[kvm-unit-tests PATCH v4 3/3] s390x: SCLP unit test

Claudio Imbrenda
2019-11-19T09:53:52Z

SCLP unit test. Testing the following:

* Correctly ignoring instruction bits that should be ignored
* Privileged instruction check
* Check for addressing exceptions
* Specification exceptions:
- SCCB size less than 8
- SCCB unaligned
- SCCB overlaps prefix or lowcore
- SCCB address higher than 2GB
* Return codes for
- Invalid command
- SCCB too short (but at least 8)
- SCCB page boundary violation

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
s390x/Makefile | 1 +
s390x/sclp.c | 465 ++++++++++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
3 files changed, 469 insertions(+)
create mode 100644 s390x/sclp.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 3744372..ddb4b48 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -16,6 +16,7 @@ tests += $(TEST_DIR)/diag288.elf
tests += $(TEST_DIR)/stsi.elf
tests += $(TEST_DIR)/skrf.elf
tests += $(TEST_DIR)/smp.elf
+tests += $(TEST_DIR)/sclp.elf
tests_binary = $(patsubst %.elf,%.bin,$(tests))

all: directories test_cases test_cases_binary
diff --git a/s390x/sclp.c b/s390x/sclp.c
new file mode 100644
index 0000000..aeb0b04
--- /dev/null
+++ b/s390x/sclp.c
@@ -0,0 +1,465 @@
+/*
+ * Service Call tests
+ *
+ * Copyright (c) 2019 IBM Corp
+ *
+ * Authors:
+ * Claudio Imbrenda <imbrenda@linux.ibm.com>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/asm-offsets.h>
+#include <asm/interrupt.h>
+#include <sclp.h>
+
+#define PGM_NONE 1
+#define PGM_BIT_SPEC (1ULL << PGM_INT_CODE_SPECIFICATION)
+#define PGM_BIT_ADDR (1ULL << PGM_INT_CODE_ADDRESSING)
+#define PGM_BIT_PRIV (1ULL << PGM_INT_CODE_PRIVILEGED_OPERATION)
+#define MKPTR(x) ((void *)(uint64_t)(x))
+
+/* two pages of scratch memory to be used for some of the tests */
+static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
+/* used as prefix when testing prefix access, to guarantee that prefix != 0 */
+static uint8_t prefix_buf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
+/* SCCB template used to */
+static uint8_t sccb_template[PAGE_SIZE];
+/* the valid command code to use for getting SCP information */
+static uint32_t valid_code;
+/* points to lowcore (real address 0) */
+static struct lowcore *lc;
+
+/**
+ * Perform one service call, handling exceptions and interrupts.
+ */
+static int sclp_service_call_test(unsigned int command, void *sccb)
+{
+ int cc;
+
+ sclp_mark_busy();
+ sclp_setup_int();
+ cc = servc(command, __pa(sccb));
+ if (lc->pgm_int_code) {
+ sclp_handle_ext();
+ return 0;
+ }
+ if (!cc)
+ sclp_wait_busy();
+ return cc;
+}
+
+/**
+ * Perform one test at the given address, optionally using the SCCB template,
+ * checking for the expected program interrupts and return codes.
+ *
+ * The parameter buf_len indicates the number of bytes of the template that
+ * should be copied to the test address, and should be 0 when the test
+ * address is invalid, in which case nothing is copied.
+ *
+ * The template is used to simplify tests where the same buffer content is
+ * used many times in a row, at different addresses.
+ *
+ * Returns true in case of success or false in case of failure
+ */
+static bool test_one_sccb(uint32_t cmd, uint8_t *addr, uint16_t buf_len, uint64_t exp_pgm, uint16_t exp_rc)
+{
+ SCCBHeader *h = (SCCBHeader *)addr;
+ int res, pgm;
+
+ /* Copy the template to the test address if needed */
+ if (buf_len)
+ memcpy(addr, sccb_template, buf_len);
+ expect_pgm_int();
+ /* perform the actuall call */
+ res = sclp_service_call_test(cmd, h);
+ if (res) {
+ report_info("SCLP not ready (command %#x, address %p, cc %d)", cmd, addr, res);
+ return false;
+ }
+ pgm = clear_pgm_int();
+ /* Check if the program exception was one of the expected ones */
+ if (!((1ULL << pgm) & exp_pgm)) {
+ report_info("First failure at addr %p, buf_len %d, cmd %#x, pgm code %d",
+ addr, buf_len, cmd, pgm);
+ return false;
+ }
+ /* Check if the response code is the one expected */
+ if (exp_rc && exp_rc != h->response_code) {
+ report_info("First failure at addr %p, buf_len %d, cmd %#x, resp code %#x",
+ addr, buf_len, cmd, h->response_code);
+ return false;
+ }
+ return true;
+}
+
+/**
+ * Wrapper for test_one_sccb to set up a simple SCCB template.
