Re: [PATCH i-g-t 2/2] tests/xe_exec_sip: Write on invalidinstr

["Manszewski, Christoph" <christoph.manszewski@intel.com>]

Hi Zbigniew,

On 2.10.2024 09:50, Zbigniew Kempczyński wrote:
> On Wed, Sep 25, 2024 at 03:30:03PM +0200, Christoph Manszewski wrote:
>> Currently we use 'gpgpu_shader__write_on_exception' only in a negative
>> way which causes the write not happening in the default (passing) case.
>> Change one of the usages to positive, to ensure the expected value has
>> been written.
>>
>> Signed-off-by: Christoph Manszewski <christoph.manszewski@intel.com>
>> Cc: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>
>> ---
>>   tests/intel/xe_exec_sip.c | 80 ++++++++++++++++++++++++---------------
>>   1 file changed, 49 insertions(+), 31 deletions(-)
>>
>> diff --git a/tests/intel/xe_exec_sip.c b/tests/intel/xe_exec_sip.c
>> index ed27d9c32..2294468c2 100644
>> --- a/tests/intel/xe_exec_sip.c
>> +++ b/tests/intel/xe_exec_sip.c
>> @@ -27,10 +27,12 @@
>>   #define WIDTH 64
>>   #define HEIGHT 64
>>   
>> -#define COLOR_C4 0xc4
>> +#define COLOR_C4 0xc4c4c4c4
>>   
>>   #define SHADER_CANARY 0x01010101
>> -#define SIP_CANARY 0x02020202
>> +#define SHADER_CANARY2 0x02020202
>> +#define SIP_CANARY 0x03030303
>> +#define SIP_CANARY2 0x04040404
>>   
>>   enum shader_type {
>>   	SHADER_HANG,
>> @@ -71,7 +73,7 @@ create_fill_buf(int fd, int width, int height, uint8_t color)
>>   static struct gpgpu_shader *get_shader(int fd, enum shader_type shader_type)
>>   {
>>   	static struct gpgpu_shader *shader;
>> -	uint32_t bad;
>> +	uint32_t expected_cr0_bit;
>>   
>>   	shader = gpgpu_shader_create(fd);
>>   	if (shader_type == SHADER_INV_INSTR_WALKER_ENABLED)
>> @@ -92,15 +94,17 @@ static struct gpgpu_shader *get_shader(int fd, enum shader_type shader_type)
>>   		__attribute__ ((fallthrough));
>>   	case SHADER_INV_INSTR_DISABLED:
>>   	case SHADER_INV_INSTR_WALKER_ENABLED:
>> -		bad = (shader_type == SHADER_INV_INSTR_DISABLED) ? ILLEGAL_OPCODE_ENABLE : 0;
>> -		gpgpu_shader__write_on_exception(shader, 1, 0, 0, ILLEGAL_OPCODE_ENABLE, bad);
>> +		expected_cr0_bit = shader_type == SHADER_INV_INSTR_DISABLED ?
>> +				   0 : ILLEGAL_OPCODE_ENABLE;
>> +		gpgpu_shader__write_on_exception(shader, SHADER_CANARY2, 1, 0,
>> +						 ILLEGAL_OPCODE_ENABLE, expected_cr0_bit);
>>   		gpgpu_shader__nop(shader);
>>   		gpgpu_shader__nop(shader);
>>   		/* modify second nop, set only opcode bits[6:0] */
>>   		shader->instr[gpgpu_shader_last_instr(shader)][0] = 0x7f;
>> -		/* SIP should clear exception bit */
>> -		bad = ILLEGAL_OPCODE_STATUS;
>> -		gpgpu_shader__write_on_exception(shader, 2, 0, 0, ILLEGAL_OPCODE_STATUS, bad);
>> +		/* SIP should clear exception bit, negative check */
>> +		gpgpu_shader__write_on_exception(shader, SHADER_CANARY2, 0, 0,
>> +						 ILLEGAL_OPCODE_STATUS, ILLEGAL_OPCODE_STATUS);
>>   		break;
>>   	}
>>   
>> @@ -120,7 +124,8 @@ static struct gpgpu_shader *get_sip(int fd, enum sip_type sip_type, unsigned int
>>   
>>   	switch (sip_type) {
>>   	case SIP_INV_INSTR:
>> -		gpgpu_shader__write_on_exception(sip, 1, 0, y_offset, ILLEGAL_OPCODE_STATUS, 0);
>> +		gpgpu_shader__write_on_exception(sip, SIP_CANARY2, 0, y_offset,
>> +						 ILLEGAL_OPCODE_STATUS, 0);
>>   		break;
>>   	default:
>>   		break;
>> @@ -135,7 +140,7 @@ static uint32_t gpgpu_shader(int fd, struct intel_bb *ibb, enum shader_type shad
>>   			     enum sip_type sip_type, unsigned int threads, unsigned int width,
>>   			     unsigned int height)
>>   {
>> -	struct intel_buf *buf = create_fill_buf(fd, width, height, COLOR_C4);
>> +	struct intel_buf *buf = create_fill_buf(fd, width, height, (uint8_t)COLOR_C4);
>>   	struct gpgpu_shader *sip = get_sip(fd, sip_type, height / 2);
>>   	struct gpgpu_shader *shader = get_shader(fd, shader_type);
>>   
>> @@ -148,59 +153,72 @@ static uint32_t gpgpu_shader(int fd, struct intel_bb *ibb, enum shader_type shad
>>   	return buf->handle;
>>   }
>>   
>> -static void check_fill_buf(uint8_t *ptr, const int width, const int x,
>> -			   const int y, const uint8_t color)
>> +static void check_fill_buf(uint32_t *ptr, const int dword_width, const int x, const int y,
>> +			   const uint32_t color)
>>   {
>> -	const uint8_t val = ptr[y * width + x];
>> +	const uint32_t val = ptr[y * dword_width + x];
>>   
>>   	igt_assert_f(val == color,
>> -		     "Expected 0x%02x, found 0x%02x at (%d,%d)\n",
>> +		     "Expected 0x%08x, found 0x%08x at (%d,%d)\n",
>>   		     color, val, x, y);
>>   }
>>   
>> -static void check_buf(int fd, uint32_t handle, int width, int height,
>> -		      enum shader_type shader_type, enum sip_type sip_type, uint8_t poison_c)
>> +static void check_buf(int fd, uint32_t handle, int width, int height, int thread_count_expected,
>> +		      enum shader_type shader_type, enum sip_type sip_type, uint32_t poison_c)
>>   {
>> +	int thread_count = 0, sip_count = 0, invalidinstr_count = 0;
>>   	unsigned int sz = ALIGN(width * height, 4096);
>> -	int thread_count = 0, sip_count = 0;
>> +	const uint32_t dword_width = width / 4;
>>   	uint32_t *ptr;
>>   	int i, j;
>>   
>>   	ptr = xe_bo_mmap_ext(fd, handle, sz, PROT_READ);
>>   
>> -	for (i = 0, j = 0; j < height / 2; ++j) {
>> -		if (ptr[j * width / 4] == SHADER_CANARY) {
>> +	for (i = 1, j = 0; j < height / 2; ++j) {
>> +		if (ptr[j * dword_width] == SHADER_CANARY)
>>   			++thread_count;
>> -			i = 4;
>> +		else
>> +			check_fill_buf(ptr, dword_width, 0, j, poison_c);
>> +
>> +		if (ptr[j * dword_width + 1] == SHADER_CANARY2) {
>> +			++invalidinstr_count;
>> +			++i;
>>   		}
>>   
>> -		for (; i < width; i++)
>> -			check_fill_buf((uint8_t *)ptr, width, i, j, poison_c);
>> +		for (; i < dword_width; i++)
>> +			check_fill_buf(ptr, dword_width, i, j, poison_c);
>>   
>> -		i = 0;
>> +		i = 1;
>>   	}
>>   
>>   	for (i = 0, j = height / 2; j < height; ++j) {
>> -		if (ptr[j * width / 4] == SIP_CANARY) {
>> +		if (ptr[j * dword_width] == SIP_CANARY) {
>>   			++sip_count;
>>   			i = 4;
>>   		}
>>   
>> -		for (; i < width; i++)
>> -			check_fill_buf((uint8_t *)ptr, width, i, j, poison_c);
>> +		for (; i < dword_width; i++)
>> +			check_fill_buf(ptr, dword_width, i, j, poison_c);
>>   
>>   		i = 0;
>>   	}
> 
> I thought to simplify above to avoid looping twice, especially you've
> added x position in write_on_exception(). This would require to write
> SHADER_CANARY on x == 0, SHADER_CANARY2 on x == 1, SHADER_SIP on x == 2
> and SHADER_SIP2 on x == 3. I think this would make code clearer, especially
> you wouldn't need to double the surface size. But this is not a blocker
> for this patch, especially it is doing what I asked for (proves
> write_on_exception() has the reflection in the memory).
> 
> Reviewed-by: Zbigniew Kempczyński <zbigniew.kempczynski@intel.com>

