[PATCH v5 00/10] Add MEMORY_DEVICE_COHERENT for coherent device memory mapping

[PATCH v5 00/10] Add MEMORY_DEVICE_COHERENT for coherent device memory mapping

[Alex Sierra]

This patch series introduces MEMORY_DEVICE_COHERENT, a type of memory
owned by a device that can be mapped into CPU page tables like
MEMORY_DEVICE_GENERIC and can also be migrated like
MEMORY_DEVICE_PRIVATE.

Christoph, the suggestion to incorporate Ralph Campbell’s refcount
cleanup patch into our hardware page migration patchset originally came
from you, but it proved impractical to do things in that order because
the refcount cleanup introduced a bug with wide ranging structural
implications. Instead, we amended Ralph’s patch so that it could be
applied after merging the migration work. As we saw from the recent
discussion, merging the refcount work is going to take some time and
cooperation between multiple development groups, while the migration
work is ready now and is needed now. So we propose to merge this
patchset first and continue to work with Ralph and others to merge the
refcount cleanup separately, when it is ready.

This patch series is mostly self-contained except for a few places where
it needs to update other subsystems to handle the new memory type.

System stability and performance are not affected according to our
ongoing testing, including xfstests.

How it works: The system BIOS advertises the GPU device memory
(aka VRAM) as SPM (special purpose memory) in the UEFI system address
map.

The amdgpu driver registers the memory with devmap as
MEMORY_DEVICE_COHERENT using devm_memremap_pages. The initial user for
this hardware page migration capability is the Frontier supercomputer
project. This functionality is not AMD-specific. We expect other GPU
vendors to find this functionality useful, and possibly other hardware
types in the future.

Our test nodes in the lab are similar to the Frontier configuration,
with .5 TB of system memory plus 256 GB of device memory split across
4 GPUs, all in a single coherent address space. Page migration is
expected to improve application efficiency significantly. We will
report empirical results as they become available.

We extended hmm_test to cover migration of MEMORY_DEVICE_COHERENT. This
patch set builds on HMM and our SVM memory manager already merged in
5.15.

v2:
- test_hmm is now able to create private and coherent device mirror
instances in the same driver probe. This adds more usability to the hmm
test by not having to remove the kernel module for each device type
test (private/coherent type). This is done by passing the module
parameters spm_addr_dev0 & spm_addr_dev1. In this case, it will create
four instances of device_mirror. The first two correspond to private
device type, the last two to coherent type. Then, they can be easily
accessed from user space through /dev/hmm_mirror<num_device>. Usually
num_device 0 and 1 are for private, and 2 and 3 for coherent types.

- Coherent device type pages at gup are now migrated back to system
memory if they have been long term pinned (FOLL_LONGTERM). The reason
is these pages could eventually interfere with their own device memory
manager. A new hmm_gup_test has been added to the hmm-test to test this
functionality. It makes use of the gup_test module to long term pin
user pages that have been migrate to device memory first.

- Other patch corrections made by Felix, Alistair and Christoph.

v3:
- Based on last v2 feedback we got from Alistair, we've decided to
remove migration logic for FOLL_LONGTERM coherent device type pages at
gup for now. Ideally, this should be done through the kernel mm,
instead of calling the device driver to do it. Currently, there's no
support for migrating device pages based on pfn, mainly because
migrate_pages() relies on pages being LRU pages. Alistair mentioned, he
has started to work on adding this migrate device pages logic. For now,
we fail on get_user_pages call with FOLL_LONGTERM for DEVICE_COHERENT
pages.

- Also, hmm_gup_test has been removed from hmm-test. We plan to include
it again after this migration work is ready.

- Addressed Liam Howlett's feedback changes.

v4:
- Addressed Alistair Popple's last v3 feedback.

- Use the same system entry path for coherent device pages at
migrate_vma_insert_page.

- Add coherent device type support for try_to_migrate /
try_to_migrate_one.

- Include number of coherent device pages successfully migrated back to
system at test_hmm. Made the proper changes to hmm-test to read/check
this number.

v5:
- Rebase on 5.17-rc1.
- Addressed Alistair Popple's last v4 feedback.

Alex Sierra (10):
  mm: add zone device coherent type memory support
  mm: add device coherent vma selection for memory migration
  mm/gup: fail get_user_pages for LONGTERM dev coherent type
  drm/amdkfd: add SPM support for SVM
  drm/amdkfd: coherent type as sys mem on migration to ram
  lib: test_hmm add ioctl to get zone device type
  lib: test_hmm add module param for zone device type
  lib: add support for device coherent type in test_hmm
  tools: update hmm-test to support device coherent type
  tools: update test_hmm script to support SP config

 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |  34 ++-
 include/linux/memremap.h                 |   8 +
 include/linux/migrate.h                  |   1 +
 include/linux/mm.h                       |  16 +
 lib/test_hmm.c                           | 356 +++++++++++++++++------
 lib/test_hmm_uapi.h                      |  22 +-
 mm/gup.c                                 |   7 +
 mm/memcontrol.c                          |   6 +-
 mm/memory-failure.c                      |   8 +-
 mm/memremap.c                            |  14 +-
 mm/migrate.c                             |  55 ++--
 mm/rmap.c                                |   5 +-
 tools/testing/selftests/vm/hmm-tests.c   | 123 ++++++--
 tools/testing/selftests/vm/test_hmm.sh   |  24 +-
 14 files changed, 519 insertions(+), 160 deletions(-)

-- 
2.32.0

[PATCH v5 00/10] Add MEMORY_DEVICE_COHERENT for coherent device memory mapping

[Alex Sierra]

This patch series introduces MEMORY_DEVICE_COHERENT, a type of memory
owned by a device that can be mapped into CPU page tables like
MEMORY_DEVICE_GENERIC and can also be migrated like
MEMORY_DEVICE_PRIVATE.

Christoph, the suggestion to incorporate Ralph Campbell’s refcount
cleanup patch into our hardware page migration patchset originally came
from you, but it proved impractical to do things in that order because
the refcount cleanup introduced a bug with wide ranging structural
implications. Instead, we amended Ralph’s patch so that it could be
applied after merging the migration work. As we saw from the recent
discussion, merging the refcount work is going to take some time and
cooperation between multiple development groups, while the migration
work is ready now and is needed now. So we propose to merge this
patchset first and continue to work with Ralph and others to merge the
refcount cleanup separately, when it is ready.

This patch series is mostly self-contained except for a few places where
it needs to update other subsystems to handle the new memory type.

System stability and performance are not affected according to our
ongoing testing, including xfstests.

How it works: The system BIOS advertises the GPU device memory
(aka VRAM) as SPM (special purpose memory) in the UEFI system address
map.

The amdgpu driver registers the memory with devmap as
MEMORY_DEVICE_COHERENT using devm_memremap_pages. The initial user for
this hardware page migration capability is the Frontier supercomputer
project. This functionality is not AMD-specific. We expect other GPU
vendors to find this functionality useful, and possibly other hardware
types in the future.

Our test nodes in the lab are similar to the Frontier configuration,
with .5 TB of system memory plus 256 GB of device memory split across
4 GPUs, all in a single coherent address space. Page migration is
expected to improve application efficiency significantly. We will
report empirical results as they become available.

We extended hmm_test to cover migration of MEMORY_DEVICE_COHERENT. This
patch set builds on HMM and our SVM memory manager already merged in
5.15.

v2:
- test_hmm is now able to create private and coherent device mirror
instances in the same driver probe. This adds more usability to the hmm
test by not having to remove the kernel module for each device type
test (private/coherent type). This is done by passing the module
parameters spm_addr_dev0 & spm_addr_dev1. In this case, it will create
four instances of device_mirror. The first two correspond to private
device type, the last two to coherent type. Then, they can be easily
accessed from user space through /dev/hmm_mirror<num_device>. Usually
num_device 0 and 1 are for private, and 2 and 3 for coherent types.

- Coherent device type pages at gup are now migrated back to system
memory if they have been long term pinned (FOLL_LONGTERM). The reason
is these pages could eventually interfere with their own device memory
manager. A new hmm_gup_test has been added to the hmm-test to test this
functionality. It makes use of the gup_test module to long term pin
user pages that have been migrate to device memory first.

- Other patch corrections made by Felix, Alistair and Christoph.

v3:
- Based on last v2 feedback we got from Alistair, we've decided to
remove migration logic for FOLL_LONGTERM coherent device type pages at
gup for now. Ideally, this should be done through the kernel mm,
instead of calling the device driver to do it. Currently, there's no
support for migrating device pages based on pfn, mainly because
migrate_pages() relies on pages being LRU pages. Alistair mentioned, he
has started to work on adding this migrate device pages logic. For now,
we fail on get_user_pages call with FOLL_LONGTERM for DEVICE_COHERENT
pages.

- Also, hmm_gup_test has been removed from hmm-test. We plan to include
it again after this migration work is ready.

- Addressed Liam Howlett's feedback changes.

v4:
- Addressed Alistair Popple's last v3 feedback.

- Use the same system entry path for coherent device pages at
migrate_vma_insert_page.

- Add coherent device type support for try_to_migrate /
try_to_migrate_one.

- Include number of coherent device pages successfully migrated back to
system at test_hmm. Made the proper changes to hmm-test to read/check
this number.

v5:
- Rebase on 5.17-rc1.
- Addressed Alistair Popple's last v4 feedback.

Alex Sierra (10):
  mm: add zone device coherent type memory support
  mm: add device coherent vma selection for memory migration
  mm/gup: fail get_user_pages for LONGTERM dev coherent type
  drm/amdkfd: add SPM support for SVM
  drm/amdkfd: coherent type as sys mem on migration to ram
  lib: test_hmm add ioctl to get zone device type
  lib: test_hmm add module param for zone device type
  lib: add support for device coherent type in test_hmm
  tools: update hmm-test to support device coherent type
  tools: update test_hmm script to support SP config

 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |  34 ++-
 include/linux/memremap.h                 |   8 +
 include/linux/migrate.h                  |   1 +
 include/linux/mm.h                       |  16 +
 lib/test_hmm.c                           | 356 +++++++++++++++++------
 lib/test_hmm_uapi.h                      |  22 +-
 mm/gup.c                                 |   7 +
 mm/memcontrol.c                          |   6 +-
 mm/memory-failure.c                      |   8 +-
 mm/memremap.c                            |  14 +-
 mm/migrate.c                             |  55 ++--
 mm/rmap.c                                |   5 +-
 tools/testing/selftests/vm/hmm-tests.c   | 123 ++++++--
 tools/testing/selftests/vm/test_hmm.sh   |  24 +-
 14 files changed, 519 insertions(+), 160 deletions(-)

-- 
2.32.0

[PATCH v5 01/10] mm: add zone device coherent type memory support

[Alex Sierra]

Device memory that is cache coherent from device and CPU point of view.
This is used on platforms that have an advanced system bus (like CAPI
or CXL). Any page of a process can be migrated to such memory. However,
no one should be allowed to pin such memory so that it can always be
evicted.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v4:
- use the same system entry path for coherent device pages at
migrate_vma_insert_page.

