From 684135e0962fce7946a89f50cf6c7ffa78a11b09 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 17 Apr 2014 09:57:10 +0200 Subject: [PATCH] KVM: s390: Avoid endless loops of specification exceptions If the new PSW for program interrupts is invalid, the VM ends up in an endless loop of specification exceptions. Since there is not much left we can do in this case, we should better drop to userspace instead so that the crash can be reported to the user. Signed-off-by: Thomas Huth Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger --- arch/s390/kvm/intercept.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index bd607cf01a5d..ddc69f5f5e19 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -195,6 +195,7 @@ static int handle_itdb(struct kvm_vcpu *vcpu) static int handle_prog(struct kvm_vcpu *vcpu) { struct kvm_s390_pgm_info pgm_info; + psw_t psw; int rc; vcpu->stat.exit_program_interruption++; @@ -207,7 +208,14 @@ static int handle_prog(struct kvm_vcpu *vcpu) } trace_kvm_s390_intercept_prog(vcpu, vcpu->arch.sie_block->iprcc); - + if (vcpu->arch.sie_block->iprcc == PGM_SPECIFICATION) { + rc = read_guest_lc(vcpu, __LC_PGM_NEW_PSW, &psw, sizeof(psw_t)); + if (rc) + return rc; + /* Avoid endless loops of specification exceptions */ + if (!is_valid_psw(&psw)) + return -EOPNOTSUPP; + } rc = handle_itdb(vcpu); if (rc) return rc;