[PATCH v3 6/6] KVM: s390: selftests: Add selftest for single-stepping

Ilya Leoshkevich
2023-07-24T09:50:41Z

Test different variations of single-stepping into interrupts:

- SVC and PGM interrupts;
- Interrupts generated by ISKE;
- Interrupts generated by instructions emulated by KVM;
- Interrupts generated by instructions emulated by userspace.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../testing/selftests/kvm/s390x/debug_test.c | 160 ++++++++++++++++++
2 files changed, 161 insertions(+)
create mode 100644 tools/testing/selftests/kvm/s390x/debug_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c692cc86e7da..f3306eaa7031 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -166,6 +166,7 @@ TEST_GEN_PROGS_s390x += s390x/resets
TEST_GEN_PROGS_s390x += s390x/sync_regs_test
TEST_GEN_PROGS_s390x += s390x/tprot
TEST_GEN_PROGS_s390x += s390x/cmma_test
+TEST_GEN_PROGS_s390x += s390x/debug_test
TEST_GEN_PROGS_s390x += demand_paging_test
TEST_GEN_PROGS_s390x += dirty_log_test
TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
diff --git a/tools/testing/selftests/kvm/s390x/debug_test.c b/tools/testing/selftests/kvm/s390x/debug_test.c
new file mode 100644
index 000000000000..a8fa9fe93b3c
--- /dev/null
+++ b/tools/testing/selftests/kvm/s390x/debug_test.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Test KVM debugging features. */
+#include "kvm_util.h"
+#include "test_util.h"
+
+#include <linux/kvm.h>
+
+#define __LC_SVC_NEW_PSW 0x1c0
+#define __LC_PGM_NEW_PSW 0x1d0
+#define ICPT_INSTRUCTION 0x04
+#define IPA0_DIAG 0x8300
+#define PGM_SPECIFICATION 0x06
+
+/* Common code for testing single-stepping interruptions. */
+extern char int_handler[];
+asm("int_handler:\n"
+ "j .\n");
+
+static struct kvm_vm *test_step_int_1(struct kvm_vcpu **vcpu, void *guest_code,
+ size_t new_psw_off, uint64_t *new_psw)
+{
+ struct kvm_guest_debug debug = {};
+ struct kvm_regs regs;
+ struct kvm_vm *vm;
+ char *lowcore;
+
+ vm = vm_create_with_one_vcpu(vcpu, guest_code);
+ lowcore = addr_gpa2hva(vm, 0);
+ new_psw[0] = (*vcpu)->run->psw_mask;
+ new_psw[1] = (uint64_t)int_handler;
+ memcpy(lowcore + new_psw_off, new_psw, 16);
+ vcpu_regs_get(*vcpu, &regs);
+ regs.gprs[2] = -1;
+ vcpu_regs_set(*vcpu, &regs);
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+ vcpu_guest_debug_set(*vcpu, &debug);
+ vcpu_run(*vcpu);
+
+ return vm;
+}
+
+static void test_step_int(void *guest_code, size_t new_psw_off)
+{
+ struct kvm_vcpu *vcpu;
+ uint64_t new_psw[2];
+ struct kvm_vm *vm;
+
+ vm = test_step_int_1(&vcpu, guest_code, new_psw_off, new_psw);
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_DEBUG);
+ ASSERT_EQ(vcpu->run->psw_mask, new_psw[0]);
+ ASSERT_EQ(vcpu->run->psw_addr, new_psw[1]);
+ kvm_vm_free(vm);
+}
+
+/* Test single-stepping "boring" program interruptions. */
+extern char test_step_pgm_guest_code[];
+asm("test_step_pgm_guest_code:\n"
+ ".insn rr,0x1d00,%r1,%r0 /* dr %r1,%r0 */\n"
+ "j .\n");
+
+static void test_step_pgm(void)
+{
+ test_step_int(test_step_pgm_guest_code, __LC_PGM_NEW_PSW);
+}
+
+/*
+ * Test single-stepping program interruptions caused by DIAG.
+ * Userspace emulation must not interfere with single-stepping.
+ */
+extern char test_step_pgm_diag_guest_code[];
+asm("test_step_pgm_diag_guest_code:\n"
+ "diag %r0,%r0,0\n"
+ "j .\n");
+
+static void test_step_pgm_diag(void)
+{
+ struct kvm_s390_irq irq = {
+ .type = KVM_S390_PROGRAM_INT,
+ .u.pgm.code = PGM_SPECIFICATION,
+ };
+ struct kvm_vcpu *vcpu;
+ uint64_t new_psw[2];
+ struct kvm_vm *vm;
+
+ vm = test_step_int_1(&vcpu, test_step_pgm_diag_guest_code,
+ __LC_PGM_NEW_PSW, new_psw);
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_S390_SIEIC);
+ ASSERT_EQ(vcpu->run->s390_sieic.icptcode, ICPT_INSTRUCTION);
+ ASSERT_EQ(vcpu->run->s390_sieic.ipa & 0xff00, IPA0_DIAG);
+ vcpu_ioctl(vcpu, KVM_S390_IRQ, &irq);
+ vcpu_run(vcpu);
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_DEBUG);
+ ASSERT_EQ(vcpu->run->psw_mask, new_psw[0]);
+ ASSERT_EQ(vcpu->run->psw_addr, new_psw[1]);
+ kvm_vm_free(vm);
+}
+
+/*
+ * Test single-stepping program interruptions caused by ISKE.
+ * CPUSTAT_KSS handling must not interfere with single-stepping.
+ */
+extern char test_step_pgm_iske_guest_code[];
+asm("test_step_pgm_iske_guest_code:\n"
+ "iske %r2,%r2\n"
+ "j .\n");
+
+static void test_step_pgm_iske(void)
+{
+ test_step_int(test_step_pgm_iske_guest_code, __LC_PGM_NEW_PSW);
+}
+
+/*
+ * Test single-stepping program interruptions caused by LCTL.
+ * KVM emulation must not interfere with single-stepping.
+ */
+extern char test_step_pgm_lctl_guest_code[];
+asm("test_step_pgm_lctl_guest_code:\n"
+ "lctl %c0,%c0,1\n"
+ "j .\n");
+
+static void test_step_pgm_lctl(void)
+{
+ test_step_int(test_step_pgm_lctl_guest_code, __LC_PGM_NEW_PSW);
+}
+
+/* Test single-stepping supervisor-call interruptions. */
+extern char test_step_svc_guest_code[];
+asm("test_step_svc_guest_code:\n"
+ "svc 0\n"
+ "j .\n");
+
+static void test_step_svc(void)
+{
+ test_step_int(test_step_svc_guest_code, __LC_SVC_NEW_PSW);
+}
+
+/* Run all tests above. */
+static struct testdef {
+ const char *name;
+ void (*test)(void);
+} testlist[] = {
+ { "single-step pgm", test_step_pgm },
+ { "single-step pgm caused by diag", test_step_pgm_diag },
+ { "single-step pgm caused by iske", test_step_pgm_iske },
+ { "single-step pgm caused by lctl", test_step_pgm_lctl },
+ { "single-step svc", test_step_svc },
+};
+
+int main(int argc, char *argv[])
+{
+ int idx;
+
+ ksft_print_header();
+ ksft_set_plan(ARRAY_SIZE(testlist));
+ for (idx = 0; idx < ARRAY_SIZE(testlist); idx++) {
+ testlist[idx].test();
+ ksft_test_result_pass("%s\n", testlist[idx].name);
+ }
+ ksft_finished();
+}
--
2.41.0