Re: [PATCH v5 09/10] tools: update hmm-test to support device coherent type

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

Hi Alistair,
This is the last patch to be reviewed from this series. It already has 
the changes from
your last feedback (V3). Would you mind to take a look?
Thanks a lot for reviewing the rest!

Regards,
Alex Sierra

On 1/28/2022 2:08 PM, 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
> 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>
> Acked-by: Felix Kuehling <Felix.Kuehling@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.
> v4:
> Check for the number of pages successfully migrated from coherent
> device to system at migrate_multiple test.
> ---
>   tools/testing/selftests/vm/hmm-tests.c | 123 ++++++++++++++++++++-----
>   1 file changed, 102 insertions(+), 21 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
> index 203323967b50..84ec8c4a1dc7 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 +1184,13 @@ 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);
> +			ASSERT_EQ(ret, 0);
> +			ASSERT_EQ(buffer->cpages, npages);
> +		}
> +
>   		for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
>   			ASSERT_EQ(ptr[i], i);
>   
> @@ -1354,13 +1428,13 @@ 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);
>   
> @@ -1377,9 +1451,16 @@ 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);
>   }