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Diffstat (limited to 'arch/s390/kvm/intercept.c')
-rw-r--r--arch/s390/kvm/intercept.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 7a27eebab28a..59920f96ebc0 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -238,7 +238,9 @@ static int handle_prog(struct kvm_vcpu *vcpu)
vcpu->stat.exit_program_interruption++;
if (guestdbg_enabled(vcpu) && per_event(vcpu)) {
- kvm_s390_handle_per_event(vcpu);
+ rc = kvm_s390_handle_per_event(vcpu);
+ if (rc)
+ return rc;
/* the interrupt might have been filtered out completely */
if (vcpu->arch.sie_block->iprcc == 0)
return 0;
@@ -359,6 +361,9 @@ static int handle_partial_execution(struct kvm_vcpu *vcpu)
static int handle_operexc(struct kvm_vcpu *vcpu)
{
+ psw_t oldpsw, newpsw;
+ int rc;
+
vcpu->stat.exit_operation_exception++;
trace_kvm_s390_handle_operexc(vcpu, vcpu->arch.sie_block->ipa,
vcpu->arch.sie_block->ipb);
@@ -369,6 +374,24 @@ static int handle_operexc(struct kvm_vcpu *vcpu)
if (vcpu->arch.sie_block->ipa == 0 && vcpu->kvm->arch.user_instr0)
return -EOPNOTSUPP;
+ rc = read_guest_lc(vcpu, __LC_PGM_NEW_PSW, &newpsw, sizeof(psw_t));
+ if (rc)
+ return rc;
+ /*
+ * Avoid endless loops of operation exceptions, if the pgm new
+ * PSW will cause a new operation exception.
+ * The heuristic checks if the pgm new psw is within 6 bytes before
+ * the faulting psw address (with same DAT, AS settings) and the
+ * new psw is not a wait psw and the fault was not triggered by
+ * problem state.
+ */
+ oldpsw = vcpu->arch.sie_block->gpsw;
+ if (oldpsw.addr - newpsw.addr <= 6 &&
+ !(newpsw.mask & PSW_MASK_WAIT) &&
+ !(oldpsw.mask & PSW_MASK_PSTATE) &&
+ (newpsw.mask & PSW_MASK_ASC) == (oldpsw.mask & PSW_MASK_ASC) &&
+ (newpsw.mask & PSW_MASK_DAT) == (oldpsw.mask & PSW_MASK_DAT))
+ return -EOPNOTSUPP;
return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
}

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