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

"Sierra Guiza, Alejandro (Alex)" <alex.sierra@xxxxxxx> · Wed, 26 Jan 2022 21:22:13 -0600

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@xxxxxxx>
---
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);
  }











