KVM: s390: selftests: Extended user_operexec tests

There is a possibility that the user_operexec capability
only works if facility bit 74 is enabled. This is now fixed,
but add a selftest to demonstrate that.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260507200836.3500368-3-farman@linux.ibm.com>

2 files changed, 116 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/include/s390/facility.h b/tools/testing/selftests/kvm/include/s390/facility.h
index 41a265742666..e5259f63be22 100644
--- a/tools/testing/selftests/kvm/include/s390/facility.h
+++ b/tools/testing/selftests/kvm/include/s390/facility.h
@@ -11,6 +11,7 @@
 #ifndef SELFTEST_KVM_FACILITY_H
 #define SELFTEST_KVM_FACILITY_H
 
+#include <linux/atomic.h>
 #include <linux/bitops.h>
 
 /* alt_stfle_fac_list[16] + stfle_fac_list[16] */
@@ -19,6 +20,11 @@
 extern u64 stfl_doublewords[NB_STFL_DOUBLEWORDS];
 extern bool stfle_flag;
 
+static inline bool clear_bit_inv(unsigned long nr, unsigned long *ptr)
+{
+	return clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
+}
+
 static inline bool test_bit_inv(unsigned long nr, const unsigned long *ptr)
 {
 	return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
diff --git a/tools/testing/selftests/kvm/s390/user_operexec.c b/tools/testing/selftests/kvm/s390/user_operexec.c
index 714906c1d12a..b24c1f9dbbe8 100644
--- a/tools/testing/selftests/kvm/s390/user_operexec.c
+++ b/tools/testing/selftests/kvm/s390/user_operexec.c
@@ -6,6 +6,7 @@
  * Authors:
  *  Janosch Frank <frankja@linux.ibm.com>
  */
+#include "facility.h"
 #include "kselftest.h"
 #include "kvm_util.h"
 #include "test_util.h"
@@ -109,6 +110,111 @@ static void test_user_operexec_combined(void)
 	kvm_vm_free(vm);
 }
 
+static struct kvm_vm *create_vm_without_sthyi(void)
+{
+	struct kvm_s390_vm_cpu_processor info;
+	struct kvm_vm *vm;
+
+	vm = vm_create(1);
+
+	kvm_device_attr_get(vm->fd, KVM_S390_VM_CPU_MODEL,
+			    KVM_S390_VM_CPU_PROCESSOR, &info);
+
+	clear_bit_inv(74, (unsigned long *)&info.fac_list);
+	kvm_device_attr_set(vm->fd, KVM_S390_VM_CPU_MODEL,
+			    KVM_S390_VM_CPU_PROCESSOR, &info);
+
+	return vm;
+}
+
+static void test_user_instr0_no_stfle_74(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int rc;
+
+	vm = create_vm_without_sthyi();
+
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_INSTR0, 0);
+	TEST_ASSERT_EQ(0, rc);
+
+	vcpu = vm_vcpu_add(vm, 0, guest_code_instr0);
+
+	vcpu_run(vcpu);
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_S390_SIEIC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.icptcode, ICPT_OPEREXC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.ipa, 0x0000);
+
+	kvm_vm_free(vm);
+}
+
+static void test_user_operexec_no_stfle_74(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int rc;
+
+	vm = create_vm_without_sthyi();
+
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_OPEREXEC, 0);
+	TEST_ASSERT_EQ(0, rc);
+
+	vcpu = vm_vcpu_add(vm, 0, guest_code_user_operexec);
+
+	vcpu_run(vcpu);
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_S390_SIEIC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.icptcode, ICPT_OPEREXC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.ipa, 0x0807);
+
+	kvm_vm_free(vm);
+}
+
+static void test_instr0_combined_no_stfle_74(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int rc;
+
+	vm = create_vm_without_sthyi();
+
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_INSTR0, 0);
+	TEST_ASSERT_EQ(0, rc);
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_OPEREXEC, 0);
+	TEST_ASSERT_EQ(0, rc);
+
+	vcpu = vm_vcpu_add(vm, 0, guest_code_instr0);
+
+	vcpu_run(vcpu);
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_S390_SIEIC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.icptcode, ICPT_OPEREXC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.ipa, 0x0000);
+
+	kvm_vm_free(vm);
+}
+
+static void test_operexec_combined_no_stfle_74(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int rc;
+
+	vm = create_vm_without_sthyi();
+
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_INSTR0, 0);
+	TEST_ASSERT_EQ(0, rc);
+	rc = __vm_enable_cap(vm, KVM_CAP_S390_USER_OPEREXEC, 0);
+	TEST_ASSERT_EQ(0, rc);
+
+	vcpu = vm_vcpu_add(vm, 0, guest_code_user_operexec);
+
+	vcpu_run(vcpu);
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_S390_SIEIC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.icptcode, ICPT_OPEREXC);
+	TEST_ASSERT_EQ(vcpu->run->s390_sieic.ipa, 0x0807);
+
+	kvm_vm_free(vm);
+}
+
 /*
  * Run all tests above.
  *
@@ -122,6 +228,10 @@ static struct testdef {
 	{ "instr0", test_user_instr0 },
 	{ "operexec", test_user_operexec },
 	{ "operexec_combined", test_user_operexec_combined},
+	{ "instr0_no_stfle_74", test_user_instr0_no_stfle_74 },
+	{ "instr0_combined_no_stfle_74", test_instr0_combined_no_stfle_74 },
+	{ "operexec_combined_no_stfle_74", test_operexec_combined_no_stfle_74 },
+	{ "operexec_no_stfle_74", test_user_operexec_no_stfle_74 },
 };
 
 int main(int argc, char *argv[])