- Add coherent device type support for try_to_migrate /
try_to_migrate_one.
---
 include/linux/memremap.h |  8 +++++++
 include/linux/mm.h       | 16 ++++++++++++++
 mm/memcontrol.c          |  6 +++---
 mm/memory-failure.c      |  8 +++++--
 mm/memremap.c            | 14 ++++++++++++-
 mm/migrate.c             | 45 ++++++++++++++++++++--------------------
 mm/rmap.c                |  5 +++--
 7 files changed, 71 insertions(+), 31 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1fafcc38acba..727b8c789193 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -39,6 +39,13 @@ struct vmem_altmap {
  * A more complete discussion of unaddressable memory may be found in
  * include/linux/hmm.h and Documentation/vm/hmm.rst.
  *
+ * MEMORY_DEVICE_COHERENT:
+ * Device memory that is cache coherent from device and CPU point of view. This
+ * is used on platforms that have an advanced system bus (like CAPI or CXL). A
+ * driver can hotplug the device memory using ZONE_DEVICE and with that memory
+ * type. Any page of a process can be migrated to such memory. However no one
+ * should be allowed to pin such memory so that it can always be evicted.
+ *
  * MEMORY_DEVICE_FS_DAX:
  * Host memory that has similar access semantics as System RAM i.e. DMA
  * coherent and supports page pinning. In support of coordinating page
@@ -59,6 +66,7 @@ struct vmem_altmap {
 enum memory_type {
 	/* 0 is reserved to catch uninitialized type fields */
 	MEMORY_DEVICE_PRIVATE = 1,
+	MEMORY_DEVICE_COHERENT,
 	MEMORY_DEVICE_FS_DAX,
 	MEMORY_DEVICE_GENERIC,
 	MEMORY_DEVICE_PCI_P2PDMA,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e1a84b1e6787..0c61bf40edef 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1106,6 +1106,7 @@ static inline bool page_is_devmap_managed(struct page *page)
 		return false;
 	switch (page->pgmap->type) {
 	case MEMORY_DEVICE_PRIVATE:
+	case MEMORY_DEVICE_COHERENT:
 	case MEMORY_DEVICE_FS_DAX:
 		return true;
 	default:
@@ -1135,6 +1136,21 @@ static inline bool is_device_private_page(const struct page *page)
 		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
+static inline bool is_device_coherent_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_COHERENT;
+}
+
+static inline bool is_dev_private_or_coherent_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		is_zone_device_page(page) &&
+		(page->pgmap->type == MEMORY_DEVICE_PRIVATE ||
+		page->pgmap->type == MEMORY_DEVICE_COHERENT);
+}
+
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
 	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 09d342c7cbd0..0882b5b2a857 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5691,8 +5691,8 @@ static int mem_cgroup_move_account(struct page *page,
  *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
  *     target for charge migration. if @target is not NULL, the entry is stored
  *     in target->ent.
- *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PRIVATE
- *     (so ZONE_DEVICE page and thus not on the lru).
+ *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is device memory and
+ *   thus not on the lru.
  *     For now we such page is charge like a regular page would be as for all
  *     intent and purposes it is just special memory taking the place of a
  *     regular page.
@@ -5726,7 +5726,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
 		 */
 		if (page_memcg(page) == mc.from) {
 			ret = MC_TARGET_PAGE;
-			if (is_device_private_page(page))
+			if (is_dev_private_or_coherent_page(page))
 				ret = MC_TARGET_DEVICE;
 			if (target)
 				target->page = page;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 14ae5c18e776..e83740f7f05e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1611,12 +1611,16 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		goto unlock;
 	}
 
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+	switch (pgmap->type) {
+	case MEMORY_DEVICE_PRIVATE:
+	case MEMORY_DEVICE_COHERENT:
 		/*
-		 * TODO: Handle HMM pages which may need coordination
+		 * TODO: Handle device pages which may need coordination
 		 * with device-side memory.
 		 */
 		goto unlock;
+	default:
+		break;
 	}
 
 	/*
diff --git a/mm/memremap.c b/mm/memremap.c
index 6aa5f0c2d11f..354c8027823f 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -44,6 +44,7 @@ EXPORT_SYMBOL(devmap_managed_key);
 static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_COHERENT ||
 	    pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_dec(&devmap_managed_key);
 }
@@ -51,6 +52,7 @@ static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_COHERENT ||
 	    pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_inc(&devmap_managed_key);
 }
@@ -327,6 +329,16 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 			return ERR_PTR(-EINVAL);
 		}
 		break;
+	case MEMORY_DEVICE_COHERENT:
+		if (!pgmap->ops->page_free) {
+			WARN(1, "Missing page_free method\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->owner) {
+			WARN(1, "Missing owner\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
 	case MEMORY_DEVICE_FS_DAX:
 		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
 		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
@@ -469,7 +481,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
 void free_devmap_managed_page(struct page *page)
 {
 	/* notify page idle for dax */
-	if (!is_device_private_page(page)) {
+	if (!is_dev_private_or_coherent_page(page)) {
 		wake_up_var(&page->_refcount);
 		return;
 	}
diff --git a/mm/migrate.c b/mm/migrate.c
index c7da064b4781..cd137aedcfe5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -345,7 +345,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
 	 * Device private pages have an extra refcount as they are
 	 * ZONE_DEVICE pages.
 	 */
-	expected_count += is_device_private_page(page);
+	expected_count += is_dev_private_or_coherent_page(page);
 	if (mapping)
 		expected_count += compound_nr(page) + page_has_private(page);
 
@@ -2611,7 +2611,7 @@ EXPORT_SYMBOL(migrate_vma_setup);
  *     handle_pte_fault()
  *       do_anonymous_page()
  * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
- * private page.
+ * private or coherent page.
  */
 static void migrate_vma_insert_page(struct migrate_vma *migrate,
 				    unsigned long addr,
@@ -2676,25 +2676,24 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
 	 */
 	__SetPageUptodate(page);
 
-	if (is_zone_device_page(page)) {
-		if (is_device_private_page(page)) {
-			swp_entry_t swp_entry;
+	if (is_device_private_page(page)) {
+		swp_entry_t swp_entry;
 
-			if (vma->vm_flags & VM_WRITE)
-				swp_entry = make_writable_device_private_entry(
-							page_to_pfn(page));
-			else
-				swp_entry = make_readable_device_private_entry(
-							page_to_pfn(page));
-			entry = swp_entry_to_pte(swp_entry);
-		} else {
-			/*
-			 * For now we only support migrating to un-addressable
-			 * device memory.
-			 */
-			pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
-			goto abort;
-		}
+		if (vma->vm_flags & VM_WRITE)
+			swp_entry = make_writable_device_private_entry(
+						page_to_pfn(page));
+		else
+			swp_entry = make_readable_device_private_entry(
+						page_to_pfn(page));
+		entry = swp_entry_to_pte(swp_entry);
+	} else if (is_zone_device_page(page) &&
+		   !is_device_coherent_page(page)) {
+		/*
+		 * We support migrating to private and coherent types
+		 * for device zone memory.
+		 */
+		pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
+		goto abort;
 	} else {
 		entry = mk_pte(page, vma->vm_page_prot);
 		if (vma->vm_flags & VM_WRITE)
@@ -2796,10 +2795,10 @@ void migrate_vma_pages(struct migrate_vma *migrate)
 		mapping = page_mapping(page);
 
 		if (is_zone_device_page(newpage)) {
-			if (is_device_private_page(newpage)) {
+			if (is_dev_private_or_coherent_page(newpage)) {
 				/*
-				 * For now only support private anonymous when
-				 * migrating to un-addressable device memory.
+				 * For now only support private and coherent
+				 * anonymous when migrating to device memory.
 				 */
 				if (mapping) {
 					migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
diff --git a/mm/rmap.c b/mm/rmap.c
index 6a1e8c7f6213..f2bd5a3da72c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1835,7 +1835,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
 		/* Update high watermark before we lower rss */
 		update_hiwater_rss(mm);
 
-		if (is_zone_device_page(page)) {
+		if (is_device_private_page(page)) {
 			unsigned long pfn = page_to_pfn(page);
 			swp_entry_t entry;
 			pte_t swp_pte;
@@ -1976,7 +1976,8 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
 					TTU_SYNC)))
 		return;
 
-	if (is_zone_device_page(page) && !is_device_private_page(page))
+	if (is_zone_device_page(page) &&
+	    !is_dev_private_or_coherent_page(page))
 		return;
 
 	/*
-- 
2.32.0

[PATCH v5 01/10] mm: add zone device coherent type memory support

[Alex Sierra]

Device memory that is cache coherent from device and CPU point of view.
This is used on platforms that have an advanced system bus (like CAPI
or CXL). Any page of a process can be migrated to such memory. However,
no one should be allowed to pin such memory so that it can always be
evicted.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v4:
- use the same system entry path for coherent device pages at
migrate_vma_insert_page.

