Commit 857b8de9 authored by Heiko Carstens's avatar Heiko Carstens Committed by Christian Borntraeger

KVM: s390: sthyi: fix specification exception detection

sthyi should only generate a specification exception if the function
code is zero and the response buffer is not on a 4k boundary.

The current code would also test for unknown function codes if the
response buffer, that is currently only defined for function code 0,
is not on a 4k boundary and incorrectly inject a specification
exception instead of returning with condition code 3 and return code 4
(unsupported function code).

Fix this by moving the boundary check.

Fixes: 95ca2cb5 ("KVM: s390: Add sthyi emulation")
Cc: <stable@vger.kernel.org> # 4.8+
Reviewed-by: default avatarJanosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 4a4eefcd
......@@ -425,7 +425,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
VCPU_EVENT(vcpu, 3, "STHYI: fc: %llu addr: 0x%016llx", code, addr);
trace_kvm_s390_handle_sthyi(vcpu, code, addr);
if (reg1 == reg2 || reg1 & 1 || reg2 & 1 || addr & ~PAGE_MASK)
if (reg1 == reg2 || reg1 & 1 || reg2 & 1)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
if (code & 0xffff) {
......@@ -433,6 +433,9 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
goto out;
}
if (addr & ~PAGE_MASK)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
/*
* If the page has not yet been faulted in, we want to do that
* now and not after all the expensive calculations.
......
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