On Tue, 5 May 2020 09:55:36 +0200 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > On 05.05.20 09:53, Cornelia Huck wrote: > > 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? > > Yes nesting. > The ECA bit for interpretion is an effective one. So if the ECA bit is off > in z/VM (no crypto cards) our ECA bit is basically ignored as these bits > are ANDed. Ok, that makes sense, even if it is rather ugly. With the comment tweaked, Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> > I asked Tony to ask the z/VM team if that is the case here. > > > > >> > >> 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 */ > > >