- Add coherent device type support for try_to_migrate /
try_to_migrate_one.
---
 include/linux/memremap.h |  8 +++++++
 include/linux/mm.h       | 16 ++++++++++++++
 mm/memcontrol.c          |  6 +++---
 mm/memory-failure.c      |  8 +++++--
 mm/memremap.c            | 14 ++++++++++++-
 mm/migrate.c             | 45 ++++++++++++++++++++--------------------
 mm/rmap.c                |  5 +++--
 7 files changed, 71 insertions(+), 31 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1fafcc38acba..727b8c789193 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -39,6 +39,13 @@ struct vmem_altmap {
  * A more complete discussion of unaddressable memory may be found in
  * include/linux/hmm.h and Documentation/vm/hmm.rst.
  *
+ * MEMORY_DEVICE_COHERENT:
+ * Device memory that is cache coherent from device and CPU point of view. This
+ * is used on platforms that have an advanced system bus (like CAPI or CXL). A
+ * driver can hotplug the device memory using ZONE_DEVICE and with that memory
+ * type. Any page of a process can be migrated to such memory. However no one
+ * should be allowed to pin such memory so that it can always be evicted.
+ *
  * MEMORY_DEVICE_FS_DAX:
  * Host memory that has similar access semantics as System RAM i.e. DMA
  * coherent and supports page pinning. In support of coordinating page
@@ -59,6 +66,7 @@ struct vmem_altmap {
 enum memory_type {
 	/* 0 is reserved to catch uninitialized type fields */
 	MEMORY_DEVICE_PRIVATE = 1,
+	MEMORY_DEVICE_COHERENT,
 	MEMORY_DEVICE_FS_DAX,
 	MEMORY_DEVICE_GENERIC,
 	MEMORY_DEVICE_PCI_P2PDMA,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e1a84b1e6787..0c61bf40edef 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1106,6 +1106,7 @@ static inline bool page_is_devmap_managed(struct page *page)
 		return false;
 	switch (page->pgmap->type) {
 	case MEMORY_DEVICE_PRIVATE:
+	case MEMORY_DEVICE_COHERENT:
 	case MEMORY_DEVICE_FS_DAX:
 		return true;
 	default:
@@ -1135,6 +1136,21 @@ static inline bool is_device_private_page(const struct page *page)
 		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
+static inline bool is_device_coherent_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_COHERENT;
+}
+
+static inline bool is_dev_private_or_coherent_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		is_zone_device_page(page) &&
+		(page->pgmap->type == MEMORY_DEVICE_PRIVATE ||
+		page->pgmap->type == MEMORY_DEVICE_COHERENT);
+}
+
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
 	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 09d342c7cbd0..0882b5b2a857 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5691,8 +5691,8 @@ static int mem_cgroup_move_account(struct page *page,
  *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
  *     target for charge migration. if @target is not NULL, the entry is stored
  *     in target->ent.
- *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PRIVATE
- *     (so ZONE_DEVICE page and thus not on the lru).
+ *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is device memory and
+ *   thus not on the lru.
  *     For now we such page is charge like a regular page would be as for all
  *     intent and purposes it is just special memory taking the place of a
  *     regular page.
@@ -5726,7 +5726,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
 		 */
 		if (page_memcg(page) == mc.from) {
 			ret = MC_TARGET_PAGE;
-			if (is_device_private_page(page))
+			if (is_dev_private_or_coherent_page(page))
 				ret = MC_TARGET_DEVICE;
 			if (target)
 				target->page = page;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 14ae5c18e776..e83740f7f05e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1611,12 +1611,16 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		goto unlock;
 	}
 
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+	switch (pgmap->type) {
+	case MEMORY_DEVICE_PRIVATE:
+	case MEMORY_DEVICE_COHERENT:
 		/*
-		 * TODO: Handle HMM pages which may need coordination
+		 * TODO: Handle device pages which may need coordination
 		 * with device-side memory.
 		 */
 		goto unlock;
+	default:
+		break;
 	}
 
 	/*
diff --git a/mm/memremap.c b/mm/memremap.c
index 6aa5f0c2d11f..354c8027823f 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -44,6 +44,7 @@ EXPORT_SYMBOL(devmap_managed_key);
 static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_COHERENT ||
 	    pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_dec(&devmap_managed_key);
 }
@@ -51,6 +52,7 @@ static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
+	    pgmap->type == MEMORY_DEVICE_COHERENT ||
 	    pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_inc(&devmap_managed_key);
 }
@@ -327,6 +329,16 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 			return ERR_PTR(-EINVAL);
 		}
 		break;
+	case MEMORY_DEVICE_COHERENT:
+		if (!pgmap->ops->page_free) {
+			WARN(1, "Missing page_free method\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->owner) {
+			WARN(1, "Missing owner\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
 	case MEMORY_DEVICE_FS_DAX:
 		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
 		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
@@ -469,7 +481,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
 void free_devmap_managed_page(struct page *page)
 {
 	/* notify page idle for dax */
-	if (!is_device_private_page(page)) {
+	if (!is_dev_private_or_coherent_page(page)) {
 		wake_up_var(&page->_refcount);
 		return;
 	}
diff --git a/mm/migrate.c b/mm/migrate.c
index c7da064b4781..cd137aedcfe5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -345,7 +345,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
 	 * Device private pages have an extra refcount as they are
 	 * ZONE_DEVICE pages.
 	 */
-	expected_count += is_device_private_page(page);
+	expected_count += is_dev_private_or_coherent_page(page);
 	if (mapping)
 		expected_count += compound_nr(page) + page_has_private(page);
 
@@ -2611,7 +2611,7 @@ EXPORT_SYMBOL(migrate_vma_setup);
  *     handle_pte_fault()
  *       do_anonymous_page()
  * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
- * private page.
+ * private or coherent page.
  */
 static void migrate_vma_insert_page(struct migrate_vma *migrate,
 				    unsigned long addr,
@@ -2676,25 +2676,24 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
 	 */
 	__SetPageUptodate(page);
 
-	if (is_zone_device_page(page)) {
-		if (is_device_private_page(page)) {
-			swp_entry_t swp_entry;
+	if (is_device_private_page(page)) {
+		swp_entry_t swp_entry;
 
-			if (vma->vm_flags & VM_WRITE)
-				swp_entry = make_writable_device_private_entry(
-							page_to_pfn(page));
-			else
-				swp_entry = make_readable_device_private_entry(
-							page_to_pfn(page));
-			entry = swp_entry_to_pte(swp_entry);
-		} else {
-			/*
-			 * For now we only support migrating to un-addressable
-			 * device memory.
-			 */
-			pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
-			goto abort;
-		}
+		if (vma->vm_flags & VM_WRITE)
+			swp_entry = make_writable_device_private_entry(
+						page_to_pfn(page));
+		else
+			swp_entry = make_readable_device_private_entry(
+						page_to_pfn(page));
+		entry = swp_entry_to_pte(swp_entry);
+	} else if (is_zone_device_page(page) &&
+		   !is_device_coherent_page(page)) {
+		/*
+		 * We support migrating to private and coherent types
+		 * for device zone memory.
+		 */
+		pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
+		goto abort;
 	} else {
 		entry = mk_pte(page, vma->vm_page_prot);
 		if (vma->vm_flags & VM_WRITE)
@@ -2796,10 +2795,10 @@ void migrate_vma_pages(struct migrate_vma *migrate)
 		mapping = page_mapping(page);
 
 		if (is_zone_device_page(newpage)) {
-			if (is_device_private_page(newpage)) {
+			if (is_dev_private_or_coherent_page(newpage)) {
 				/*
-				 * For now only support private anonymous when
-				 * migrating to un-addressable device memory.
+				 * For now only support private and coherent
+				 * anonymous when migrating to device memory.
 				 */
 				if (mapping) {
 					migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
diff --git a/mm/rmap.c b/mm/rmap.c
index 6a1e8c7f6213..f2bd5a3da72c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1835,7 +1835,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
 		/* Update high watermark before we lower rss */
 		update_hiwater_rss(mm);
 
-		if (is_zone_device_page(page)) {
+		if (is_device_private_page(page)) {
 			unsigned long pfn = page_to_pfn(page);
 			swp_entry_t entry;
 			pte_t swp_pte;
@@ -1976,7 +1976,8 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
 					TTU_SYNC)))
 		return;
 
-	if (is_zone_device_page(page) && !is_device_private_page(page))
+	if (is_zone_device_page(page) &&
+	    !is_dev_private_or_coherent_page(page))
 		return;
 
 	/*
-- 
2.32.0

[PATCH v5 02/10] mm: add device coherent vma selection for memory migration

[Alex Sierra]

This case is used to migrate pages from device memory, back to system
memory. Device coherent type memory is cache coherent from device and CPU
point of view.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v2:
condition added when migrations from device coherent pages.
---
 include/linux/migrate.h |  1 +
 mm/migrate.c            | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index db96e10eb8da..66a34eae8cb6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
 enum migrate_vma_direction {
 	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
 };
 
 struct migrate_vma {
diff --git a/mm/migrate.c b/mm/migrate.c
index cd137aedcfe5..d3cc3589e1e8 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2264,7 +2264,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (is_writable_device_private_entry(entry))
 				mpfn |= MIGRATE_PFN_WRITE;
 		} else {
-			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT))
 				goto next;
 			pfn = pte_pfn(pte);
 			if (is_zero_pfn(pfn)) {
@@ -2273,6 +2274,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 				goto next;
 			}
 			page = vm_normal_page(migrate->vma, addr, pte);
+			if (page && !is_zone_device_page(page) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+				goto next;
+			if (page && is_device_coherent_page(page) &&
+			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
+			     page->pgmap->owner != migrate->pgmap_owner))
+				goto next;
 			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
 			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
 		}
-- 
2.32.0

[PATCH v5 02/10] mm: add device coherent vma selection for memory migration

[Alex Sierra]

This case is used to migrate pages from device memory, back to system
memory. Device coherent type memory is cache coherent from device and CPU
point of view.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v2:
condition added when migrations from device coherent pages.
---
 include/linux/migrate.h |  1 +
 mm/migrate.c            | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index db96e10eb8da..66a34eae8cb6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
 enum migrate_vma_direction {
 	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
 };
 
 struct migrate_vma {
diff --git a/mm/migrate.c b/mm/migrate.c
index cd137aedcfe5..d3cc3589e1e8 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2264,7 +2264,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (is_writable_device_private_entry(entry))
 				mpfn |= MIGRATE_PFN_WRITE;
 		} else {
-			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT))
 				goto next;
 			pfn = pte_pfn(pte);
 			if (is_zero_pfn(pfn)) {
@@ -2273,6 +2274,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 				goto next;
 			}
 			page = vm_normal_page(migrate->vma, addr, pte);
+			if (page && !is_zone_device_page(page) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+				goto next;
+			if (page && is_device_coherent_page(page) &&
+			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
+			     page->pgmap->owner != migrate->pgmap_owner))
+				goto next;
 			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
 			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
 		}
-- 
2.32.0

[PATCH v5 03/10] mm/gup: fail get_user_pages for LONGTERM dev coherent type

[Alex Sierra]

