Re: [PATCH v3 09/10] tools: update hmm-test to support device coherent type

["Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>]

On 1/20/2022 12:14 AM, Alistair Popple wrote:
> On Tuesday, 11 January 2022 9:32:00 AM AEDT Alex Sierra wrote:
>> Test cases such as migrate_fault and migrate_multiple, were modified to
>> explicit migrate from device to sys memory without the need of page
>> faults, when using device coherent type.
>>
>> Snapshot test case updated to read memory device type first and based
>> on that, get the proper returned results migrate_ping_pong test case
> Where is the migrate_ping_pong test? Did you perhaps forget to add it? :-)

Migration from device coherent to system is tested with migrate_multiple 
too. Therefore,
I've removed migrate_ping_pong test. BTW, I just added the "number of 
pages migrated"
checker after migrate from coherent to system on v4 series.

Regards,
Alejandro Sierra

>
>> added to test explicit migration from device to sys memory for both
>> private and coherent zone types.
>>
>> Helpers to migrate from device to sys memory and vicerversa
>> were also added.
>>
>> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
>> ---
>> v2:
>> Set FIXTURE_VARIANT to add multiple device types to the FIXTURE. This
>> will run all the tests for each device type (private and coherent) in
>> case both existed during hmm-test driver probed.
>> ---
>>   tools/testing/selftests/vm/hmm-tests.c | 122 ++++++++++++++++++++-----
>>   1 file changed, 101 insertions(+), 21 deletions(-)
>>
>> diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
>> index 864f126ffd78..8eb81dfba4b3 100644
>> --- a/tools/testing/selftests/vm/hmm-tests.c
>> +++ b/tools/testing/selftests/vm/hmm-tests.c
>> @@ -44,6 +44,14 @@ struct hmm_buffer {
>>   	int		fd;
>>   	uint64_t	cpages;
>>   	uint64_t	faults;
>> +	int		zone_device_type;
>> +};
>> +
>> +enum {
>> +	HMM_PRIVATE_DEVICE_ONE,
>> +	HMM_PRIVATE_DEVICE_TWO,
>> +	HMM_COHERENCE_DEVICE_ONE,
>> +	HMM_COHERENCE_DEVICE_TWO,
>>   };
>>   
>>   #define TWOMEG		(1 << 21)
>> @@ -60,6 +68,21 @@ FIXTURE(hmm)
>>   	unsigned int	page_shift;
>>   };
>>   
>> +FIXTURE_VARIANT(hmm)
>> +{
>> +	int     device_number;
>> +};
>> +
>> +FIXTURE_VARIANT_ADD(hmm, hmm_device_private)
>> +{
>> +	.device_number = HMM_PRIVATE_DEVICE_ONE,
>> +};
>> +
>> +FIXTURE_VARIANT_ADD(hmm, hmm_device_coherent)
>> +{
>> +	.device_number = HMM_COHERENCE_DEVICE_ONE,
>> +};
>> +
>>   FIXTURE(hmm2)
>>   {
>>   	int		fd0;
>> @@ -68,6 +91,24 @@ FIXTURE(hmm2)
>>   	unsigned int	page_shift;
>>   };
>>   
>> +FIXTURE_VARIANT(hmm2)
>> +{
>> +	int     device_number0;
>> +	int     device_number1;
>> +};
>> +
>> +FIXTURE_VARIANT_ADD(hmm2, hmm2_device_private)
>> +{
>> +	.device_number0 = HMM_PRIVATE_DEVICE_ONE,
>> +	.device_number1 = HMM_PRIVATE_DEVICE_TWO,
>> +};
>> +
>> +FIXTURE_VARIANT_ADD(hmm2, hmm2_device_coherent)
>> +{
>> +	.device_number0 = HMM_COHERENCE_DEVICE_ONE,
>> +	.device_number1 = HMM_COHERENCE_DEVICE_TWO,
>> +};
>> +
>>   static int hmm_open(int unit)
>>   {
>>   	char pathname[HMM_PATH_MAX];
>> @@ -81,12 +122,19 @@ static int hmm_open(int unit)
>>   	return fd;
>>   }
>>   
>> +static bool hmm_is_coherent_type(int dev_num)
>> +{
>> +	return (dev_num >= HMM_COHERENCE_DEVICE_ONE);
>> +}
>> +
>>   FIXTURE_SETUP(hmm)
>>   {
>>   	self->page_size = sysconf(_SC_PAGE_SIZE);
>>   	self->page_shift = ffs(self->page_size) - 1;
>>   
>> -	self->fd = hmm_open(0);
>> +	self->fd = hmm_open(variant->device_number);
>> +	if (self->fd < 0 && hmm_is_coherent_type(variant->device_number))
>> +		SKIP(exit(0), "DEVICE_COHERENT not available");
