[kvm-unit-tests PATCH v2 2/2] s390x: mvpg: simple test

Claudio Imbrenda
2021-02-23T14:25:53Z

A simple unit test for the MVPG instruction.

The timeout is set to 10 seconds because the test should complete in a
fraction of a second even on busy machines. If the test is run in VSIE
and the host of the host is not handling MVPG properly, the test will
probably hang.

Testing MVPG behaviour in VSIE is the main motivation for this test.

Anything related to storage keys is not tested.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
---
s390x/Makefile | 1 +
s390x/mvpg.c | 266 ++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 4 +
3 files changed, 271 insertions(+)
create mode 100644 s390x/mvpg.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 08d85c9f..770eaa0b 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -20,6 +20,7 @@ tests += $(TEST_DIR)/sclp.elf
tests += $(TEST_DIR)/css.elf
tests += $(TEST_DIR)/uv-guest.elf
tests += $(TEST_DIR)/sie.elf
+tests += $(TEST_DIR)/mvpg.elf

tests_binary = $(patsubst %.elf,%.bin,$(tests))
ifneq ($(HOST_KEY_DOCUMENT),)
diff --git a/s390x/mvpg.c b/s390x/mvpg.c
new file mode 100644
index 00000000..7a89a462
--- /dev/null
+++ b/s390x/mvpg.c
@@ -0,0 +1,266 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Move Page instruction tests
+ *
+ * Copyright (c) 2020 IBM Corp
+ *
+ * Authors:
+ * Claudio Imbrenda <imbrenda@linux.ibm.com>
+ */
+#include <libcflat.h>
+#include <asm/asm-offsets.h>
+#include <asm-generic/barrier.h>
+#include <asm/interrupt.h>
+#include <asm/pgtable.h>
+#include <mmu.h>
+#include <asm/page.h>
+#include <asm/facility.h>
+#include <asm/mem.h>
+#include <asm/sigp.h>
+#include <smp.h>
+#include <alloc_page.h>
+#include <bitops.h>
+
+/* Used to build the appropriate test values for register 0 */
+#define KFC(x) ((x) << 10)
+#define CCO 0x100
+
+/* How much memory to allocate for the test */
+#define MEM_ORDER 12
+/* How many iterations to perform in the loops */
+#define ITER 8
+
+/* Used to generate the simple pattern */
+#define MAGIC 42
+
+static uint8_t source[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+static uint8_t buffer[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+
+/* Keep track of fresh memory */
+static uint8_t *fresh;
+
+static inline int mvpg(unsigned long r0, void *dest, void *src)
+{
+ register unsigned long reg0 asm ("0") = r0;
+ int cc;
+
+ asm volatile(" mvpg %1,%2\n"
+ " ipm %0\n"
+ " srl %0,28"
+ : "=&d" (cc) : "a" (dest), "a" (src), "d" (reg0)
+ : "memory", "cc");
+ return cc;
+}
+
+/*
+ * Initialize a page with a simple pattern
+ */
+static void init_page(uint8_t *p)
+{
+ int i;
+
+ for (i = 0; i < PAGE_SIZE; i++)
+ p[i] = i + MAGIC;
+}
+
+/*
+ * Check if the given page contains the simple pattern
+ */
+static int page_ok(const uint8_t *p)
+{
+ int i;
+
+ for (i = 0; i < PAGE_SIZE; i++)
+ if (p[i] != (uint8_t)(i + MAGIC))
+ return 0;
+ return 1;
+}
+
+static void test_exceptions(void)
+{
+ int i, expected;
+
+ report_prefix_push("exceptions");
+
+ /*
+ * Key Function Control values 4 and 5 are allowed only in supervisor
+ * state, and even then, only if the move-page-and-set-key facility
+ * is present (STFLE bit 149)
+ */
+ report_prefix_push("privileged");
+ if (test_facility(149)) {
+ expected = PGM_INT_CODE_PRIVILEGED_OPERATION;
+ for (i = 4; i < 6; i++) {
+ expect_pgm_int();
+ enter_pstate();
+ mvpg(KFC(i), buffer, source);
+ report(clear_pgm_int() == expected, "Key Function Control value %d", i);
+ }
+ } else {
+ report_skip("Key Function Control value %d", 4);
+ report_skip("Key Function Control value %d", 5);
+ i = 4;
+ }
+ report_prefix_pop();
+
+ /*
+ * Invalid values of the Key Function Control, or setting the
+ * reserved bits, should result in a specification exception
+ */
+ report_prefix_push("specification");
+ expected = PGM_INT_CODE_SPECIFICATION;
+ expect_pgm_int();
+ mvpg(KFC(3), buffer, source);
+ report(clear_pgm_int() == expected, "Key Function Control value 3");
+ for (; i < 32; i++) {
+ expect_pgm_int();
+ mvpg(KFC(i), buffer, source);
