selftests/kvm/s390/bear.c
> +++ b/tools/testing/selftests/kvm/s390/bear.c
> @@ -22,7 +22,10 @@ static void guest_lpswey(void)
>           u64 bear;
>    
>           asm volatile (
> -               "       larl    %%r3,lpswey_addr\n"
> +               "       larl    %%r3,jump_addr\n"
> +               "jump_addr:\n"
> +               "       j lpswey_addr\n"
> +               "       nop\n"
>                   "lpswey_addr:\n"
>                   "       .insn   siy,0xeb0000000071,%[psw],0\n"
>                   "       nop\n"
> @@ -107,21 +110,30 @@ static void test_lpswey(void)
>           struct kvm_vcpu *vcpu;
>           struct kvm_run *run;
>           struct kvm_vm *vm;
> +       struct kvm_s390_vm_cpu_processor proc;
> +       int r;
> +
> +       vm = vm_create(1);
> +       __kvm_device_attr_get(vm->fd, KVM_S390_VM_CPU_MODEL,
> +                                 KVM_S390_VM_CPU_PROCESSOR, &proc);
> +       proc.fac_list[3] |= 0x4000000000000000UL;
> +       r = __kvm_device_attr_set(vm->fd, KVM_S390_VM_CPU_MODEL,
> +                                 KVM_S390_VM_CPU_PROCESSOR, &proc);
> +       vcpu = vm_vcpu_add(vm, 0, guest_lpswey);
>    
> -       vm = vm_create_with_one_vcpu(&vcpu, guest_lpswey);
>           inject_mcheck(vcpu);
>           run = vcpu->run;
>           vcpu_run(vcpu);
> -       ksft_test_result(run->s.regs.gprs[3] != run->s.regs.gprs[4],
> -                        "emulation: lpswey bear does not match\n");
> +       ksft_test_result(run->s.regs.gprs[3] == run->s.regs.gprs[4],
> +                        "emulation: lpswey bear does match previous\n");
>           kvm_vm_free(vm);
>    
>           vm = vm_create_with_one_vcpu(&vcpu, guest_lpswey);
>           run = vcpu->run;
>           vcpu_run(vcpu);
>           ksft_test_result(run->s.regs.gprs[3] &&
> -                        run->s.regs.gprs[3] != run->s.regs.gprs[4],
> -                        "interpretation: lpswey bear does not match\n");
> +                        run->s.regs.gprs[3] == run->s.regs.gprs[4],
> +                        "interpretation: lpswey bear does match previous\n");
>           kvm_vm_free(vm);
>    }
>    
>