Re: [PATCH v2 2/2] target/s390x/kvm: Simplify the GPRs, ACRs, CRs and prefix synchronization code

[Christian Borntraeger <borntraeger@linux.ibm.com>]

Am 09.10.23 um 19:07 schrieb Thomas Huth:
[...]

> @@ -483,20 +482,14 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>       cs->kvm_run->psw_addr = env->psw.addr;
>       cs->kvm_run->psw_mask = env->psw.mask;
>   
> -    if (can_sync_regs(cs, KVM_SYNC_GPRS)) {
> -        for (i = 0; i < 16; i++) {
> -            cs->kvm_run->s.regs.gprs[i] = env->regs[i];
> -            cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_GPRS;
> -        }
> -    } else {
> -        for (i = 0; i < 16; i++) {
> -            regs.gprs[i] = env->regs[i];
> -        }
> -        r = kvm_vcpu_ioctl(cs, KVM_SET_REGS, &regs);
> -        if (r < 0) {
> -            return r;
> -        }
> -    }
> +    g_assert((cs->kvm_run->kvm_valid_regs & KVM_SYNC_REQUIRED_BITS) ==
> +             KVM_SYNC_REQUIRED_BITS);
> +    cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_REQUIRED_BITS;
> +    memcpy(cs->kvm_run->s.regs.gprs, env->regs, sizeof(cs->kvm_run->s.regs.gprs));


> +    memcpy(cs->kvm_run->s.regs.acrs, env->aregs, sizeof(cs->kvm_run->s.regs.acrs));
> +    memcpy(cs->kvm_run->s.regs.crs, env->cregs, sizeof(cs->kvm_run->s.regs.crs));
> +
> +    cs->kvm_run->s.regs.prefix = env->psa;

These 3 have only been saved for level> KVM_PUT_RUNTIME_STATE. By moving the memcpy
into this position you would always write them. Probably ok but a change in
behaviour. Was this intentional?