Message ID | 20230724094716.91510-2-iii@linux.ibm.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | KVM: s390: interrupt: Fix stepping into interrupt handlers | expand |
On Mon, 24 Jul 2023 11:44:07 +0200 Ilya Leoshkevich <iii@linux.ibm.com> wrote: > After single-stepping an instruction that generates an interrupt, GDB > ends up on the second instruction of the respective interrupt handler. > > The reason is that vcpu_pre_run() manually delivers the interrupt, and > then __vcpu_run() runs the first handler instruction using the > CPUSTAT_P flag. This causes a KVM_SINGLESTEP exit on the second handler > instruction. > > Fix by delaying the KVM_SINGLESTEP exit until after the manual > interrupt delivery. > > Acked-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > arch/s390/kvm/interrupt.c | 14 ++++++++++++++ > arch/s390/kvm/kvm-s390.c | 4 ++-- > 2 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index 9bd0a873f3b1..85e39f472bb4 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -1392,6 +1392,7 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu) > { > struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; > int rc = 0; > + bool delivered = false; > unsigned long irq_type; > unsigned long irqs; > > @@ -1465,6 +1466,19 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu) > WARN_ONCE(1, "Unknown pending irq type %ld", irq_type); > clear_bit(irq_type, &li->pending_irqs); > } > + delivered |= !rc; > + } > + > + /* > + * We delivered at least one interrupt and modified the PC. Force a > + * singlestep event now. > + */ > + if (delivered && guestdbg_sstep_enabled(vcpu)) { > + struct kvm_debug_exit_arch *debug_exit = &vcpu->run->debug.arch; > + > + debug_exit->addr = vcpu->arch.sie_block->gpsw.addr; > + debug_exit->type = KVM_SINGLESTEP; > + vcpu->guest_debug |= KVM_GUESTDBG_EXIT_PENDING; > } > > set_intercept_indicators(vcpu); > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index d1e768bcfe1d..0c6333b108ba 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -4611,7 +4611,7 @@ static int vcpu_pre_run(struct kvm_vcpu *vcpu) > > if (!kvm_is_ucontrol(vcpu->kvm)) { > rc = kvm_s390_deliver_pending_interrupts(vcpu); > - if (rc) > + if (rc || guestdbg_exit_pending(vcpu)) > return rc; > } > > @@ -4738,7 +4738,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) > > do { > rc = vcpu_pre_run(vcpu); > - if (rc) > + if (rc || guestdbg_exit_pending(vcpu)) > break; > > kvm_vcpu_srcu_read_unlock(vcpu);
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 9bd0a873f3b1..85e39f472bb4 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1392,6 +1392,7 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu) { struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int; int rc = 0; + bool delivered = false; unsigned long irq_type; unsigned long irqs; @@ -1465,6 +1466,19 @@ int __must_check kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu) WARN_ONCE(1, "Unknown pending irq type %ld", irq_type); clear_bit(irq_type, &li->pending_irqs); } + delivered |= !rc; + } + + /* + * We delivered at least one interrupt and modified the PC. Force a + * singlestep event now. + */ + if (delivered && guestdbg_sstep_enabled(vcpu)) { + struct kvm_debug_exit_arch *debug_exit = &vcpu->run->debug.arch; + + debug_exit->addr = vcpu->arch.sie_block->gpsw.addr; + debug_exit->type = KVM_SINGLESTEP; + vcpu->guest_debug |= KVM_GUESTDBG_EXIT_PENDING; } set_intercept_indicators(vcpu); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index d1e768bcfe1d..0c6333b108ba 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4611,7 +4611,7 @@ static int vcpu_pre_run(struct kvm_vcpu *vcpu) if (!kvm_is_ucontrol(vcpu->kvm)) { rc = kvm_s390_deliver_pending_interrupts(vcpu); - if (rc) + if (rc || guestdbg_exit_pending(vcpu)) return rc; } @@ -4738,7 +4738,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) do { rc = vcpu_pre_run(vcpu); - if (rc) + if (rc || guestdbg_exit_pending(vcpu)) break; kvm_vcpu_srcu_read_unlock(vcpu);