+ report(clear_pgm_int() == expected, "Key Function Control value %d", i);
+ }
+ report_prefix_pop();
+
+ /* Operands outside memory result in addressing exceptions, as usual */
+ report_prefix_push("addressing");
+ expected = PGM_INT_CODE_ADDRESSING;
+ expect_pgm_int();
+ mvpg(0, buffer, (void *)PAGE_MASK);
+ report(clear_pgm_int() == expected, "Second operand outside memory");
+
+ expect_pgm_int();
+ mvpg(0, (void *)PAGE_MASK, source);
+ report(clear_pgm_int() == expected, "First operand outside memory");
+ report_prefix_pop();
+
+ report_prefix_pop();
+}
+
+static void test_success(void)
+{
+ int cc;
+
+ report_prefix_push("success");
+ /* Test successful scenarios, both in supervisor and problem state */
+ cc = mvpg(0, buffer, source);
+ report(page_ok(buffer) && !cc, "Supervisor state MVPG successful");
+
+ enter_pstate();
+ cc = mvpg(0, buffer, source);
+ leave_pstate();
+ report(page_ok(buffer) && !cc, "Problem state MVPG successful");
+
+ report_prefix_pop();
+}
+
+static void test_small_loop(const void *string)
+{
+ uint8_t *dest;
+ int i, cc;
+
+ /* Looping over cold and warm pages helps catch VSIE bugs */
+ report_prefix_push(string);
+ dest = fresh;
+ for (i = 0; i < ITER; i++) {
+ cc = mvpg(0, fresh, source);
+ report(page_ok(fresh) && !cc, "cold: %p, %p", source, fresh);
+ fresh += PAGE_SIZE;
+ }
+
+ for (i = 0; i < ITER; i++) {
+ memset(dest, 0, PAGE_SIZE);
+ cc = mvpg(0, dest, source);
+ report(page_ok(dest) && !cc, "warm: %p, %p", source, dest);
+ dest += PAGE_SIZE;
+ }
+ report_prefix_pop();
+}
+
+static void test_mmu_prot(void)
+{
+ int cc;
+
+ report_prefix_push("protection");
+ report_prefix_push("cco=0");
+
+ /* MVPG should still succeed when the source is read-only */
+ protect_page(source, PAGE_ENTRY_P);
+ cc = mvpg(0, fresh, source);
+ report(page_ok(fresh) && !cc, "source read only");
+ unprotect_page(source, PAGE_ENTRY_P);
+ fresh += PAGE_SIZE;
+
+ /*
+ * When the source or destination are invalid, a page translation
+ * exception should be raised; when the destination is read-only,
+ * a protection exception should be raised.
+ */
+ protect_page(fresh, PAGE_ENTRY_P);
+ expect_pgm_int();
+ mvpg(0, fresh, source);
+ report(clear_pgm_int() == PGM_INT_CODE_PROTECTION, "destination read only");
+ fresh += PAGE_SIZE;
+
+ protect_page(source, PAGE_ENTRY_I);
+ expect_pgm_int();
+ mvpg(0, fresh, source);
+ report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "source invalid");
+ unprotect_page(source, PAGE_ENTRY_I);
+ fresh += PAGE_SIZE;
+
+ protect_page(fresh, PAGE_ENTRY_I);
+ expect_pgm_int();
+ mvpg(0, fresh, source);
+ report(clear_pgm_int() == PGM_INT_CODE_PAGE_TRANSLATION, "destination invalid");
+ fresh += PAGE_SIZE;
+
+ report_prefix_pop();
+ report_prefix_push("cco=1");
+ /*
+ * Setting the CCO bit should suppress page translation exceptions,
+ * but not protection exceptions.
+ */
+ protect_page(fresh, PAGE_ENTRY_P);
+ expect_pgm_int();
+ mvpg(CCO, fresh, source);
+ report(clear_pgm_int() == PGM_INT_CODE_PROTECTION, "destination read only");
+ fresh += PAGE_SIZE;
+
+ protect_page(fresh, PAGE_ENTRY_I);
+ cc = mvpg(CCO, fresh, source);
+ report(cc == 1, "destination invalid");
+ fresh += PAGE_SIZE;
+
+ protect_page(source, PAGE_ENTRY_I);
+ cc = mvpg(CCO, fresh, source);
+ report(cc == 2, "source invalid");
+ fresh += PAGE_SIZE;
+
+ protect_page(fresh, PAGE_ENTRY_I);
+ cc = mvpg(CCO, fresh, source);
+ report(cc == 2, "source and destination invalid");
+ fresh += PAGE_SIZE;
+
+ unprotect_page(source, PAGE_ENTRY_I);
+ report_prefix_pop();
+ report_prefix_pop();
+}
+
+int main(void)
+{
+ report_prefix_push("mvpg");
+
+ init_page(source);
+ fresh = alloc_pages_flags(MEM_ORDER, FLAG_DONTZERO | FLAG_FRESH);
+ assert(fresh);
+
+ test_exceptions();
+ test_success();
+ test_small_loop("nommu");
+
+ setup_vm();
+
+ test_small_loop("mmu");
+ test_mmu_prot();
+
+ report_prefix_pop();
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 2298be6c..9f81a608 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -99,3 +99,7 @@ file = uv-guest.elf

[sie]
file = sie.elf
+
+[mvpg]
+file = mvpg.elf
+timeout = 10
--
2.26.2