From 16631c42e6ff4f5acf30998fda6c2ea09d1adbfe Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Tue, 25 Jul 2023 16:37:16 +0200 Subject: [PATCH] KVM: s390: interrupt: Fix single-stepping into interrupt handlers 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 Reviewed-by: Claudio Imbrenda Signed-off-by: Ilya Leoshkevich Message-ID: <20230725143857.228626-2-iii@linux.ibm.com> Signed-off-by: Claudio Imbrenda Signed-off-by: Janosch Frank --- 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); -- 2.20.1