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authorIlya Leoshkevich <iii@linux.ibm.com>2023-07-25 16:37:17 +0200
committerJanosch Frank <frankja@linux.ibm.com>2023-08-28 09:24:19 +0000
commit74a439ef7b67d89d29ec7485c3aeca20a64449c5 (patch)
treeaaade94674733cd89121d0fc19e05d22123b3b73 /arch/s390/kvm
parent16631c42e6ff4f5acf30998fda6c2ea09d1adbfe (diff)
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KVM: s390: interrupt: Fix single-stepping into program interrupt handlers
Currently, after single-stepping an instruction that generates a specification exception, GDB ends up on the instruction immediately following it. The reason is that vcpu_post_run() injects the interrupt and sets KVM_GUESTDBG_EXIT_PENDING, causing a KVM_SINGLESTEP exit. The interrupt is not delivered, however, therefore userspace sees the address of the next instruction. Fix by letting the __vcpu_run() loop go into the next iteration, where vcpu_pre_run() delivers the interrupt and sets KVM_GUESTDBG_EXIT_PENDING. Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Message-ID: <20230725143857.228626-3-iii@linux.ibm.com> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Diffstat (limited to 'arch/s390/kvm')
-rw-r--r--arch/s390/kvm/intercept.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 954d39adf85c..e54496740859 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -228,6 +228,21 @@ static int handle_itdb(struct kvm_vcpu *vcpu)
#define per_event(vcpu) (vcpu->arch.sie_block->iprcc & PGM_PER)
+static bool should_handle_per_event(const struct kvm_vcpu *vcpu)
+{
+ if (!guestdbg_enabled(vcpu) || !per_event(vcpu))
+ return false;
+ if (guestdbg_sstep_enabled(vcpu) &&
+ vcpu->arch.sie_block->iprcc != PGM_PER) {
+ /*
+ * __vcpu_run() will exit after delivering the concurrently
+ * indicated condition.
+ */
+ return false;
+ }
+ return true;
+}
+
static int handle_prog(struct kvm_vcpu *vcpu)
{
psw_t psw;
@@ -242,7 +257,7 @@ static int handle_prog(struct kvm_vcpu *vcpu)
if (kvm_s390_pv_cpu_is_protected(vcpu))
return -EOPNOTSUPP;
- if (guestdbg_enabled(vcpu) && per_event(vcpu)) {
+ if (should_handle_per_event(vcpu)) {
rc = kvm_s390_handle_per_event(vcpu);
if (rc)
return rc;