>>   	ASSERT_GE(self->fd, 0);
>>   }
>>   
>> @@ -95,9 +143,11 @@ FIXTURE_SETUP(hmm2)
>>   	self->page_size = sysconf(_SC_PAGE_SIZE);
>>   	self->page_shift = ffs(self->page_size) - 1;
>>   
>> -	self->fd0 = hmm_open(0);
>> +	self->fd0 = hmm_open(variant->device_number0);
>> +	if (self->fd0 < 0 && hmm_is_coherent_type(variant->device_number0))
>> +		SKIP(exit(0), "DEVICE_COHERENT not available");
>>   	ASSERT_GE(self->fd0, 0);
>> -	self->fd1 = hmm_open(1);
>> +	self->fd1 = hmm_open(variant->device_number1);
>>   	ASSERT_GE(self->fd1, 0);
>>   }
>>   
>> @@ -144,6 +194,7 @@ static int hmm_dmirror_cmd(int fd,
>>   	}
>>   	buffer->cpages = cmd.cpages;
>>   	buffer->faults = cmd.faults;
>> +	buffer->zone_device_type = cmd.zone_device_type;
>>   
>>   	return 0;
>>   }
>> @@ -211,6 +262,20 @@ static void hmm_nanosleep(unsigned int n)
>>   	nanosleep(&t, NULL);
>>   }
>>   
>> +static int hmm_migrate_sys_to_dev(int fd,
>> +				   struct hmm_buffer *buffer,
>> +				   unsigned long npages)
>> +{
>> +	return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_TO_DEV, buffer, npages);
>> +}
>> +
>> +static int hmm_migrate_dev_to_sys(int fd,
>> +				   struct hmm_buffer *buffer,
>> +				   unsigned long npages)
>> +{
>> +	return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_TO_SYS, buffer, npages);
>> +}
>> +
>>   /*
>>    * Simple NULL test of device open/close.
>>    */
>> @@ -875,7 +940,7 @@ TEST_F(hmm, migrate)
>>   		ptr[i] = i;
>>   
>>   	/* Migrate memory to device. */
>> -	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
>> +	ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, npages);
>>   
>> @@ -923,7 +988,7 @@ TEST_F(hmm, migrate_fault)
>>   		ptr[i] = i;
>>   
>>   	/* Migrate memory to device. */
>> -	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
>> +	ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, npages);
>>   
>> @@ -936,7 +1001,7 @@ TEST_F(hmm, migrate_fault)
>>   		ASSERT_EQ(ptr[i], i);
>>   
>>   	/* Migrate memory to the device again. */
>> -	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
>> +	ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, npages);
>>   
>> @@ -976,7 +1041,7 @@ TEST_F(hmm, migrate_shared)
>>   	ASSERT_NE(buffer->ptr, MAP_FAILED);
>>   
>>   	/* Migrate memory to device. */
>> -	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer, npages);
>> +	ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>>   	ASSERT_EQ(ret, -ENOENT);
>>   
>>   	hmm_buffer_free(buffer);
>> @@ -1015,7 +1080,7 @@ TEST_F(hmm2, migrate_mixed)
>>   	p = buffer->ptr;
>>   
>>   	/* Migrating a protected area should be an error. */
>> -	ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, npages);
>> +	ret = hmm_migrate_sys_to_dev(self->fd1, buffer, npages);
>>   	ASSERT_EQ(ret, -EINVAL);
>>   
>>   	/* Punch a hole after the first page address. */
>> @@ -1023,7 +1088,7 @@ TEST_F(hmm2, migrate_mixed)
>>   	ASSERT_EQ(ret, 0);
>>   
>>   	/* We expect an error if the vma doesn't cover the range. */
>> -	ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 3);
>> +	ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 3);
>>   	ASSERT_EQ(ret, -EINVAL);
>>   
>>   	/* Page 2 will be a read-only zero page. */
>> @@ -1055,13 +1120,13 @@ TEST_F(hmm2, migrate_mixed)
>>   
>>   	/* Now try to migrate pages 2-5 to device 1. */
>>   	buffer->ptr = p + 2 * self->page_size;
>> -	ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 4);
>> +	ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 4);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, 4);
>>   
>>   	/* Page 5 won't be migrated to device 0 because it's on device 1. */