+ *
+ * The parameter sccb_len indicates the value that will be saved in the SCCB
+ * length field of the SCCB, buf_len indicates the number of bytes of
+ * template that need to be copied to the actual test address. In many cases
+ * it's enough to clear/copy the first 8 bytes of the buffer, while the SCCB
+ * itself can be larger.
+ *
+ * Returns true in case of success or false in case of failure
+ */
+static bool test_one_simple(uint32_t cmd, uint8_t *addr, uint16_t sccb_len,
+ uint16_t buf_len, uint64_t exp_pgm, uint16_t exp_rc)
+{
+ memset(sccb_template, 0, sizeof(sccb_template));
+ ((SCCBHeader *)sccb_template)->length = sccb_len;
+ return test_one_sccb(cmd, addr, buf_len, exp_pgm, exp_rc);
+}
+
+/**
+ * Test SCCB lengths < 8.
+ */
+static void test_sccb_too_short(void)
+{
+ int len;
+
+ for (len = 0; len < 8; len++)
+ if (!test_one_simple(valid_code, pagebuf, len, 8, PGM_BIT_SPEC, 0))
+ break;
+
+ report("SCCB too short", len == 8);
+}
+
+/**
+ * Test SCCBs that are not 64-bit aligned.
+ */
+static void test_sccb_unaligned(void)
+{
+ int offset;
+
+ for (offset = 1; offset < 8; offset++)
+ if (!test_one_simple(valid_code, offset + pagebuf, 8, 8, PGM_BIT_SPEC, 0))
+ break;
+ report("SCCB unaligned", offset == 8);
+}
+
+/**
+ * Test SCCBs whose address is in the lowcore or prefix area.
+ */
+static void test_sccb_prefix(void)
+{
+ uint8_t scratch[2 * PAGE_SIZE];
+ uint32_t prefix, new_prefix;
+ int offset;
+
+ /*
+ * copy the current lowcore to the future new location, otherwise we
+ * will not have a valid lowcore after setting the new prefix.
+ */
+ memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
+ /* save the current prefix (it's probably going to be 0) */
+ asm volatile("stpx %0" : "=Q" (prefix));
+ /*
+ * save the current content of absolute pages 0 and 1, so we can
+ * restore them after we trash them later on
+ */
+ memcpy(scratch, (void *)(intptr_t)prefix, 2 * PAGE_SIZE);
+ /* set the new prefix to prefix_buf */
+ new_prefix = (uint32_t)(intptr_t)prefix_buf;
+ asm volatile("spx %0" : : "Q" (new_prefix) : "memory");
+
+ /*
+ * testing with SCCB addresses in the lowcore; since we can't
+ * actually trash the lowcore (unsurprisingly, things break if we
+ * do), this will be a read-only test.
+ */
+ for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
+ if (!test_one_sccb(valid_code, MKPTR(offset), 0, PGM_BIT_SPEC, 0))
+ break;
+ report("SCCB low pages", offset == 2 * PAGE_SIZE);
+
+ /*
+ * this will trash the contents of the two pages at absolute
+ * address 0; we will need to restore them later.
+ */
+ for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
+ if (!test_one_simple(valid_code, MKPTR(new_prefix + offset), 8, 8, PGM_BIT_SPEC, 0))
+ break;
+ report("SCCB prefix pages", offset == 2 * PAGE_SIZE);
+
+ /* restore the previous contents of absolute pages 0 and 1 */
+ memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
+ /* restore the prefix to the original value */
+ asm volatile("spx %0" : : "Q" (prefix) : "memory");
+}
+
+/**
+ * Test SCCBs that are above 2GB. If outside of memory, an addressing
+ * exception is also allowed.
