[kvm-unit-tests PATCH v2 2/2] s390x: Add specification exception interception test

[Janis Schoetterl-Glausch <scgl@linux.ibm.com>]

Check that specification exceptions cause intercepts when
specification exception interpretation is off.
Check that specification exceptions caused by program new PSWs
cause interceptions.
We cannot assert that non program new PSW specification exceptions
are interpreted because whether interpretation occurs or not is
configuration dependent.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 s390x/Makefile             |  2 +
 lib/s390x/sie.h            |  1 +
 s390x/snippets/c/spec_ex.c | 20 +++++++++
 s390x/spec_ex-sie.c        | 83 ++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg        |  3 ++
 5 files changed, 109 insertions(+)
 create mode 100644 s390x/snippets/c/spec_ex.c
 create mode 100644 s390x/spec_ex-sie.c

diff --git a/s390x/Makefile b/s390x/Makefile
index ef8041a..7198882 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -24,6 +24,7 @@ tests += $(TEST_DIR)/mvpg.elf
 tests += $(TEST_DIR)/uv-host.elf
 tests += $(TEST_DIR)/edat.elf
 tests += $(TEST_DIR)/mvpg-sie.elf
+tests += $(TEST_DIR)/spec_ex-sie.elf
 
 tests_binary = $(patsubst %.elf,%.bin,$(tests))
 ifneq ($(HOST_KEY_DOCUMENT),)
@@ -85,6 +86,7 @@ snippet_asmlib = $(SNIPPET_DIR)/c/cstart.o
 # perquisites (=guests) for the snippet hosts.
 # $(TEST_DIR)/<snippet-host>.elf: snippets = $(SNIPPET_DIR)/<c/asm>/<snippet>.gbin
 $(TEST_DIR)/mvpg-sie.elf: snippets = $(SNIPPET_DIR)/c/mvpg-snippet.gbin
+$(TEST_DIR)/spec_ex-sie.elf: snippets = $(SNIPPET_DIR)/c/spec_ex.gbin
 
 $(SNIPPET_DIR)/asm/%.gbin: $(SNIPPET_DIR)/asm/%.o $(FLATLIBS)
 	$(OBJCOPY) -O binary $(patsubst %.gbin,%.o,$@) $@
diff --git a/lib/s390x/sie.h b/lib/s390x/sie.h
index ca514ef..7ef7251 100644
--- a/lib/s390x/sie.h
+++ b/lib/s390x/sie.h
@@ -98,6 +98,7 @@ struct kvm_s390_sie_block {
 	uint8_t		fpf;			/* 0x0060 */
 #define ECB_GS		0x40
 #define ECB_TE		0x10
+#define ECB_SPECI	0x08
 #define ECB_SRSI	0x04
 #define ECB_HOSTPROTINT	0x02
 	uint8_t		ecb;			/* 0x0061 */
diff --git a/s390x/snippets/c/spec_ex.c b/s390x/snippets/c/spec_ex.c
new file mode 100644
index 0000000..bdba4f4
--- /dev/null
+++ b/s390x/snippets/c/spec_ex.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * © Copyright IBM Corp. 2021
+ *
+ * Snippet used by specification exception interception test.
+ */
+#include <stdint.h>
+#include <asm/arch_def.h>
+
+__attribute__((section(".text"))) int main(void)
+{
+	struct lowcore *lowcore = (struct lowcore *) 0;
+	uint64_t bad_psw = 0;
+
+	/* PSW bit 12 has no name or meaning and must be 0 */
+	lowcore->pgm_new_psw.mask = 1UL << (63 - 12);
+	lowcore->pgm_new_psw.addr = 0xdeadbeee;
+	asm volatile ("lpsw %0" :: "Q"(bad_psw));
+	return 0;
+}
diff --git a/s390x/spec_ex-sie.c b/s390x/spec_ex-sie.c
new file mode 100644
index 0000000..b7e79de
--- /dev/null
+++ b/s390x/spec_ex-sie.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * © Copyright IBM Corp. 2021
+ *
+ * Specification exception interception test.
+ * Checks that specification exception interceptions occur as expected when
+ * specification exception interpretation is off/on.
+ */
+#include <libcflat.h>
+#include <sclp.h>
+#include <asm/page.h>
+#include <asm/arch_def.h>
+#include <alloc_page.h>
+#include <vm.h>
+#include <sie.h>
+
+static struct vm vm;
+extern const char _binary_s390x_snippets_c_spec_ex_gbin_start[];
+extern const char _binary_s390x_snippets_c_spec_ex_gbin_end[];
+
+static void setup_guest(void)
+{
+	char *guest;
+	int binary_size = ((uintptr_t)_binary_s390x_snippets_c_spec_ex_gbin_end -
+			   (uintptr_t)_binary_s390x_snippets_c_spec_ex_gbin_start);
+
+	setup_vm();
+	guest = alloc_pages(8);
+	memcpy(guest, _binary_s390x_snippets_c_spec_ex_gbin_start, binary_size);
+	sie_guest_create(&vm, (uint64_t) guest, HPAGE_SIZE);
+}
+
+static void reset_guest(void)
+{
+	vm.sblk->gpsw.addr = PAGE_SIZE * 4;
+	vm.sblk->gpsw.mask = PSW_MASK_64;
+	vm.sblk->icptcode = 0;
+}
+
+static void test_spec_ex_sie(void)
+{
+	setup_guest();
+
+	report_prefix_push("SIE spec ex interpretation");
+	report_prefix_push("off");
+	reset_guest();
+	sie(&vm);
+	/* interpretation off -> initial exception must cause interception */
+	report(vm.sblk->icptcode == ICPT_PROGI
+	       && vm.sblk->iprcc == PGM_INT_CODE_SPECIFICATION
+	       && vm.sblk->gpsw.addr != 0xdeadbeee,
+	       "Received specification exception intercept for initial exception");
+	report_prefix_pop();
+
+	report_prefix_push("on");
+	vm.sblk->ecb |= ECB_SPECI;
+	reset_guest();
+	sie(&vm);
+	/* interpretation on -> configuration dependent if initial exception causes
+	 * interception, but invalid new program PSW must
+	 */
+	report(vm.sblk->icptcode == ICPT_PROGI
+	       && vm.sblk->iprcc == PGM_INT_CODE_SPECIFICATION,
+	       "Received specification exception intercept");
+	if (vm.sblk->gpsw.addr == 0xdeadbeee)
+		report_info("Interpreted initial exception, intercepted invalid program new PSW exception");
+	else
+		report_info("Did not interpret initial exception");
+	report_prefix_pop();
+	report_prefix_pop();
+}
+
+int main(int argc, char **argv)
+{
+	if (!sclp_facilities.has_sief2) {
+		report_skip("SIEF2 facility unavailable");
+		goto out;
+	}
+
+	test_spec_ex_sie();
+out:
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 9e1802f..3b454b7 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -109,3 +109,6 @@ file = edat.elf
 
 [mvpg-sie]
 file = mvpg-sie.elf
+
+[spec_ex-sie]
+file = spec_ex-sie.elf
-- 
2.31.1