Avoid long term pinning for Coherent device type pages. This could
interfere with their own device memory manager. For now, we are just
returning error for PIN_LONGTERM Coherent device type pages. Eventually,
these type of pages will get migrated to system memory, once the device
migration pages support is added.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 mm/gup.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index f0af462ac1e2..f596b932d7d7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1864,6 +1864,12 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 		 * If we get a movable page, since we are going to be pinning
 		 * these entries, try to move them out if possible.
 		 */
+		if (is_dev_private_or_coherent_page(head)) {
+			WARN_ON_ONCE(is_device_private_page(head));
+			ret = -EFAULT;
+			goto unpin_pages;
+		}
+
 		if (!is_pinnable_page(head)) {
 			if (PageHuge(head)) {
 				if (!isolate_huge_page(head, &movable_page_list))
@@ -1894,6 +1900,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 	if (list_empty(&movable_page_list) && !isolation_error_count)
 		return nr_pages;
 
+unpin_pages:
 	if (gup_flags & FOLL_PIN) {
 		unpin_user_pages(pages, nr_pages);
 	} else {
-- 
2.32.0

[PATCH v5 03/10] mm/gup: fail get_user_pages for LONGTERM dev coherent type

[Alex Sierra]

Avoid long term pinning for Coherent device type pages. This could
interfere with their own device memory manager. For now, we are just
returning error for PIN_LONGTERM Coherent device type pages. Eventually,
these type of pages will get migrated to system memory, once the device
migration pages support is added.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 mm/gup.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index f0af462ac1e2..f596b932d7d7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1864,6 +1864,12 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 		 * If we get a movable page, since we are going to be pinning
 		 * these entries, try to move them out if possible.
 		 */
+		if (is_dev_private_or_coherent_page(head)) {
+			WARN_ON_ONCE(is_device_private_page(head));
+			ret = -EFAULT;
+			goto unpin_pages;
+		}
+
 		if (!is_pinnable_page(head)) {
 			if (PageHuge(head)) {
 				if (!isolate_huge_page(head, &movable_page_list))
@@ -1894,6 +1900,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 	if (list_empty(&movable_page_list) && !isolation_error_count)
 		return nr_pages;
 
+unpin_pages:
 	if (gup_flags & FOLL_PIN) {
 		unpin_user_pages(pages, nr_pages);
 	} else {
-- 
2.32.0

[PATCH v5 04/10] drm/amdkfd: add SPM support for SVM

[Alex Sierra]

When CPU is connected throug XGMI, it has coherent
access to VRAM resource. In this case that resource
is taken from a table in the device gmc aperture base.
This resource is used along with the device type, which could
be DEVICE_PRIVATE or DEVICE_COHERENT to create the device
page map region.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 29 +++++++++++++++---------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index ed5385137f48..5e8d944d359e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -933,7 +933,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
 {
 	struct kfd_dev *kfddev = adev->kfd.dev;
 	struct dev_pagemap *pgmap;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long size;
 	void *r;
 
@@ -948,28 +948,34 @@ int svm_migrate_init(struct amdgpu_device *adev)
 	 * should remove reserved size
 	 */
 	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
-	res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
-	if (IS_ERR(res))
-		return -ENOMEM;
+	if (adev->gmc.xgmi.connected_to_cpu) {
+		pgmap->range.start = adev->gmc.aper_base;
+		pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 1;
+		pgmap->type = MEMORY_DEVICE_COHERENT;
+	} else {
+		res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+		if (IS_ERR(res))
+			return -ENOMEM;
+		pgmap->range.start = res->start;
+		pgmap->range.end = res->end;
+		pgmap->type = MEMORY_DEVICE_PRIVATE;
+	}
 
-	pgmap->type = MEMORY_DEVICE_PRIVATE;
 	pgmap->nr_range = 1;
-	pgmap->range.start = res->start;
-	pgmap->range.end = res->end;
 	pgmap->ops = &svm_migrate_pgmap_ops;
 	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
-	pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
-
+	pgmap->flags = 0;
 	/* Device manager releases device-specific resources, memory region and
 	 * pgmap when driver disconnects from device.
 	 */
 	r = devm_memremap_pages(adev->dev, pgmap);
 	if (IS_ERR(r)) {
 		pr_err("failed to register HMM device memory\n");
-
 		/* Disable SVM support capability */
 		pgmap->type = 0;
-		devm_release_mem_region(adev->dev, res->start, resource_size(res));
+		if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+			devm_release_mem_region(adev->dev, res->start,
+						res->end - res->start + 1);
 		return PTR_ERR(r);
 	}
 
@@ -982,3 +988,4 @@ int svm_migrate_init(struct amdgpu_device *adev)
 
 	return 0;
 }
+
-- 
2.32.0

[PATCH v5 04/10] drm/amdkfd: add SPM support for SVM

[Alex Sierra]

When CPU is connected throug XGMI, it has coherent
access to VRAM resource. In this case that resource
is taken from a table in the device gmc aperture base.
This resource is used along with the device type, which could
be DEVICE_PRIVATE or DEVICE_COHERENT to create the device
page map region.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 29 +++++++++++++++---------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index ed5385137f48..5e8d944d359e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -933,7 +933,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
 {
 	struct kfd_dev *kfddev = adev->kfd.dev;
 	struct dev_pagemap *pgmap;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long size;
 	void *r;
 
@@ -948,28 +948,34 @@ int svm_migrate_init(struct amdgpu_device *adev)
 	 * should remove reserved size
 	 */
 	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
-	res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
-	if (IS_ERR(res))
-		return -ENOMEM;
+	if (adev->gmc.xgmi.connected_to_cpu) {
+		pgmap->range.start = adev->gmc.aper_base;
+		pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 1;
+		pgmap->type = MEMORY_DEVICE_COHERENT;
+	} else {
+		res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+		if (IS_ERR(res))
+			return -ENOMEM;
+		pgmap->range.start = res->start;
+		pgmap->range.end = res->end;
+		pgmap->type = MEMORY_DEVICE_PRIVATE;
+	}
 
-	pgmap->type = MEMORY_DEVICE_PRIVATE;
 	pgmap->nr_range = 1;
-	pgmap->range.start = res->start;
-	pgmap->range.end = res->end;
 	pgmap->ops = &svm_migrate_pgmap_ops;
 	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
-	pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
-
+	pgmap->flags = 0;
 	/* Device manager releases device-specific resources, memory region and
 	 * pgmap when driver disconnects from device.
 	 */
 	r = devm_memremap_pages(adev->dev, pgmap);
 	if (IS_ERR(r)) {
 		pr_err("failed to register HMM device memory\n");
-
 		/* Disable SVM support capability */
 		pgmap->type = 0;
-		devm_release_mem_region(adev->dev, res->start, resource_size(res));
+		if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+			devm_release_mem_region(adev->dev, res->start,
+						res->end - res->start + 1);
 		return PTR_ERR(r);
 	}
 
@@ -982,3 +988,4 @@ int svm_migrate_init(struct amdgpu_device *adev)
 
 	return 0;
 }
+
-- 
2.32.0

[PATCH v5 05/10] drm/amdkfd: coherent type as sys mem on migration to ram

[Alex Sierra]

Coherent device type memory on VRAM to RAM migration, has similar access
as System RAM from the CPU. This flag sets the source from the sender.
Which in Coherent type case, should be set as
MIGRATE_VMA_SELECT_DEVICE_COHERENT.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 5e8d944d359e..846ba55723fb 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -659,9 +659,12 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 	migrate.vma = vma;
 	migrate.start = start;
 	migrate.end = end;
-	migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
 
+	if (adev->gmc.xgmi.connected_to_cpu)
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+	else
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
 	size *= npages;
 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
-- 
2.32.0

[PATCH v5 05/10] drm/amdkfd: coherent type as sys mem on migration to ram

[Alex Sierra]

Coherent device type memory on VRAM to RAM migration, has similar access
as System RAM from the CPU. This flag sets the source from the sender.
Which in Coherent type case, should be set as
MIGRATE_VMA_SELECT_DEVICE_COHERENT.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 5e8d944d359e..846ba55723fb 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -659,9 +659,12 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 	migrate.vma = vma;
 	migrate.start = start;
 	migrate.end = end;
-	migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
 
+	if (adev->gmc.xgmi.connected_to_cpu)
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+	else
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 	size = 2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t);
 	size *= npages;
 	buf = kvmalloc(size, GFP_KERNEL | __GFP_ZERO);
-- 
2.32.0

[PATCH v5 06/10] lib: test_hmm add ioctl to get zone device type

[Alex Sierra]

new ioctl cmd added to query zone device type. This will be
used once the test_hmm adds zone device coherent type.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 lib/test_hmm.c      | 23 +++++++++++++++++++++--
 lib/test_hmm_uapi.h |  8 ++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 767538089a62..556bd80ce22e 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -84,6 +84,7 @@ struct dmirror_chunk {
 struct dmirror_device {
 	struct cdev		cdevice;
 	struct hmm_devmem	*devmem;
+	unsigned int            zone_device_type;
 
 	unsigned int		devmem_capacity;
 	unsigned int		devmem_count;
@@ -1024,6 +1025,15 @@ static int dmirror_snapshot(struct dmirror *dmirror,
 	return ret;
 }
 
+static int dmirror_get_device_type(struct dmirror *dmirror,
+			    struct hmm_dmirror_cmd *cmd)
+{
+	mutex_lock(&dmirror->mutex);
+	cmd->zone_device_type = dmirror->mdevice->zone_device_type;
+	mutex_unlock(&dmirror->mutex);
+
+	return 0;
+}
 static long dmirror_fops_unlocked_ioctl(struct file *filp,
 					unsigned int command,
 					unsigned long arg)
@@ -1074,6 +1084,9 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
 		ret = dmirror_snapshot(dmirror, &cmd);
 		break;
 
+	case HMM_DMIRROR_GET_MEM_DEV_TYPE:
+		ret = dmirror_get_device_type(dmirror, &cmd);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -1258,14 +1271,20 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
 static int __init hmm_dmirror_init(void)
 {
 	int ret;
-	int id;
+	int id = 0;
+	int ndevices = 0;
 
 	ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
 				  "HMM_DMIRROR");
 	if (ret)
 		goto err_unreg;
 
