Re: [PATCH v8 1/4] KVM: s390: Add new reset vcpu API

[Christian Borntraeger <borntraeger@xxxxxxxxxx>]

On 29.01.20 21:03, Janosch Frank wrote:
[...]> +static void kvm_arch_vcpu_ioctl_initial_reset(struct kvm_vcpu *vcpu)
> +{
> +	/* Initial reset is a superset of the normal reset */
> +	kvm_arch_vcpu_ioctl_normal_reset(vcpu);
> +
> +	/* this equals initial cpu reset in pop, but we don't switch to ESA */
> +	vcpu->arch.sie_block->gpsw.mask = 0;
> +	vcpu->arch.sie_block->gpsw.addr = 0;
> +	kvm_s390_set_prefix(vcpu, 0);
> +	kvm_s390_set_cpu_timer(vcpu, 0);
> +	vcpu->arch.sie_block->ckc = 0;
> +	vcpu->arch.sie_block->todpr = 0;
> +	memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gcr));
> +	vcpu->arch.sie_block->gcr[0] = CR0_INITIAL_MASK;
> +	vcpu->arch.sie_block->gcr[14] = CR14_INITIAL_MASK;
> +	/* make sure the new fpc will be lazily loaded */
> +	save_fpu_regs();

see my other patch. We should rebase this series and fix it here as well

> +	current->thread.fpu.fpc = 0;
> +	vcpu->arch.sie_block->gbea = 1;
> +	vcpu->arch.sie_block->pp = 0;
> +	vcpu->arch.sie_block->fpf &= ~FPF_BPBC;
> +}
> +
> +static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_sync_regs *regs = &vcpu->run->s.regs;
> +
> +	/* Clear reset is a superset of the initial reset */
> +	kvm_arch_vcpu_ioctl_initial_reset(vcpu);
> +
> +	memset(&regs->gprs, 0, sizeof(regs->gprs));
> +	memset(&regs->vrs, 0, sizeof(regs->vrs));
> +	memset(&regs->acrs, 0, sizeof(regs->acrs));
> +
> +	regs->etoken = 0;
> +	regs->etoken_extension = 0;
> +
> +	memset(&regs->gscb, 0, sizeof(regs->gscb));


> +	if (MACHINE_HAS_GS) {
> +		preempt_disable();
> +		__ctl_set_bit(2, 4);
> +		if (current->thread.gs_cb) {
> +			vcpu->arch.host_gscb = current->thread.gs_cb;
> +			save_gs_cb(vcpu->arch.host_gscb);
> +		}
> +		if (vcpu->arch.gs_enabled) {
> +			current->thread.gs_cb = (struct gs_cb *)
> +				&vcpu->run->s.regs.gscb;
> +			restore_gs_cb(current->thread.gs_cb);
> +		}
> +		preempt_enable();
> +	}

I think this hunk can go? (same reason as for floating point)


Other than that this looks good.