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authorHeiko Carstens <heiko.carstens@de.ibm.com>2017-08-03 14:27:30 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2017-08-21 15:34:54 +0200
commit857b8de96795646c5891cf44ae6fb19b9ff74bf9 (patch)
tree3afa2096610f6a5f76f8234c0e10ee3233003c71 /arch/s390
parent4a4eefcd0e49f9f339933324c1bde431186a0a7d (diff)
downloadlinux-857b8de96795646c5891cf44ae6fb19b9ff74bf9.tar.gz
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: 95ca2cb57985 ("KVM: s390: Add sthyi emulation")
Cc: <stable@vger.kernel.org> # 4.8+
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@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')
-rw-r--r--arch/s390/kvm/sthyi.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/s390/kvm/sthyi.c b/arch/s390/kvm/sthyi.c
index 2773a2f6a5c4..a2e5c24f47a7 100644
--- a/arch/s390/kvm/sthyi.c
+++ b/arch/s390/kvm/sthyi.c
@@ -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.