-	for (id = 0; id < DMIRROR_NDEVICES; id++) {
+	memset(dmirror_devices, 0, DMIRROR_NDEVICES * sizeof(dmirror_devices[0]));
+	dmirror_devices[ndevices++].zone_device_type =
+				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	dmirror_devices[ndevices++].zone_device_type =
+				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	for (id = 0; id < ndevices; id++) {
 		ret = dmirror_device_init(dmirror_devices + id, id);
 		if (ret)
 			goto err_chrdev;
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index f14dea5dcd06..17f842f1aa02 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -19,6 +19,7 @@
  * @npages: (in) number of pages to read/write
  * @cpages: (out) number of pages copied
  * @faults: (out) number of device page faults seen
+ * @zone_device_type: (out) zone device memory type
  */
 struct hmm_dmirror_cmd {
 	__u64		addr;
@@ -26,6 +27,7 @@ struct hmm_dmirror_cmd {
 	__u64		npages;
 	__u64		cpages;
 	__u64		faults;
+	__u64		zone_device_type;
 };
 
 /* Expose the address space of the calling process through hmm device file */
@@ -35,6 +37,7 @@ struct hmm_dmirror_cmd {
 #define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x03, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
 
 /*
  * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -62,4 +65,9 @@ enum {
 	HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE	= 0x30,
 };
 
+enum {
+	/* 0 is reserved to catch uninitialized type fields */
+	HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+};
+
 #endif /* _LIB_TEST_HMM_UAPI_H */
-- 
2.32.0

[PATCH v5 06/10] lib: test_hmm add ioctl to get zone device type

[Alex Sierra]

new ioctl cmd added to query zone device type. This will be
used once the test_hmm adds zone device coherent type.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 lib/test_hmm.c      | 23 +++++++++++++++++++++--
 lib/test_hmm_uapi.h |  8 ++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 767538089a62..556bd80ce22e 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -84,6 +84,7 @@ struct dmirror_chunk {
 struct dmirror_device {
 	struct cdev		cdevice;
 	struct hmm_devmem	*devmem;
+	unsigned int            zone_device_type;
 
 	unsigned int		devmem_capacity;
 	unsigned int		devmem_count;
@@ -1024,6 +1025,15 @@ static int dmirror_snapshot(struct dmirror *dmirror,
 	return ret;
 }
 
+static int dmirror_get_device_type(struct dmirror *dmirror,
+			    struct hmm_dmirror_cmd *cmd)
+{
+	mutex_lock(&dmirror->mutex);
+	cmd->zone_device_type = dmirror->mdevice->zone_device_type;
+	mutex_unlock(&dmirror->mutex);
+
+	return 0;
+}
 static long dmirror_fops_unlocked_ioctl(struct file *filp,
 					unsigned int command,
 					unsigned long arg)
@@ -1074,6 +1084,9 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
 		ret = dmirror_snapshot(dmirror, &cmd);
 		break;
 
+	case HMM_DMIRROR_GET_MEM_DEV_TYPE:
+		ret = dmirror_get_device_type(dmirror, &cmd);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -1258,14 +1271,20 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
 static int __init hmm_dmirror_init(void)
 {
 	int ret;
-	int id;
+	int id = 0;
+	int ndevices = 0;
 
 	ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
 				  "HMM_DMIRROR");
 	if (ret)
 		goto err_unreg;
 
-	for (id = 0; id < DMIRROR_NDEVICES; id++) {
+	memset(dmirror_devices, 0, DMIRROR_NDEVICES * sizeof(dmirror_devices[0]));
+	dmirror_devices[ndevices++].zone_device_type =
+				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	dmirror_devices[ndevices++].zone_device_type =
+				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	for (id = 0; id < ndevices; id++) {
 		ret = dmirror_device_init(dmirror_devices + id, id);
 		if (ret)
 			goto err_chrdev;
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index f14dea5dcd06..17f842f1aa02 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -19,6 +19,7 @@
  * @npages: (in) number of pages to read/write
  * @cpages: (out) number of pages copied
  * @faults: (out) number of device page faults seen
+ * @zone_device_type: (out) zone device memory type
  */
 struct hmm_dmirror_cmd {
 	__u64		addr;
@@ -26,6 +27,7 @@ struct hmm_dmirror_cmd {
 	__u64		npages;
 	__u64		cpages;
 	__u64		faults;
+	__u64		zone_device_type;
 };
 
 /* Expose the address space of the calling process through hmm device file */
@@ -35,6 +37,7 @@ struct hmm_dmirror_cmd {
 #define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x03, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
 
 /*
  * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -62,4 +65,9 @@ enum {
 	HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE	= 0x30,
 };
 
+enum {
+	/* 0 is reserved to catch uninitialized type fields */
+	HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+};
+
 #endif /* _LIB_TEST_HMM_UAPI_H */
-- 
2.32.0

[PATCH v5 07/10] lib: test_hmm add module param for zone device type

[Alex Sierra]

In order to configure device coherent in test_hmm, two module parameters
should be passed, which correspond to the SP start address of each
device (2) spm_addr_dev0 & spm_addr_dev1. If no parameters are passed,
private device type is configured.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 lib/test_hmm.c      | 73 ++++++++++++++++++++++++++++++++-------------
 lib/test_hmm_uapi.h |  1 +
 2 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 556bd80ce22e..c7f8d00e7b95 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -34,6 +34,16 @@
 #define DEVMEM_CHUNK_SIZE		(256 * 1024 * 1024U)
 #define DEVMEM_CHUNKS_RESERVE		16
 
+static unsigned long spm_addr_dev0;
+module_param(spm_addr_dev0, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev0,
+		"Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
+static unsigned long spm_addr_dev1;
+module_param(spm_addr_dev1, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev1,
+		"Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
 static const struct dev_pagemap_ops dmirror_devmem_ops;
 static const struct mmu_interval_notifier_ops dmirror_min_ops;
 static dev_t dmirror_dev;
@@ -452,28 +462,44 @@ static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
 	return ret;
 }
 
-static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 				   struct page **ppage)
 {
 	struct dmirror_chunk *devmem;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long pfn;
 	unsigned long pfn_first;
 	unsigned long pfn_last;
 	void *ptr;
+	int ret = -ENOMEM;
 
 	devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
 	if (!devmem)
-		return false;
+		return ret;
 
-	res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
-				      "hmm_dmirror");
-	if (IS_ERR(res))
+	switch (mdevice->zone_device_type) {
+	case HMM_DMIRROR_MEMORY_DEVICE_PRIVATE:
+		res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
+					      "hmm_dmirror");
+		if (IS_ERR_OR_NULL(res))
+			goto err_devmem;
+		devmem->pagemap.range.start = res->start;
+		devmem->pagemap.range.end = res->end;
+		devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+		break;
+	case HMM_DMIRROR_MEMORY_DEVICE_COHERENT:
+		devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ?
+							spm_addr_dev0 :
+							spm_addr_dev1;
+		devmem->pagemap.range.end = devmem->pagemap.range.start +
+					    DEVMEM_CHUNK_SIZE - 1;
+		devmem->pagemap.type = MEMORY_DEVICE_COHERENT;
+		break;
+	default:
+		ret = -EINVAL;
 		goto err_devmem;
+	}
 
-	devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
-	devmem->pagemap.range.start = res->start;
-	devmem->pagemap.range.end = res->end;
 	devmem->pagemap.nr_range = 1;
 	devmem->pagemap.ops = &dmirror_devmem_ops;
 	devmem->pagemap.owner = mdevice;
@@ -494,10 +520,14 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 		mdevice->devmem_capacity = new_capacity;
 		mdevice->devmem_chunks = new_chunks;
 	}
-
 	ptr = memremap_pages(&devmem->pagemap, numa_node_id());
-	if (IS_ERR(ptr))
+	if (IS_ERR_OR_NULL(ptr)) {
+		if (ptr)
+			ret = PTR_ERR(ptr);
+		else
+			ret = -EFAULT;
 		goto err_release;
+	}
 
 	devmem->mdevice = mdevice;
 	pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT;
@@ -526,15 +556,17 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 	}
 	spin_unlock(&mdevice->lock);
 
-	return true;
+	return 0;
 
 err_release:
 	mutex_unlock(&mdevice->devmem_lock);
-	release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
+	if (res && devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+		release_mem_region(devmem->pagemap.range.start,
+				   range_len(&devmem->pagemap.range));
 err_devmem:
 	kfree(devmem);
 
-	return false;
+	return ret;
 }
 
 static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
@@ -559,7 +591,7 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 		spin_unlock(&mdevice->lock);
 	} else {
 		spin_unlock(&mdevice->lock);
-		if (!dmirror_allocate_chunk(mdevice, &dpage))
+		if (dmirror_allocate_chunk(mdevice, &dpage))
 			goto error;
 	}
 
@@ -1242,10 +1274,8 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
 	if (ret)
 		return ret;
 
-	/* Build a list of free ZONE_DEVICE private struct pages */
-	dmirror_allocate_chunk(mdevice, NULL);
-
-	return 0;
+	/* Build a list of free ZONE_DEVICE struct pages */
+	return dmirror_allocate_chunk(mdevice, NULL);
 }
 
 static void dmirror_device_remove(struct dmirror_device *mdevice)
@@ -1258,8 +1288,9 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
 				mdevice->devmem_chunks[i];
 
 			memunmap_pages(&devmem->pagemap);
-			release_mem_region(devmem->pagemap.range.start,
-					   range_len(&devmem->pagemap.range));
+			if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+				release_mem_region(devmem->pagemap.range.start,
+						   range_len(&devmem->pagemap.range));
 			kfree(devmem);
 		}
 		kfree(mdevice->devmem_chunks);
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 17f842f1aa02..625f3690d086 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -68,6 +68,7 @@ enum {
 enum {
 	/* 0 is reserved to catch uninitialized type fields */
 	HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+	HMM_DMIRROR_MEMORY_DEVICE_COHERENT,
 };
 
 #endif /* _LIB_TEST_HMM_UAPI_H */
-- 
2.32.0

[PATCH v5 07/10] lib: test_hmm add module param for zone device type

[Alex Sierra]

In order to configure device coherent in test_hmm, two module parameters
should be passed, which correspond to the SP start address of each
device (2) spm_addr_dev0 & spm_addr_dev1. If no parameters are passed,
private device type is configured.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
 lib/test_hmm.c      | 73 ++++++++++++++++++++++++++++++++-------------
 lib/test_hmm_uapi.h |  1 +
 2 files changed, 53 insertions(+), 21 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 556bd80ce22e..c7f8d00e7b95 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -34,6 +34,16 @@
 #define DEVMEM_CHUNK_SIZE		(256 * 1024 * 1024U)
 #define DEVMEM_CHUNKS_RESERVE		16
 
