4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Heiko Carstens <[email protected]> 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 <[email protected]> Signed-off-by: Heiko Carstens <[email protected]> Reviewed-by: David Hildenbrand <[email protected]> Reviewed-by: Cornelia Huck <[email protected]> Signed-off-by: Christian Borntraeger <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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.
