[PATCH v2] KVM: s390: selftests: Add load psw bear test

[Janosch Frank <frankja@linux.ibm.com>]

The bear is set for lpsw and lpswe, so let's check that also happens
when kvm emulates these instructions.

Load PSW and all of its variants are only emulated by KVM if there's a
pending machine check. Therefore the tests inject those but never open
the masks to receive them.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 tools/testing/selftests/kvm/Makefile.kvm |   1 +
 tools/testing/selftests/kvm/s390/bear.c  | 133 +++++++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/s390/bear.c

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 6471fa214a9f..9afb6479dbee 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -207,6 +207,7 @@ TEST_GEN_PROGS_s390 += s390/user_operexec
 TEST_GEN_PROGS_s390 += s390/keyop
 TEST_GEN_PROGS_s390 += rseq_test
 TEST_GEN_PROGS_s390 += s390/irq_routing
+TEST_GEN_PROGS_s390 += s390/bear
 
 TEST_GEN_PROGS_riscv = $(TEST_GEN_PROGS_COMMON)
 TEST_GEN_PROGS_riscv += riscv/sbi_pmu_test
diff --git a/tools/testing/selftests/kvm/s390/bear.c b/tools/testing/selftests/kvm/s390/bear.c
new file mode 100644
index 000000000000..c7604176cf65
--- /dev/null
+++ b/tools/testing/selftests/kvm/s390/bear.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* LPSW/E bear tests. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "kselftest.h"
+#include "ucall_common.h"
+#include "facility.h"
+#include "processor.h"
+
+static void guest_lpswe(void)
+{
+	extern void lpswe_dest_addr(void);
+	u64 psw[2] = {0x0400000180000000ULL, (uintptr_t)lpswe_dest_addr};
+	u64 bear;
+
+	asm volatile (
+		"	larl	%%r3,lpswe_addr\n"
+		"lpswe_addr:\n"
+		"       lpswe    %[psw]\n"
+		"       nop\n"
+		"       nop\n"
+		".globl lpswe_dest_addr\n"
+		"lpswe_dest_addr:\n"
+		"       .insn   s,0xb2010000,%[bear]\n"
+		"	lg	%%r4, %[bear]\n"
+		"       nop\n"
+		"       nop\n"
+		: [bear] "=Q" (bear)
+		: [psw] "Q" (psw)
+		: "cc", "r3", "r4"
+		);
+}
+
+static void guest_lpsw(void)
+{
+	extern void lpsw_dest_addr(void);
+	u64 psw_short = (0x0400000180000000ULL | BIT(63 - 12) |
+			 (uintptr_t)lpsw_dest_addr);
+	u64 bear;
+
+	asm volatile (
+		"	larl	%%r3,lpsw_addr\n"
+		"lpsw_addr:\n"
+		"       lpsw    %[psw]\n"
+		"       nop\n"
+		"       nop\n"
+		".globl lpsw_dest_addr\n"
+		"lpsw_dest_addr:\n"
+		"       .insn   s,0xb2010000,%[bear]\n"
+		"	lg	%%r4, %[bear]\n"
+		"       nop\n"
+		"       nop\n"
+		: [bear] "=Q" (bear)
+		: [psw] "Q" (psw_short)
+		: "cc", "r3", "r4"
+		);
+}
+
+/* A machine check forces KVM to emulate PSW loading */
+static void inject_mcheck(struct kvm_vcpu *vcpu)
+{
+	struct kvm_s390_irq irq = {};
+	int irqs;
+
+	irq.type = KVM_S390_MCHK;
+	/* External damage mcheck */
+	irq.u.mchk.cr14 = BIT(63 - 38);
+	irq.u.mchk.mcic = BIT(58);
+	irqs = __vcpu_ioctl(vcpu, KVM_S390_IRQ, &irq);
+	TEST_ASSERT(irqs >= 0, "Error injecting MCHECK errno %d", errno);
+}
+
+static void test_lpswe(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_lpswe);
+	inject_mcheck(vcpu);
+	run = vcpu->run;
+	vcpu_run(vcpu);
+	ksft_test_result(run->s.regs.gprs[3] == run->s.regs.gprs[4],
+			 "emulation: lpswe bear matches\n");
+	kvm_vm_free(vm);
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_lpsw);
+	run = vcpu->run;
+	vcpu_run(vcpu);
+	ksft_test_result(run->s.regs.gprs[3] &&
+			 run->s.regs.gprs[3] == run->s.regs.gprs[4],
+			 "interpretation: lpswe bear matches\n");
+	kvm_vm_free(vm);
+}
+
+static void test_lpsw(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_lpsw);
+	inject_mcheck(vcpu);
+	run = vcpu->run;
+	vcpu_run(vcpu);
+	ksft_test_result(run->s.regs.gprs[3] == run->s.regs.gprs[4],
+			 "emulation: lpsw bear matches\n");
+	kvm_vm_free(vm);
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_lpsw);
+	run = vcpu->run;
+	vcpu_run(vcpu);
+	ksft_test_result(run->s.regs.gprs[3] &&
+			 run->s.regs.gprs[3] == run->s.regs.gprs[4],
+			 "interpretation: lpsw bear matches\n");
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+	TEST_REQUIRE(test_facility(193));
+
+	ksft_print_header();
+	ksft_set_plan(4);
+	test_lpsw();
+	test_lpswe();
+	ksft_finished();
+}
-- 
2.51.0