+ */
+static void test_sccb_high(void)
+{
+ SCCBHeader *h = (SCCBHeader *)pagebuf;
+ uintptr_t a[33 * 4 * 2 + 2]; /* for the list of addresses to test */
+
+ uint64_t maxram;
+ int i, pgm, len = 0;
+
+ h->length = 8;
+ /* addresses with 1 bit set in the first 33 bits */
+ for (i = 0; i < 33; i++)
+ a[len++] = 1UL << (i + 31);
+ /* addresses with 2 consecutive bits set in the first 33 bits */
+ for (i = 0; i < 33; i++)
+ a[len++] = 3UL << (i + 31);
+ /* addresses with all bits set in bits 0..N */
+ for (i = 0; i < 33; i++)
+ a[len++] = 0xffffffff80000000UL << i;
+ /* addresses with all bits set in bits N..33 */
+ a[len++] = 0x80000000;
+ for (i = 1; i < 33; i++, len++)
+ a[len] = a[len - 1] | (1UL << (i + 31));
+ /* all the addresses above, but adding the offset of a valid buffer */
+ for (i = 0; i < len; i++)
+ a[len + i] = a[i] + (intptr_t)h;
+ len += i;
+ /* two more hand-crafted addresses */
+ a[len++] = 0xdeadbeef00000000;
+ a[len++] = 0xdeaddeadbeef0000;
+
+ maxram = get_ram_size();
+ for (i = 0; i < len; i++) {
+ pgm = PGM_BIT_SPEC | (a[i] >= maxram ? PGM_BIT_ADDR : 0);
+ if (!test_one_sccb(valid_code, (void *)a[i], 0, pgm, 0))
+ break;
+ }
+ report("SCCB high addresses", i == len);
+}
+
+/**
+ * Test invalid commands, both invalid command detail codes and valid
+ * ones with invalid command class code.
+ */
+static void test_inval(void)
+{
+ const uint16_t res = SCLP_RC_INVALID_SCLP_COMMAND;
+ uint32_t cmd;
+ int i;
+
+ report_prefix_push("Invalid command");
+ for (i = 0; i < 65536; i++) {
+ cmd = 0xdead0000 | i;
+ if (!test_one_simple(cmd, pagebuf, PAGE_SIZE, PAGE_SIZE, PGM_NONE, res))
+ break;
+ }
+ report("Command detail code", i == 65536);
+
+ for (i = 0; i < 256; i++) {
+ cmd = (valid_code & ~0xff) | i;
+ if (cmd == valid_code)
+ continue;
+ if (!test_one_simple(cmd, pagebuf, PAGE_SIZE, PAGE_SIZE, PGM_NONE, res))
+ break;
+ }
+ report("Command class code", i == 256);
+ report_prefix_pop();
+}
+
+
+/**
+ * Test short SCCBs (but larger than 8).
+ */
+static void test_short(void)
+{
+ const uint16_t res = SCLP_RC_INSUFFICIENT_SCCB_LENGTH;
+ int len;
+
+ for (len = 8; len < 144; len++)
+ if (!test_one_simple(valid_code, pagebuf, len, len, PGM_NONE, res))
+ break;
+ report("Insufficient SCCB length (Read SCP info)", len == 144);
+
+ for (len = 8; len < 40; len++)
+ if (!test_one_simple(SCLP_READ_CPU_INFO, pagebuf, len, len, PGM_NONE, res))
+ break;
+ report("Insufficient SCCB length (Read CPU info)", len == 40);
+}
+
+/**
+ * Test SCCB page boundary violations.
+ */
+static void test_boundary(void)
+{
+ const uint32_t cmd = SCLP_CMD_WRITE_EVENT_DATA;
+ const uint16_t res = SCLP_RC_SCCB_BOUNDARY_VIOLATION;
+ WriteEventData *sccb = (WriteEventData *)sccb_template;
+ int len, offset;
+
+ memset(sccb_template, 0, sizeof(sccb_template));
+ sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
+ for (len = 32; len <= 4096; len++) {
+ offset = len & 7 ? len & ~7 : len - 8;
+ for (offset = 4096 - offset; offset < 4096; offset += 8) {
+ sccb->h.length = len;
+ if (!test_one_sccb(cmd, offset + pagebuf, len, PGM_NONE, res))
+ goto out;
+ }
+ }
+out:
+ report("SCCB page boundary violation", len > 4096 && offset == 4096);
+}
+
+/**
+ * Test excessively long SCCBs.
+ */
+static void test_toolong(void)
+{
+ const uint32_t cmd = SCLP_CMD_WRITE_EVENT_DATA;
+ const uint16_t res = SCLP_RC_SCCB_BOUNDARY_VIOLATION;
+ WriteEventData *sccb = (WriteEventData *)sccb_template;
+ int len;
+
+ memset(sccb_template, 0, sizeof(sccb_template));
+ sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
+ for (len = 4097; len < 8192; len++) {
+ sccb->h.length = len;
+ if (!test_one_sccb(cmd, pagebuf, PAGE_SIZE, PGM_NONE, res))
+ break;
+ }
+ report("SCCB bigger than 4k", len == 8192);
+}
+
+/**
+ * Test privileged operation.
