On Tue, 5 May 2020 09:35:25 +0200 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > In LPAR we will only get an intercept for FC==3 for the PQAP > instruction. Running nested under z/VM can result in other intercepts as > well, for example PQAP(QCI). So the WARN_ON_ONCE is not right. Let > us simply remove it. While I agree with removing the WARN_ON_ONCE, I'm wondering why z/VM gives us intercepts for those fcs... is that just a result of nesting (or the z/VM implementation), or is there anything we might want to do? > > Cc: Pierre Morel <pmorel@xxxxxxxxxxxxx> > Cc: Tony Krowiak <akrowiak@xxxxxxxxxxxxx> > Reported-by: Qian Cai <cailca@xxxxxxxxxx> > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > --- > arch/s390/kvm/priv.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c > index 69a824f9ef0b..bbe46c6aedbf 100644 > --- a/arch/s390/kvm/priv.c > +++ b/arch/s390/kvm/priv.c > @@ -626,10 +626,12 @@ static int handle_pqap(struct kvm_vcpu *vcpu) > * available for the guest are AQIC and TAPQ with the t bit set > * since we do not set IC.3 (FIII) we currently will only intercept > * the AQIC function code. > + * Note: running nested under z/VM can result in intercepts, e.g. s/intercepts/intercepts for other function codes/ > + * for PQAP(QCI). We do not support this and bail out. > */ > reg0 = vcpu->run->s.regs.gprs[0]; > fc = (reg0 >> 24) & 0xff; > - if (WARN_ON_ONCE(fc != 0x03)) > + if (fc != 0x03) > return -EOPNOTSUPP; > > /* PQAP instruction is allowed for guest kernel only */
