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).
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
---
v4:
- Use %%c0 for lctlg instead of 0
- Replaced "CPU ID" with "CPU address" in the STAP test
lib/s390x/asm/interrupt.h | 20 ++++
s390x/Makefile | 1 +
s390x/intercept.c | 227 ++++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
4 files changed, 251 insertions(+)
create mode 100644 s390x/intercept.c
diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
index 383d312..41be039 100644
--- a/lib/s390x/asm/interrupt.h
+++ b/lib/s390x/asm/interrupt.h
@@ -15,4 +15,24 @@ void handle_pgm_int(void);
void expect_pgm_int(void);
void check_pgm_int_code(uint16_t code);
+/* Activate low-address protection */
+static inline void low_prot_enable(void)
+{
+ uint64_t cr0;
+
+ asm volatile (" stctg %%c0,%%c0,%0 " : : "Q"(cr0) : "memory");
+ cr0 |= 1ULL << (63-35);
+ asm volatile (" lctlg %%c0,%%c0,%0 " : : "Q"(cr0));
+}
+
+/* Disable low-address protection */
+static inline void low_prot_disable(void)
+{
+ uint64_t cr0;
+
+ asm volatile (" stctg %%c0,%%c0,%0 " : : "Q"(cr0) : "memory");
+ cr0 &= ~(1ULL << (63-35));
+ asm volatile (" lctlg %%c0,%%c0,%0 " : : "Q"(cr0));
+}
+
#endif
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..4558860
--- /dev/null
+++ b/s390x/intercept.c
@@ -0,0 +1,227 @@
+/*
+ * 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 * 2)));
+
+static unsigned long nr_iterations;
+static unsigned long time_to_run;
+
+/* Test the STORE PREFIX instruction */
+static void test_stpx(void)
+{
+ uint32_t old_prefix = -1U, tst_prefix = -1U;
+ uint32_t new_prefix = (uint32_t)(intptr_t)pagebuf;
+
+ /* Can we successfully change the prefix? */
+ asm volatile (
+ " stpx %0\n"
+ " spx %2\n"
+ " stpx %1\n"
+ " spx %0\n"
+ : "+Q"(old_prefix), "+Q"(tst_prefix)
+ : "Q"(new_prefix));
+ report("store prefix", old_prefix == 0 && tst_prefix == new_prefix);
+
+ expect_pgm_int();
+ low_prot_enable();
+ asm volatile(" stpx 0(%0) " : : "r"(8));
+ low_prot_disable();
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile(" stpx 0(%0) " : : "r"(1));
+ check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile(" stpx 0(%0) " : : "r"(-8));
+ check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
+}
+
+/* Test the SET PREFIX instruction */
+static void test_spx(void)
+{
+ uint32_t new_prefix = (uint32_t)(intptr_t)pagebuf;
+ uint32_t old_prefix;
+
+ 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 %1\n"
+ " stfl 0\n"
+ " spx %0\n"
+ : "+Q"(old_prefix)
+ : "Q"(new_prefix)
+ : "memory");
+ report("stfl to new prefix", pagebuf[GEN_LC_STFL] != 0);
+
+ expect_pgm_int();
+ asm volatile(" spx 0(%0) " : : "r"(1));
+ check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile(" spx 0(%0) " : : "r"(-8));
+ check_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 address", cpuid != 0xffff);
+
+ expect_pgm_int();
+ low_prot_enable();
+ asm volatile ("stap 0(%0)\n" : : "r"(8));
+ low_prot_disable();
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile ("stap 0(%0)\n" : : "r"(1));
+ check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
+
+ expect_pgm_int();
+ asm volatile ("stap 0(%0)\n" : : "r"(-8));
+ check_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 %%r0,0\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();
+ low_prot_enable();
+ asm volatile (" tb %0 " : : "r"(4096));
+ low_prot_disable();
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+
+ expect_pgm_int();
+ asm volatile (" tb %0 " : : "r"(-4096));
+ check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
+}
+
+static uint64_t get_clock_ms(void)
+{
+ uint64_t clk;
+
+ asm volatile(" stck %0 " : : "Q"(clk) : "memory");
+
+ /* Bit 51 is incrememented each microsecond */
+ return (clk >> (63 - 51)) / 1000;
+}
+
+struct {
+ const char *name;
+ void (*func)(void);
+ bool run_it;
+} tests[] = {
+ { "stpx", test_stpx, false },
+ { "spx", test_spx, false },
+ { "stap", test_stap, false },
+ { "testblock", test_testblock, false },
+ { NULL, NULL, false }
+};
+
+void parse_intercept_test_args(int argc, char **argv)
+{
+ int i, ti;
+ bool run_all = true;
+
+ for (i = 1; i < argc; i++) {
+ if (!strcmp("-i", argv[i])) {
+ i++;
+ if (i >= argc)
+ report_abort("-i needs a parameter");
+ nr_iterations = atol(argv[i]);
+ } else if (!strcmp("-t", argv[i])) {
+ i++;
+ if (i >= argc)
+ report_abort("-t needs a parameter");
+ time_to_run = atol(argv[i]);
+ } else for (ti = 0; tests[ti].name != NULL; ti++) {
+ if (!strcmp(tests[ti].name, argv[i])) {
+ run_all = false;
+ tests[ti].run_it = true;
+ break;
+ } else if (tests[ti + 1].name == NULL) {
+ report_abort("Unsupported parameter '%s'",
+ argv[i]);
+ }
+ }
+ }
+
+ if (run_all) {
+ for (ti = 0; tests[ti].name != NULL; ti++)
+ tests[ti].run_it = true;
+ }
+}
+
+int main(int argc, char **argv)
+{
+ uint64_t startclk;
+ int ti;
+
+ parse_intercept_test_args(argc, argv);
+
+ if (nr_iterations == 0 && time_to_run == 0)
+ nr_iterations = 1;
+
+ report_prefix_push("intercept");
+
+ startclk = get_clock_ms();
+ for (;;) {
+ for (ti = 0; tests[ti].name != NULL; ti++) {
+ report_prefix_push(tests[ti].name);
+ if (tests[ti].run_it)
+ tests[ti].func();
+ report_prefix_pop();
+ }
+ if (nr_iterations) {
+ nr_iterations -= 1;
+ if (nr_iterations == 0)
+ break;
+ }
+ if (time_to_run) {
+ if (get_clock_ms() - startclk > time_to_run)
+ break;
+ }
+ }
+
+ 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