>>   	buffer->ptr = p + 5 * self->page_size;
>> -	ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_MIGRATE, buffer, 1);
>> +	ret = hmm_migrate_sys_to_dev(self->fd0, buffer, 1);
>>   	ASSERT_EQ(ret, -ENOENT);
>>   	buffer->ptr = p;
>>   
>> @@ -1070,8 +1135,12 @@ TEST_F(hmm2, migrate_mixed)
>>   }
>>   
>>   /*
>> - * Migrate anonymous memory to device private memory and fault it back to system
>> - * memory multiple times.
>> + * Migrate anonymous memory to device memory and back to system memory
>> + * multiple times. In case of private zone configuration, this is done
>> + * through fault pages accessed by CPU. In case of coherent zone configuration,
>> + * the pages from the device should be explicitly migrated back to system memory.
>> + * The reason is Coherent device zone has coherent access by CPU, therefore
>> + * it will not generate any page fault.
>>    */
>>   TEST_F(hmm, migrate_multiple)
>>   {
>> @@ -1107,8 +1176,7 @@ TEST_F(hmm, migrate_multiple)
>>   			ptr[i] = i;
>>   
>>   		/* Migrate memory to device. */
>> -		ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, buffer,
>> -				      npages);
>> +		ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>>   		ASSERT_EQ(ret, 0);
>>   		ASSERT_EQ(buffer->cpages, npages);
>>   
>> @@ -1116,7 +1184,12 @@ TEST_F(hmm, migrate_multiple)
>>   		for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
>>   			ASSERT_EQ(ptr[i], i);
>>   
>> -		/* Fault pages back to system memory and check them. */
>> +		/* Migrate back to system memory and check them. */
>> +		if (hmm_is_coherent_type(variant->device_number)) {
>> +			ret = hmm_migrate_dev_to_sys(self->fd, buffer, npages);
> So I think this will still pass even if nothing migrates so as mentioned on
> the previous patch I think we need to check for the number of pages that
> actually migrated. Alternatively I suppose you could do a snapshot and check
> that, but that seems like it would be harder. Otherwise I think this looks
> good.
>
>> +			ASSERT_EQ(ret, 0);
>> +		}
>> +
>>   		for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
>>   			ASSERT_EQ(ptr[i], i);
>>   
>> @@ -1312,13 +1385,13 @@ TEST_F(hmm2, snapshot)
>>   
>>   	/* Page 5 will be migrated to device 0. */
>>   	buffer->ptr = p + 5 * self->page_size;
>> -	ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_MIGRATE, buffer, 1);
>> +	ret = hmm_migrate_sys_to_dev(self->fd0, buffer, 1);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, 1);
>>   
>>   	/* Page 6 will be migrated to device 1. */
>>   	buffer->ptr = p + 6 * self->page_size;
>> -	ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 1);
>> +	ret = hmm_migrate_sys_to_dev(self->fd1, buffer, 1);
>>   	ASSERT_EQ(ret, 0);
>>   	ASSERT_EQ(buffer->cpages, 1);
>>   
>> @@ -1335,9 +1408,16 @@ TEST_F(hmm2, snapshot)
>>   	ASSERT_EQ(m[2], HMM_DMIRROR_PROT_ZERO | HMM_DMIRROR_PROT_READ);
>>   	ASSERT_EQ(m[3], HMM_DMIRROR_PROT_READ);
>>   	ASSERT_EQ(m[4], HMM_DMIRROR_PROT_WRITE);
>> -	ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL |
>> -			HMM_DMIRROR_PROT_WRITE);
>> -	ASSERT_EQ(m[6], HMM_DMIRROR_PROT_NONE);
>> +	if (!hmm_is_coherent_type(variant->device_number0)) {
>> +		ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL |
>> +				HMM_DMIRROR_PROT_WRITE);
>> +		ASSERT_EQ(m[6], HMM_DMIRROR_PROT_NONE);
>> +	} else {
>> +		ASSERT_EQ(m[5], HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL |
>> +				HMM_DMIRROR_PROT_WRITE);
>> +		ASSERT_EQ(m[6], HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE |
>> +				HMM_DMIRROR_PROT_WRITE);
>> +	}
>>   
>>   	hmm_buffer_free(buffer);
>>   }
>>
>
>
>