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authorChristian Borntraeger <borntraeger@de.ibm.com>2020-05-05 09:27:15 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2020-05-05 11:15:05 +0200
commit5615e74f48dcc982655543e979b6c3f3f877e6f6 (patch)
treeabb0d9f0a74a5888e0b5fc5eb8c38f7ca393ede4 /arch/s390/kvm
parentMAINTAINERS: add a reviewer for KVM/s390 (diff)
downloadlinux-5615e74f48dcc982655543e979b6c3f3f877e6f6.tar.xz
linux-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.c4
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 */