Certain CPU instructions will cause an exit of the virtual
machine. Run some of these instructions to check whether
they are emulated right by KVM (or QEMU).
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
---
Note: Test have been verified to pass with KVM of a 4.11 kernel.
Running the tests with QEMU TCG emulation does not work yet ...
QEMU first requires a bunch of fixes before this can pass there.
v2:
- Added entry in s390x/unittests.cfg
- Use low-core GEN_LC_STFL definition instead of hard-coded magic value
- Added lots of exception tests (thanks to David's interrupt framework!)
- Fixed constraints of inline assembler
(I haven't added a timing/iteration infrastructure like Paolo suggested
yet - will do that later once the basic tests have been accepted)
lib/s390x/asm/interrupt.h | 1 +
lib/s390x/interrupt.c | 5 ++
s390x/Makefile | 1 +
s390x/intercept.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
5 files changed, 180 insertions(+)
create mode 100644 s390x/intercept.c
diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
index 383d312..926f858 100644
--- a/lib/s390x/asm/interrupt.h
+++ b/lib/s390x/asm/interrupt.h
@@ -14,5 +14,6 @@
void handle_pgm_int(void);
void expect_pgm_int(void);
void check_pgm_int_code(uint16_t code);
+uint16_t get_pgm_int_code(void);
#endif
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 8d861a2..b5cc7ce 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -23,6 +23,11 @@ void expect_pgm_int(void)
mb();
}
+uint16_t get_pgm_int_code(void)
+{
+ return lc->pgm_int_code;
+}
+
void check_pgm_int_code(uint16_t code)
{
mb();
diff --git a/s390x/Makefile b/s390x/Makefile
index b48f8ab..a61e163 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -1,4 +1,5 @@
tests = $(TEST_DIR)/selftest.elf
+tests += $(TEST_DIR)/intercept.elf
all: directories test_cases
diff --git a/s390x/intercept.c b/s390x/intercept.c
new file mode 100644
index 0000000..4e3fb57
--- /dev/null
+++ b/s390x/intercept.c
@@ -0,0 +1,170 @@
+/*
+ * Interception tests - for s390x CPU instruction that cause a VM exit
+ *
+ * Copyright (c) 2017 Red Hat Inc
+ *
+ * Authors:
+ * Thomas Huth <thuth@xxxxxxxxxx>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License version 2.
+ */
+#include <libcflat.h>
+#include <asm/asm-offsets.h>
+#include <asm/interrupt.h>
+#include <asm/page.h>
+
+static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE)));
+
+/* Enable or disable low-address protection */
+static void set_low_prot(bool enable)
+{
+ uint64_t cr0;
+
+ asm volatile (" stctg 0,0,%0 " : : "Q"(cr0));
+ if (enable)
+ cr0 |= 1ULL << (63-35);
+ else
+ cr0 &= ~(1ULL << (63-35));
+ asm volatile (" lctlg 0,0,%0 " : : "Q"(cr0));
+}
+
+/* Test the SET PREFIX and STORE PREFIX instructions */
+static void test_prefix(void)
+{
+ uint32_t old_prefix = -1U, tst_prefix = -1U;
+ uint32_t new_prefix = (uint32_t)(intptr_t)pagebuf;
+
+ memset(pagebuf, 0, PAGE_SIZE * 2);
+
+ /*
+ * Temporarily change the prefix page to our buffer, and store
+ * some facility bits there ... at least some of them should be
+ * set in our buffer afterwards.
+ */
+ asm volatile (
+ " stpx %0\n"
+ " spx %2\n"
+ " stfl 0\n"
+ " stpx %1\n"
+ " spx %0\n"
+ : "+Q"(old_prefix), "+Q"(tst_prefix)
+ : "Q"(new_prefix)
+ : "memory");
+ report("spx + stfl", pagebuf[GEN_LC_STFL] != 0 &&
+ old_prefix == 0 && tst_prefix == new_prefix);
+
+ expect_pgm_int();
+ asm volatile(" spx 0(%0) " : : "r"(1));
+ report("spx alignment",
+ get_pgm_int_code() == PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile(" spx 0(%0) " : : "r"(-8));
+ report("spx addressing",
+ get_pgm_int_code() == PGM_INT_CODE_ADDRESSING);
+
+ expect_pgm_int();
+ set_low_prot(true);
+ asm volatile(" stpx 0(%0) " : : "r"(8));
+ set_low_prot(false);
+ report("stpx low-address protection",
+ get_pgm_int_code() == PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile(" stpx 0(%0) " : : "r"(1));
+ report("stpx alignment",
+ get_pgm_int_code() == PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile(" stpx 0(%0) " : : "r"(-8));
+ report("stpx addressing",
+ get_pgm_int_code() == PGM_INT_CODE_ADDRESSING);
+}
+
+/* Test the STORE CPU ADDRESS instruction */
+static void test_stap(void)
+{
+ uint16_t cpuid = 0xffff;
+
+ asm volatile ("stap %0\n" : "+Q"(cpuid));
+ report("get cpu id", cpuid != 0xffff);
+
+ expect_pgm_int();
+ set_low_prot(true);
+ asm volatile ("stap 0(%0)\n" : : "r"(8));
+ set_low_prot(false);
+ report("low-address protection",
+ get_pgm_int_code() == PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile ("stap 0(%0)\n" : : "r"(1));
+ report("alignment", get_pgm_int_code() == PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile ("stap 0(%0)\n" : : "r"(-8));
+ report("addressing", get_pgm_int_code() == PGM_INT_CODE_ADDRESSING);
+}
+
+/* Test the TEST BLOCK instruction */
+static void test_testblock(void)
+{
+ int cc;
+
+ memset(pagebuf, 0xaa, PAGE_SIZE);
+
+ asm volatile (
+ " lghi 0,0\n"
+ " tb %1\n"
+ " ipm %0\n"
+ " srl %0,28\n"
+ : "=d" (cc)
+ : "a"(pagebuf + 0x123)
+ : "memory", "0", "cc");
+ report("page cleared",
+ cc == 0 && pagebuf[0] == 0 && pagebuf[PAGE_SIZE - 1] == 0);
+
+ expect_pgm_int();
+ set_low_prot(true);
+ asm volatile (" tb %0 " : : "r"(4096));
+ set_low_prot(false);
+ report("low-address protection",
+ get_pgm_int_code() == PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile (" tb %0 " : : "r"(-4096));
+ report("addressing", get_pgm_int_code() == PGM_INT_CODE_ADDRESSING);
+}
+
+struct {
+ const char *name;
+ void (*func)(void);
+} tests[] = {
+ { "prefix", test_prefix },
+ { "stap", test_stap },
+ { "testblock", test_testblock },
+ { NULL, NULL }
+};
+
+int main(int argc, char **argv)
+{
+ int all = 0;
+ int i;
+
+ report_prefix_push("intercept");
+
+ if (argc < 2 || (argc == 2 && !strcmp(argv[1], "all")))
+ all = 1;
+
+ for (i = 0; tests[i].name != NULL; i++) {
+ report_prefix_push(tests[i].name);
+ if (all || strcmp(argv[1], tests[i].name) == 0) {
+ tests[i].func();
+ }
+ report_prefix_pop();
+ }
+
+ report_prefix_pop();
+
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 92e01ab..3b6b892 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -22,3 +22,6 @@
file = selftest.elf
groups = selftest
extra_params = -append 'test 123'
+
+[intercept]
+file = intercept.elf
--
1.8.3.1
