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| author |   Christian Borntraeger <borntraeger@de.ibm.com> | 2020-05-05 09:27:15 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2020-05-05 11:15:05 +0200 |
| commit | 5615e74f48dcc982655543e979b6c3f3f877e6f6 (patch) | |
| tree | abb0d9f0a74a5888e0b5fc5eb8c38f7ca393ede4 /arch/s390/kvm | |
| parent | MAINTAINERS: add a reviewer for KVM/s390 (diff) | |
| download | linux-dev-5615e74f48dcc982655543e979b6c3f3f877e6f6.tar.xz linux-dev-5615e74f48dcc982655543e979b6c3f3f877e6f6.zip | |
KVM: s390: Remove false WARN_ON_ONCE for the PQAP instruction
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 as ECA_APIE is an effective bit: If one hypervisor layer has
turned this bit off, the end result will be that we will get intercepts for
all function codes. Usually the first one will be a query like PQAP(QCI).
So the WARN_ON_ONCE is not right. Let us simply remove it.
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: stable@vger.kernel.org # v5.3+
Fixes: e5282de93105 ("s390: ap: kvm: add PQAP interception for AQIC")
Link: https://lore.kernel.org/kvm/20200505083515.2720-1-borntraeger@de.ibm.com
Reported-by: Qian Cai <cailca@icloud.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm')
| -rw-r--r-- | arch/s390/kvm/priv.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 69a824f9ef0b..893893642415 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 for other + * function codes, e.g. 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 */ |