From 857b8de96795646c5891cf44ae6fb19b9ff74bf9 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 3 Aug 2017 14:27:30 +0200 Subject: [PATCH] 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: # 4.8+ Reviewed-by: Janosch Frank Signed-off-by: Heiko Carstens Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger --- arch/s390/kvm/sthyi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) 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. -- 2.20.1