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Message-ID: <20230721120046.2262291-2-iii@linux.ibm.com>
Date: Fri, 21 Jul 2023 13:57:54 +0200
From: Ilya Leoshkevich <iii@...ux.ibm.com>
To: Christian Borntraeger <borntraeger@...ux.ibm.com>,
Janosch Frank <frankja@...ux.ibm.com>,
Claudio Imbrenda <imbrenda@...ux.ibm.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>
Cc: David Hildenbrand <david@...hat.com>,
Sven Schnelle <svens@...ux.ibm.com>, kvm@...r.kernel.org,
linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
Jens Freimann <jfreimann@...hat.com>,
Ilya Leoshkevich <iii@...ux.ibm.com>
Subject: [PATCH v2 1/6] 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.
Signed-off-by: Ilya Leoshkevich <iii@...ux.ibm.com>
---
arch/s390/kvm/interrupt.c | 10 ++++++++++
arch/s390/kvm/kvm-s390.c | 4 ++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 9bd0a873f3b1..2cebe4227b8e 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 +1466,15 @@ 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;
+ }
+
+ 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);
--
2.41.0
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