+static unsigned long spm_addr_dev0;
+module_param(spm_addr_dev0, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev0,
+		"Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
+static unsigned long spm_addr_dev1;
+module_param(spm_addr_dev1, long, 0644);
+MODULE_PARM_DESC(spm_addr_dev1,
+		"Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
+
 static const struct dev_pagemap_ops dmirror_devmem_ops;
 static const struct mmu_interval_notifier_ops dmirror_min_ops;
 static dev_t dmirror_dev;
@@ -452,28 +462,44 @@ static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
 	return ret;
 }
 
-static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 				   struct page **ppage)
 {
 	struct dmirror_chunk *devmem;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long pfn;
 	unsigned long pfn_first;
 	unsigned long pfn_last;
 	void *ptr;
+	int ret = -ENOMEM;
 
 	devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
 	if (!devmem)
-		return false;
+		return ret;
 
-	res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
-				      "hmm_dmirror");
-	if (IS_ERR(res))
+	switch (mdevice->zone_device_type) {
+	case HMM_DMIRROR_MEMORY_DEVICE_PRIVATE:
+		res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
+					      "hmm_dmirror");
+		if (IS_ERR_OR_NULL(res))
+			goto err_devmem;
+		devmem->pagemap.range.start = res->start;
+		devmem->pagemap.range.end = res->end;
+		devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+		break;
+	case HMM_DMIRROR_MEMORY_DEVICE_COHERENT:
+		devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ?
+							spm_addr_dev0 :
+							spm_addr_dev1;
+		devmem->pagemap.range.end = devmem->pagemap.range.start +
+					    DEVMEM_CHUNK_SIZE - 1;
+		devmem->pagemap.type = MEMORY_DEVICE_COHERENT;
+		break;
+	default:
+		ret = -EINVAL;
 		goto err_devmem;
+	}
 
-	devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
-	devmem->pagemap.range.start = res->start;
-	devmem->pagemap.range.end = res->end;
 	devmem->pagemap.nr_range = 1;
 	devmem->pagemap.ops = &dmirror_devmem_ops;
 	devmem->pagemap.owner = mdevice;
@@ -494,10 +520,14 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 		mdevice->devmem_capacity = new_capacity;
 		mdevice->devmem_chunks = new_chunks;
 	}
-
 	ptr = memremap_pages(&devmem->pagemap, numa_node_id());
-	if (IS_ERR(ptr))
+	if (IS_ERR_OR_NULL(ptr)) {
+		if (ptr)
+			ret = PTR_ERR(ptr);
+		else
+			ret = -EFAULT;
 		goto err_release;
+	}
 
 	devmem->mdevice = mdevice;
 	pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT;
@@ -526,15 +556,17 @@ static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
 	}
 	spin_unlock(&mdevice->lock);
 
-	return true;
+	return 0;
 
 err_release:
 	mutex_unlock(&mdevice->devmem_lock);
-	release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range));
+	if (res && devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+		release_mem_region(devmem->pagemap.range.start,
+				   range_len(&devmem->pagemap.range));
 err_devmem:
 	kfree(devmem);
 
-	return false;
+	return ret;
 }
 
 static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
@@ -559,7 +591,7 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 		spin_unlock(&mdevice->lock);
 	} else {
 		spin_unlock(&mdevice->lock);
-		if (!dmirror_allocate_chunk(mdevice, &dpage))
+		if (dmirror_allocate_chunk(mdevice, &dpage))
 			goto error;
 	}
 
@@ -1242,10 +1274,8 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
 	if (ret)
 		return ret;
 
-	/* Build a list of free ZONE_DEVICE private struct pages */
-	dmirror_allocate_chunk(mdevice, NULL);
-
-	return 0;
+	/* Build a list of free ZONE_DEVICE struct pages */
+	return dmirror_allocate_chunk(mdevice, NULL);
 }
 
 static void dmirror_device_remove(struct dmirror_device *mdevice)
@@ -1258,8 +1288,9 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
 				mdevice->devmem_chunks[i];
 
 			memunmap_pages(&devmem->pagemap);
-			release_mem_region(devmem->pagemap.range.start,
-					   range_len(&devmem->pagemap.range));
+			if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+				release_mem_region(devmem->pagemap.range.start,
+						   range_len(&devmem->pagemap.range));
 			kfree(devmem);
 		}
 		kfree(mdevice->devmem_chunks);
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 17f842f1aa02..625f3690d086 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -68,6 +68,7 @@ enum {
 enum {
 	/* 0 is reserved to catch uninitialized type fields */
 	HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
+	HMM_DMIRROR_MEMORY_DEVICE_COHERENT,
 };
 
 #endif /* _LIB_TEST_HMM_UAPI_H */
-- 
2.32.0

[PATCH v5 08/10] lib: add support for device coherent type in test_hmm

[Alex Sierra]

Device Coherent type uses device memory that is coherently accesible by
the CPU. This could be shown as SP (special purpose) memory range
at the BIOS-e820 memory enumeration. If no SP memory is supported in
system, this could be faked by setting CONFIG_EFI_FAKE_MEMMAP.

Currently, test_hmm only supports two different SP ranges of at least
256MB size. This could be specified in the kernel parameter variable
efi_fake_mem. Ex. Two SP ranges of 1GB starting at 0x100000000 &
0x140000000 physical address. Ex.
efi_fake_mem=1G@0x100000000:0x40000,1G@0x140000000:0x40000

Private and coherent device mirror instances can be created in the same
probed. This is done by passing the module parameters spm_addr_dev0 &
spm_addr_dev1. In this case, it will create four instances of
device_mirror. The first two correspond to private device type, the
last two to coherent type. Then, they can be easily accessed from user
space through /dev/hmm_mirror<num_device>. Usually num_device 0 and 1
are for private, and 2 and 3 for coherent types. If no module
parameters are passed, two instances of private type device_mirror will
be created only.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
v4:
Return number of coherent device pages successfully migrated to system.
This is returned at cmd->cpages.
---
 lib/test_hmm.c      | 260 +++++++++++++++++++++++++++++++++-----------
 lib/test_hmm_uapi.h |  15 ++-
 2 files changed, 205 insertions(+), 70 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index c7f8d00e7b95..dedce7908ac6 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -29,11 +29,22 @@
 
 #include "test_hmm_uapi.h"
 
-#define DMIRROR_NDEVICES		2
+#define DMIRROR_NDEVICES		4
 #define DMIRROR_RANGE_FAULT_TIMEOUT	1000
 #define DEVMEM_CHUNK_SIZE		(256 * 1024 * 1024U)
 #define DEVMEM_CHUNKS_RESERVE		16
 
+/*
+ * For device_private pages, dpage is just a dummy struct page
+ * representing a piece of device memory. dmirror_devmem_alloc_page
+ * allocates a real system memory page as backing storage to fake a
+ * real device. zone_device_data points to that backing page. But
+ * for device_coherent memory, the struct page represents real
+ * physical CPU-accessible memory that we can use directly.
+ */
+#define BACKING_PAGE(page) (is_device_private_page((page)) ? \
+			   (page)->zone_device_data : (page))
+
 static unsigned long spm_addr_dev0;
 module_param(spm_addr_dev0, long, 0644);
 MODULE_PARM_DESC(spm_addr_dev0,
@@ -122,6 +133,21 @@ static int dmirror_bounce_init(struct dmirror_bounce *bounce,
 	return 0;
 }
 
+static bool dmirror_is_private_zone(struct dmirror_device *mdevice)
+{
+	return (mdevice->zone_device_type ==
+		HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ? true : false;
+}
+
+static enum migrate_vma_direction
+	dmirror_select_device(struct dmirror *dmirror)
+{
+	return (dmirror->mdevice->zone_device_type ==
+		HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ?
+		MIGRATE_VMA_SELECT_DEVICE_PRIVATE :
+		MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+}
+
 static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
 {
 	vfree(bounce->ptr);
@@ -572,16 +598,19 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 {
 	struct page *dpage = NULL;
-	struct page *rpage;
+	struct page *rpage = NULL;
 
 	/*
-	 * This is a fake device so we alloc real system memory to store
-	 * our device memory.
+	 * For ZONE_DEVICE private type, this is a fake device so we alloc real
+	 * system memory to store our device memory.
+	 * For ZONE_DEVICE coherent type we use the actual dpage to store the data
+	 * and ignore rpage.
 	 */
-	rpage = alloc_page(GFP_HIGHUSER);
-	if (!rpage)
-		return NULL;
-
+	if (dmirror_is_private_zone(mdevice)) {
+		rpage = alloc_page(GFP_HIGHUSER);
+		if (!rpage)
+			return NULL;
+	}
 	spin_lock(&mdevice->lock);
 
 	if (mdevice->free_pages) {
@@ -601,7 +630,8 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 	return dpage;
 
 error:
-	__free_page(rpage);
+	if (rpage)
+		__free_page(rpage);
 	return NULL;
 }
 
@@ -627,12 +657,16 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
 		 * unallocated pte_none() or read-only zero page.
 		 */
 		spage = migrate_pfn_to_page(*src);
+		if (WARN(spage && is_zone_device_page(spage),
+		     "page already in device spage pfn: 0x%lx\n",
+		     page_to_pfn(spage)))
+			continue;
 
 		dpage = dmirror_devmem_alloc_page(mdevice);
 		if (!dpage)
 			continue;
 
-		rpage = dpage->zone_device_data;
+		rpage = BACKING_PAGE(dpage);
 		if (spage)
 			copy_highpage(rpage, spage);
 		else
@@ -646,6 +680,8 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
 		 */
 		rpage->zone_device_data = dmirror;
 
+		pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
+			 page_to_pfn(spage), page_to_pfn(dpage));
 		*dst = migrate_pfn(page_to_pfn(dpage));
 		if ((*src & MIGRATE_PFN_WRITE) ||
 		    (!spage && args->vma->vm_flags & VM_WRITE))
@@ -723,11 +759,7 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
 		if (!dpage)
 			continue;
 
-		/*
-		 * Store the page that holds the data so the page table
-		 * doesn't have to deal with ZONE_DEVICE private pages.
-		 */
-		entry = dpage->zone_device_data;
+		entry = BACKING_PAGE(dpage);
 		if (*dst & MIGRATE_PFN_WRITE)
 			entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
 		entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
@@ -807,15 +839,124 @@ static int dmirror_exclusive(struct dmirror *dmirror,
 	return ret;
 }
 