Thanks, I'll allow myself to take that r-b and leave the check buf logic 
refactor for another day =)

Thanks,
Christoph

> 
> --
> Zbigniew
> 
>>   
>>   	igt_assert(thread_count);
>> -	if (shader_type == SHADER_INV_INSTR_DISABLED)
>> -		igt_assert(!sip_count);
>> -	else if (sip_type == SIP_INV_INSTR && shader_type != SHADER_INV_INSTR_DISABLED)
>> +
>> +	if (shader_type >= SHADER_INV_INSTR_DISABLED &&
>> +	    shader_type <= SHADER_INV_INSTR_WALKER_ENABLED)
>> +		igt_assert_f(thread_count == invalidinstr_count,
>> +			     "Thread and invalid instruction count mismatch, %d != %d\n",
>> +			     thread_count, invalidinstr_count);
>> +	else
>> +		igt_assert_eq(invalidinstr_count, 0);
>> +
>> +	if (sip_type == SIP_INV_INSTR && shader_type != SHADER_INV_INSTR_DISABLED)
>>   		igt_assert_f(thread_count == sip_count,
>>   			     "Thread and SIP count mismatch, %d != %d\n",
>>   			     thread_count, sip_count);
>>   	else
>> -		igt_assert(sip_count == 0);
>> +		igt_assert_eq(sip_count, 0);
>>   
>>   	munmap(ptr, sz);
>>   }
>> @@ -270,7 +288,7 @@ static void test_sip(enum shader_type shader_type, enum sip_type sip_type,
>>   	intel_bb_sync(ibb);
>>   	igt_assert_lt_u64(igt_nsec_elapsed(&ts), timeout);
>>   
>> -	check_buf(fd, handle, width, height, shader_type, sip_type, COLOR_C4);
>> +	check_buf(fd, handle, width, height, threads, shader_type, sip_type, COLOR_C4);
>>   
>>   	gem_close(fd, handle);
>>   	intel_bb_destroy(ibb);
>> -- 
>> 2.34.1
>>