Re: [PATCH 06/12] KVM: s390: exploit GISA and AIV for emulated interrupts

[Heiko Carstens <heiko.carstens@de.ibm.com>]

On Tue, Jan 16, 2018 at 09:02:11PM +0100, Christian Borntraeger wrote:
> +static int __do_deliver_io(struct kvm_vcpu *vcpu, struct kvm_s390_io_info *io)
> +{
> +	int rc;
> +
> +	rc  = put_guest_lc(vcpu, io->subchannel_id,
> +			   (u16 *)__LC_SUBCHANNEL_ID);
> +	rc |= put_guest_lc(vcpu, io->subchannel_nr,
> +			   (u16 *)__LC_SUBCHANNEL_NR);
> +	rc |= put_guest_lc(vcpu, io->io_int_parm,
> +			   (u32 *)__LC_IO_INT_PARM);
> +	rc |= put_guest_lc(vcpu, io->io_int_word,
> +			   (u32 *)__LC_IO_INT_WORD);

They all fit into one line now ;)

> +	rc |= write_guest_lc(vcpu, __LC_IO_OLD_PSW,
> +			     &vcpu->arch.sie_block->gpsw,
> +			     sizeof(psw_t));
> +	rc |= read_guest_lc(vcpu, __LC_IO_NEW_PSW,
> +			    &vcpu->arch.sie_block->gpsw,
> +			    sizeof(psw_t));
> +	return rc;
> +}

return rc = -EFAULT : 0;

from below should be moved to this function, so it has a well defined
return value instead of random garbage. Well, it's -EFAULT or 0 currently
anyway, but nobody knows...

>  static int __must_check __deliver_io(struct kvm_vcpu *vcpu,
>  				     unsigned long irq_type)
>  {
...
> +out:
>  	return rc ? -EFAULT : 0;
>  }