-static int dmirror_migrate(struct dmirror *dmirror,
-			   struct hmm_dmirror_cmd *cmd)
+static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
+						      struct dmirror *dmirror)
+{
+	const unsigned long *src = args->src;
+	unsigned long *dst = args->dst;
+	unsigned long start = args->start;
+	unsigned long end = args->end;
+	unsigned long addr;
+
+	for (addr = start; addr < end; addr += PAGE_SIZE,
+				       src++, dst++) {
+		struct page *dpage, *spage;
+
+		spage = migrate_pfn_to_page(*src);
+		if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
+			continue;
+
+		if (WARN_ON(!is_dev_private_or_coherent_page(spage)))
+			continue;
+		spage = BACKING_PAGE(spage);
+		dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
+		if (!dpage)
+			continue;
+		pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
+			 page_to_pfn(spage), page_to_pfn(dpage));
+
+		lock_page(dpage);
+		xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
+		copy_highpage(dpage, spage);
+		*dst = migrate_pfn(page_to_pfn(dpage));
+		if (*src & MIGRATE_PFN_WRITE)
+			*dst |= MIGRATE_PFN_WRITE;
+	}
+	return 0;
+}
+
+static unsigned long dmirror_successful_migrated_pages(struct migrate_vma *migrate)
+{
+	unsigned long cpages = 0;
+	unsigned long i;
+
+	for (i = 0; i < migrate->npages; i++) {
+		if (migrate->src[i] & MIGRATE_PFN_VALID &&
+		    migrate->src[i] & MIGRATE_PFN_MIGRATE)
+			cpages++;
+	}
+	return cpages;
+}
+
+static int dmirror_migrate_to_system(struct dmirror *dmirror,
+				     struct hmm_dmirror_cmd *cmd)
+{
+	unsigned long start, end, addr;
+	unsigned long size = cmd->npages << PAGE_SHIFT;
+	struct mm_struct *mm = dmirror->notifier.mm;
+	struct vm_area_struct *vma;
+	unsigned long src_pfns[64] = { 0 };
+	unsigned long dst_pfns[64] = { 0 };
+	struct migrate_vma args;
+	unsigned long next;
+	int ret;
+
+	start = cmd->addr;
+	end = start + size;
+	if (end < start)
+		return -EINVAL;
+
+	/* Since the mm is for the mirrored process, get a reference first. */
+	if (!mmget_not_zero(mm))
+		return -EINVAL;
+
+	cmd->cpages = 0;
+	mmap_read_lock(mm);
+	for (addr = start; addr < end; addr = next) {
+		vma = vma_lookup(mm, addr);
+		if (!vma || !(vma->vm_flags & VM_READ)) {
+			ret = -EINVAL;
+			goto out;
+		}
+		next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+		if (next > vma->vm_end)
+			next = vma->vm_end;
+
+		args.vma = vma;
+		args.src = src_pfns;
+		args.dst = dst_pfns;
+		args.start = addr;
+		args.end = next;
+		args.pgmap_owner = dmirror->mdevice;
+		args.flags = dmirror_select_device(dmirror);
+
+		ret = migrate_vma_setup(&args);
+		if (ret)
+			goto out;
+
+		pr_debug("Migrating from device mem to sys mem\n");
+		dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
+
+		migrate_vma_pages(&args);
+		cmd->cpages += dmirror_successful_migrated_pages(&args);
+		migrate_vma_finalize(&args);
+	}
+out:
+	mmap_read_unlock(mm);
+	mmput(mm);
+
+	return ret;
+}
+
+static int dmirror_migrate_to_device(struct dmirror *dmirror,
+				struct hmm_dmirror_cmd *cmd)
 {
 	unsigned long start, end, addr;
 	unsigned long size = cmd->npages << PAGE_SHIFT;
 	struct mm_struct *mm = dmirror->notifier.mm;
 	struct vm_area_struct *vma;
-	unsigned long src_pfns[64];
-	unsigned long dst_pfns[64];
+	unsigned long src_pfns[64] = { 0 };
+	unsigned long dst_pfns[64] = { 0 };
 	struct dmirror_bounce bounce;
 	struct migrate_vma args;
 	unsigned long next;
@@ -852,6 +993,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
 		if (ret)
 			goto out;
 
+		pr_debug("Migrating from sys mem to device mem\n");
 		dmirror_migrate_alloc_and_copy(&args, dmirror);
 		migrate_vma_pages(&args);
 		dmirror_migrate_finalize_and_map(&args, dmirror);
@@ -860,7 +1002,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
 	mmap_read_unlock(mm);
 	mmput(mm);
 
-	/* Return the migrated data for verification. */
+	/* Return the migrated data for verification. only for pages in device zone */
 	ret = dmirror_bounce_init(&bounce, start, size);
 	if (ret)
 		return ret;
@@ -897,12 +1039,22 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
 	}
 
 	page = hmm_pfn_to_page(entry);
-	if (is_device_private_page(page)) {
-		/* Is the page migrated to this device or some other? */
-		if (dmirror->mdevice == dmirror_page_to_device(page))
+	if (is_dev_private_or_coherent_page(page)) {
+		/* Is page ZONE_DEVICE coherent? */
+		if (is_device_coherent_page(page)) {
+			if (dmirror->mdevice == dmirror_page_to_device(page))
+				*perm = HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL;
+			else
+				*perm = HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE;
+		/*
+		 * Is page ZONE_DEVICE private migrated to
+		 * this device or some other?
+		 */
+		} else if (dmirror->mdevice == dmirror_page_to_device(page)) {
 			*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
-		else
+		} else {
 			*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
+		}
 	} else if (is_zero_pfn(page_to_pfn(page)))
 		*perm = HMM_DMIRROR_PROT_ZERO;
 	else
@@ -1099,8 +1251,12 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
 		ret = dmirror_write(dmirror, &cmd);
 		break;
 
-	case HMM_DMIRROR_MIGRATE:
-		ret = dmirror_migrate(dmirror, &cmd);
+	case HMM_DMIRROR_MIGRATE_TO_DEV:
+		ret = dmirror_migrate_to_device(dmirror, &cmd);
+		break;
+
+	case HMM_DMIRROR_MIGRATE_TO_SYS:
+		ret = dmirror_migrate_to_system(dmirror, &cmd);
 		break;
 
 	case HMM_DMIRROR_EXCLUSIVE:
@@ -1165,14 +1321,13 @@ static const struct file_operations dmirror_fops = {
 
 static void dmirror_devmem_free(struct page *page)
 {
-	struct page *rpage = page->zone_device_data;
+	struct page *rpage = BACKING_PAGE(page);
 	struct dmirror_device *mdevice;
 
-	if (rpage)
+	if (rpage != page)
 		__free_page(rpage);
 
 	mdevice = dmirror_page_to_device(page);
-
 	spin_lock(&mdevice->lock);
 	mdevice->cfree++;
 	page->zone_device_data = mdevice->free_pages;
@@ -1180,43 +1335,11 @@ static void dmirror_devmem_free(struct page *page)
 	spin_unlock(&mdevice->lock);
 }
 
-static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
-						      struct dmirror *dmirror)
-{
-	const unsigned long *src = args->src;
-	unsigned long *dst = args->dst;
-	unsigned long start = args->start;
-	unsigned long end = args->end;
-	unsigned long addr;
-
-	for (addr = start; addr < end; addr += PAGE_SIZE,
-				       src++, dst++) {
-		struct page *dpage, *spage;
-
-		spage = migrate_pfn_to_page(*src);
-		if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
-			continue;
-		spage = spage->zone_device_data;
-
-		dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
-		if (!dpage)
-			continue;
-
-		lock_page(dpage);
-		xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
-		copy_highpage(dpage, spage);
-		*dst = migrate_pfn(page_to_pfn(dpage));
-		if (*src & MIGRATE_PFN_WRITE)
-			*dst |= MIGRATE_PFN_WRITE;
-	}
-	return 0;
-}
-
 static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 {
 	struct migrate_vma args;
-	unsigned long src_pfns;
-	unsigned long dst_pfns;
+	unsigned long src_pfns = 0;
+	unsigned long dst_pfns = 0;
 	struct page *rpage;
 	struct dmirror *dmirror;
 	vm_fault_t ret;
@@ -1236,7 +1359,7 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 	args.src = &src_pfns;
 	args.dst = &dst_pfns;
 	args.pgmap_owner = dmirror->mdevice;
-	args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+	args.flags = dmirror_select_device(dmirror);
 
 	if (migrate_vma_setup(&args))
 		return VM_FAULT_SIGBUS;
@@ -1315,6 +1438,12 @@ static int __init hmm_dmirror_init(void)
 				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
 	dmirror_devices[ndevices++].zone_device_type =
 				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	if (spm_addr_dev0 && spm_addr_dev1) {
+		dmirror_devices[ndevices++].zone_device_type =
+					HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+		dmirror_devices[ndevices++].zone_device_type =
+					HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+	}
 	for (id = 0; id < ndevices; id++) {
 		ret = dmirror_device_init(dmirror_devices + id, id);
 		if (ret)
@@ -1337,7 +1466,8 @@ static void __exit hmm_dmirror_exit(void)
 	int id;
 
 	for (id = 0; id < DMIRROR_NDEVICES; id++)
-		dmirror_device_remove(dmirror_devices + id);
+		if (dmirror_devices[id].zone_device_type)
+			dmirror_device_remove(dmirror_devices + id);
 	unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
 }
 
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 625f3690d086..e190b2ab6f19 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -33,11 +33,12 @@ struct hmm_dmirror_cmd {
 /* Expose the address space of the calling process through hmm device file */
 #define HMM_DMIRROR_READ		_IOWR('H', 0x00, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_WRITE		_IOWR('H', 0x01, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_MIGRATE		_IOWR('H', 0x02, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x03, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x05, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_DEV	_IOWR('H', 0x02, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_SYS	_IOWR('H', 0x03, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x07, struct hmm_dmirror_cmd)
 
 /*
  * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -52,6 +53,8 @@ struct hmm_dmirror_cmd {
  *					device the ioctl() is made
  * HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
  *					other device
+ * HMM_DMIRROR_PROT_DEV_COHERENT: Migrate device coherent page on the device
+ *				  the ioctl() is made
  */
 enum {
 	HMM_DMIRROR_PROT_ERROR			= 0xFF,
@@ -63,6 +66,8 @@ enum {
 	HMM_DMIRROR_PROT_ZERO			= 0x10,
 	HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL	= 0x20,
 	HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE	= 0x30,
+	HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL	= 0x40,
+	HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE	= 0x50,
 };
 
 enum {
-- 
2.32.0

[PATCH v5 08/10] lib: add support for device coherent type in test_hmm

[Alex Sierra]

Device Coherent type uses device memory that is coherently accesible by
the CPU. This could be shown as SP (special purpose) memory range
at the BIOS-e820 memory enumeration. If no SP memory is supported in
system, this could be faked by setting CONFIG_EFI_FAKE_MEMMAP.

