Re: [kvm-unit-tests PATCH v8 6/6] s390x: SCLP unit test

David Hildenbrand
2020-01-22T10:22:25Z

On 22.01.20 11:10, David Hildenbrand wrote:
> On 20.01.20 19:42, Claudio Imbrenda wrote:
>> 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>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>> Acked-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>> s390x/Makefile | 1 +
>> s390x/sclp.c | 474 ++++++++++++++++++++++++++++++++++++++++++++
>> s390x/unittests.cfg | 8 +
>> 3 files changed, 483 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..215347e
>> --- /dev/null
>> +++ b/s390x/sclp.c
>> @@ -0,0 +1,474 @@
>> +/*
>> + * 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))
>> +
>> +#define LC_SIZE (2 * PAGE_SIZE)
>> +
>> +static uint8_t pagebuf[LC_SIZE] __attribute__((aligned(LC_SIZE))); /* scratch pages used for some tests */
>> +static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE))); /* temporary lowcore for test_sccb_prefix */
>> +static uint8_t sccb_template[PAGE_SIZE]; /* SCCB template to be used */
>> +static uint32_t valid_code; /* valid command code for READ SCP INFO */
>> +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);
>> + if (exp_pgm != PGM_NONE)
>> + expect_pgm_int();
>> + /* perform the actual 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 be used when the template should not be
>> + * copied and the memory address should not be touched.
>> + */
>> +static bool test_one_ro(uint32_t cmd, uint8_t *addr, uint64_t exp_pgm, uint16_t exp_rc)
>> +{
>> + return test_one_sccb(cmd, addr, 0, exp_pgm, exp_rc);
>> +}
>> +
>> +/**
>> + * 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);
>
> Doing a fresh ./configure + make on RHEL7 gives me
>
> [linux1@rhkvm01 kvm-unit-tests]$ make
> gcc -std=gnu99 -ffreestanding -I /home/linux1/git/kvm-unit-tests/lib -I /home/linux1/git/kvm-unit-tests/lib/s390x -I lib -O2 -march=zEC12 -fno-delete-null-pointer-checks -g -MMD -MF s390x/.sclp.d -Wall -Wwrite-strings -Wempty-body -Wuninitialized -Wignored-qualifiers -Werror -fomit-frame-pointer -Wno-frame-address -fno-pic -Wclobbered -Wunused-but-set-parameter -Wmissing-parameter-type -Wold-style-declaration -Woverride-init -Wmissing-prototypes -Wstrict-prototypes -c -o s390x/sclp.o s390x/sclp.c
> s390x/sclp.c: In function 'test_one_simple':
> s390x/sclp.c:121:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
> ((SCCBHeader *)sccb_template)->length = sccb_len;
> ^
> s390x/sclp.c: At top level:
> cc1: error: unrecognized command line option "-Wno-frame-address" [-Werror]
> cc1: all warnings being treated as errors
> make: *** [s390x/sclp.o] Error 1

The following makes it work:

diff --git a/s390x/sclp.c b/s390x/sclp.c
index c13fa60..0b8117a 100644
--- a/s390x/sclp.c
+++ b/s390x/sclp.c
@@ -117,8 +117,10 @@ static bool test_one_ro(uint32_t cmd, uint8_t *addr, uint64_t exp_pgm, uint16_t
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)
{
+ SCCBHeader *header = (void *)sccb_template;
+
memset(sccb_template, 0, sizeof(sccb_template));
- ((SCCBHeader *)sccb_template)->length = sccb_len;
+ header->length = sccb_len;
return test_one_sccb(cmd, addr, buf_len, exp_pgm, exp_rc);
}

--
Thanks,

David / dhildenb