+ */
+static void test_priv(void)
+{
+ SCCBHeader *h = (SCCBHeader *)pagebuf;
+
+ report_prefix_push("Privileged operation");
+ h->length = 8;
+ expect_pgm_int();
+ enter_pstate();
+ servc(valid_code, __pa(h));
+ check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
+ report_prefix_pop();
+}
+
+/**
+ * Test addressing exceptions. We need to test SCCB addresses between the
+ * end of available memory and 2GB, because after 2GB a specification
+ * exception is also allowed.
+ * Only applicable if the VM has less than 2GB of memory
+ */
+static void test_addressing(void)
+{
+ unsigned long i, maxram = get_ram_size();
+
+ /* the VM has more than 2GB of memory */
+ if (maxram >= 0x80000000) {
+ report_skip("Invalid SCCB address");
+ return;
+ }
+ /* test all possible valid addresses immediately after the end of memory
+ * up to 64KB after the end of memory
+ */
+ for (i = 0; i < 0x10000 && i + maxram < 0x80000000; i += 8)
+ if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+ goto out;
+ /* test more addresses until we reach 1MB after end of memory;
+ * increment by a prime number (times 8) in order to test all
+ * possible valid offsets inside pages
+ */
+ for (; i < 0x100000 && i + maxram < 0x80000000 ; i += 808)
+ if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+ goto out;
+ /* test the remaining addresses until we reach address 2GB;
+ * increment by a prime number (times 8) in order to test all
+ * possible valid offsets inside pages
+ */
+ for (; i < 0x80000000; i += 800024)
+ if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+ goto out;
+out:
+ report("Invalid SCCB address", i >= 0x80000000);
+}
+
+/**
+ * Test some bits in the instruction format that are specified to be ignored.
+ */
+static void test_instbits(void)
+{
+ SCCBHeader *h = (SCCBHeader *)pagebuf;
+ int cc;
+
+ expect_pgm_int();
+ sclp_mark_busy();
+ h->length = 8;
+ sclp_setup_int();
+
+ asm volatile(
+ " .insn rre,0xb2204200,%1,%2\n" /* servc %1,%2 */
+ " ipm %0\n"
+ " srl %0,28"
+ : "=&d" (cc) : "d" (valid_code), "a" (__pa(pagebuf))
+ : "cc", "memory");
+ if (lc->pgm_int_code) {
+ sclp_handle_ext();
+ cc = 1;
+ } else if (!cc)
+ sclp_wait_busy();
+ report("Instruction format ignored bits", cc == 0);
+}
+
+/**
+ * Find a valid SCLP command code; not all codes are always allowed, and
+ * probing should be performed in the right order.
+ */
+static void find_valid_sclp_code(void)
+{
+ const unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
+ SCLP_CMDW_READ_SCP_INFO };
+ SCCBHeader *h = (SCCBHeader *)pagebuf;
+ int i, cc;
+
+ for (i = 0; i < ARRAY_SIZE(commands); i++) {
+ sclp_mark_busy();
+ memset(h, 0, sizeof(*h));
+ h->length = 4096;
+
+ valid_code = commands[i];
+ cc = sclp_service_call(commands[i], h);
+ if (cc)
+ break;
+ if (h->response_code == SCLP_RC_NORMAL_READ_COMPLETION)
+ return;
+ if (h->response_code != SCLP_RC_INVALID_SCLP_COMMAND)
+ break;
+ }
+ valid_code = 0;
+ report_abort("READ_SCP_INFO failed");
+}
+
+int main(void)
+{
+ report_prefix_push("sclp");
+ find_valid_sclp_code();
+
+ /* Test some basic things */
+ test_instbits();
+ test_priv();
+ test_addressing();
+
+ /* Test the specification exceptions */
+ test_sccb_too_short();
+ test_sccb_unaligned();
+ test_sccb_prefix();
+ test_sccb_high();
+
+ /* Test the expected response codes */
+ test_inval();
+ test_short();
+ test_boundary();
+ test_toolong();
+
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index f1b07cd..75e3d37 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -75,3 +75,6 @@ file = stsi.elf
[smp]
file = smp.elf
extra_params =-smp 2
+
+[sclp]
+file = sclp.elf
--
2.7.4