| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 31/84] KVM: s390: sthyi: fix specification exception detection | Date | Mon, 28 Aug 2017 10:04:56 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens <heiko.carstens@de.ibm.com>
commit 857b8de96795646c5891cf44ae6fb19b9ff74bf9 upstream.
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") 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/s390/kvm/sthyi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/s390/kvm/sthyi.c +++ b/arch/s390/kvm/sthyi.c @@ -422,7 +422,7 @@ 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) { @@ -430,6 +430,9 @@ 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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