Currently, test_hmm only supports two different SP ranges of at least
256MB size. This could be specified in the kernel parameter variable
efi_fake_mem. Ex. Two SP ranges of 1GB starting at 0x100000000 &
0x140000000 physical address. Ex.
efi_fake_mem=1G@0x100000000:0x40000,1G@0x140000000:0x40000

Private and coherent device mirror instances can be created in the same
probed. This is done by passing the module parameters spm_addr_dev0 &
spm_addr_dev1. In this case, it will create four instances of
device_mirror. The first two correspond to private device type, the
last two to coherent type. Then, they can be easily accessed from user
space through /dev/hmm_mirror<num_device>. Usually num_device 0 and 1
are for private, and 2 and 3 for coherent types. If no module
parameters are passed, two instances of private type device_mirror will
be created only.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
---
v4:
Return number of coherent device pages successfully migrated to system.
This is returned at cmd->cpages.
---
 lib/test_hmm.c      | 260 +++++++++++++++++++++++++++++++++-----------
 lib/test_hmm_uapi.h |  15 ++-
 2 files changed, 205 insertions(+), 70 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index c7f8d00e7b95..dedce7908ac6 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -29,11 +29,22 @@
 
 #include "test_hmm_uapi.h"
 
-#define DMIRROR_NDEVICES		2
+#define DMIRROR_NDEVICES		4
 #define DMIRROR_RANGE_FAULT_TIMEOUT	1000
 #define DEVMEM_CHUNK_SIZE		(256 * 1024 * 1024U)
 #define DEVMEM_CHUNKS_RESERVE		16
 
+/*
+ * For device_private pages, dpage is just a dummy struct page
+ * representing a piece of device memory. dmirror_devmem_alloc_page
+ * allocates a real system memory page as backing storage to fake a
+ * real device. zone_device_data points to that backing page. But
+ * for device_coherent memory, the struct page represents real
+ * physical CPU-accessible memory that we can use directly.
+ */
+#define BACKING_PAGE(page) (is_device_private_page((page)) ? \
+			   (page)->zone_device_data : (page))
+
 static unsigned long spm_addr_dev0;
 module_param(spm_addr_dev0, long, 0644);
 MODULE_PARM_DESC(spm_addr_dev0,
@@ -122,6 +133,21 @@ static int dmirror_bounce_init(struct dmirror_bounce *bounce,
 	return 0;
 }
 
+static bool dmirror_is_private_zone(struct dmirror_device *mdevice)
+{
+	return (mdevice->zone_device_type ==
+		HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ? true : false;
+}
+
+static enum migrate_vma_direction
+	dmirror_select_device(struct dmirror *dmirror)
+{
+	return (dmirror->mdevice->zone_device_type ==
+		HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ?
+		MIGRATE_VMA_SELECT_DEVICE_PRIVATE :
+		MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+}
+
 static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
 {
 	vfree(bounce->ptr);
@@ -572,16 +598,19 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 {
 	struct page *dpage = NULL;
-	struct page *rpage;
+	struct page *rpage = NULL;
 
 	/*
-	 * This is a fake device so we alloc real system memory to store
-	 * our device memory.
+	 * For ZONE_DEVICE private type, this is a fake device so we alloc real
+	 * system memory to store our device memory.
+	 * For ZONE_DEVICE coherent type we use the actual dpage to store the data
+	 * and ignore rpage.
 	 */
-	rpage = alloc_page(GFP_HIGHUSER);
-	if (!rpage)
-		return NULL;
-
+	if (dmirror_is_private_zone(mdevice)) {
+		rpage = alloc_page(GFP_HIGHUSER);
+		if (!rpage)
+			return NULL;
+	}
 	spin_lock(&mdevice->lock);
 
 	if (mdevice->free_pages) {
@@ -601,7 +630,8 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 	return dpage;
 
 error:
-	__free_page(rpage);
+	if (rpage)
+		__free_page(rpage);
 	return NULL;
 }
 
@@ -627,12 +657,16 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
 		 * unallocated pte_none() or read-only zero page.
 		 */
 		spage = migrate_pfn_to_page(*src);
+		if (WARN(spage && is_zone_device_page(spage),
+		     "page already in device spage pfn: 0x%lx\n",
+		     page_to_pfn(spage)))
+			continue;
 
 		dpage = dmirror_devmem_alloc_page(mdevice);
 		if (!dpage)
 			continue;
 
-		rpage = dpage->zone_device_data;
+		rpage = BACKING_PAGE(dpage);
 		if (spage)
 			copy_highpage(rpage, spage);
 		else
@@ -646,6 +680,8 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
 		 */
 		rpage->zone_device_data = dmirror;
 
+		pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
+			 page_to_pfn(spage), page_to_pfn(dpage));
 		*dst = migrate_pfn(page_to_pfn(dpage));
 		if ((*src & MIGRATE_PFN_WRITE) ||
 		    (!spage && args->vma->vm_flags & VM_WRITE))
@@ -723,11 +759,7 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
 		if (!dpage)
 			continue;
 
-		/*
-		 * Store the page that holds the data so the page table
-		 * doesn't have to deal with ZONE_DEVICE private pages.
-		 */
-		entry = dpage->zone_device_data;
+		entry = BACKING_PAGE(dpage);
 		if (*dst & MIGRATE_PFN_WRITE)
 			entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
 		entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
@@ -807,15 +839,124 @@ static int dmirror_exclusive(struct dmirror *dmirror,
 	return ret;
 }
 
-static int dmirror_migrate(struct dmirror *dmirror,
-			   struct hmm_dmirror_cmd *cmd)
+static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
+						      struct dmirror *dmirror)
+{
+	const unsigned long *src = args->src;
+	unsigned long *dst = args->dst;
+	unsigned long start = args->start;
+	unsigned long end = args->end;
+	unsigned long addr;
+
+	for (addr = start; addr < end; addr += PAGE_SIZE,
+				       src++, dst++) {
+		struct page *dpage, *spage;
+
+		spage = migrate_pfn_to_page(*src);
+		if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
+			continue;
+
+		if (WARN_ON(!is_dev_private_or_coherent_page(spage)))
+			continue;
+		spage = BACKING_PAGE(spage);
+		dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
+		if (!dpage)
+			continue;
+		pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
+			 page_to_pfn(spage), page_to_pfn(dpage));
+
+		lock_page(dpage);
+		xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
+		copy_highpage(dpage, spage);
+		*dst = migrate_pfn(page_to_pfn(dpage));
+		if (*src & MIGRATE_PFN_WRITE)
+			*dst |= MIGRATE_PFN_WRITE;
+	}
+	return 0;
+}
+
+static unsigned long dmirror_successful_migrated_pages(struct migrate_vma *migrate)
+{
+	unsigned long cpages = 0;
+	unsigned long i;
+
+	for (i = 0; i < migrate->npages; i++) {
+		if (migrate->src[i] & MIGRATE_PFN_VALID &&
+		    migrate->src[i] & MIGRATE_PFN_MIGRATE)
+			cpages++;
+	}
+	return cpages;
+}
+
+static int dmirror_migrate_to_system(struct dmirror *dmirror,
+				     struct hmm_dmirror_cmd *cmd)
+{
+	unsigned long start, end, addr;
+	unsigned long size = cmd->npages << PAGE_SHIFT;
+	struct mm_struct *mm = dmirror->notifier.mm;
+	struct vm_area_struct *vma;
+	unsigned long src_pfns[64] = { 0 };
+	unsigned long dst_pfns[64] = { 0 };
+	struct migrate_vma args;
+	unsigned long next;
+	int ret;
+
+	start = cmd->addr;
+	end = start + size;
+	if (end < start)
+		return -EINVAL;
+
+	/* Since the mm is for the mirrored process, get a reference first. */
+	if (!mmget_not_zero(mm))
+		return -EINVAL;
+
+	cmd->cpages = 0;
+	mmap_read_lock(mm);
+	for (addr = start; addr < end; addr = next) {
+		vma = vma_lookup(mm, addr);
+		if (!vma || !(vma->vm_flags & VM_READ)) {
+			ret = -EINVAL;
+			goto out;
+		}
+		next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+		if (next > vma->vm_end)
+			next = vma->vm_end;
+
+		args.vma = vma;
+		args.src = src_pfns;
+		args.dst = dst_pfns;
+		args.start = addr;
+		args.end = next;
+		args.pgmap_owner = dmirror->mdevice;
+		args.flags = dmirror_select_device(dmirror);
+
+		ret = migrate_vma_setup(&args);
+		if (ret)
+			goto out;
+
+		pr_debug("Migrating from device mem to sys mem\n");
+		dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
+
+		migrate_vma_pages(&args);
+		cmd->cpages += dmirror_successful_migrated_pages(&args);
+		migrate_vma_finalize(&args);
+	}
+out:
+	mmap_read_unlock(mm);
+	mmput(mm);
+
+	return ret;
+}
+
+static int dmirror_migrate_to_device(struct dmirror *dmirror,
+				struct hmm_dmirror_cmd *cmd)
 {
 	unsigned long start, end, addr;
 	unsigned long size = cmd->npages << PAGE_SHIFT;
 	struct mm_struct *mm = dmirror->notifier.mm;
 	struct vm_area_struct *vma;
-	unsigned long src_pfns[64];
-	unsigned long dst_pfns[64];
+	unsigned long src_pfns[64] = { 0 };
+	unsigned long dst_pfns[64] = { 0 };
 	struct dmirror_bounce bounce;
 	struct migrate_vma args;
 	unsigned long next;
@@ -852,6 +993,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
 		if (ret)
 			goto out;
 
+		pr_debug("Migrating from sys mem to device mem\n");
 		dmirror_migrate_alloc_and_copy(&args, dmirror);
 		migrate_vma_pages(&args);
 		dmirror_migrate_finalize_and_map(&args, dmirror);
@@ -860,7 +1002,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
 	mmap_read_unlock(mm);
 	mmput(mm);
 
-	/* Return the migrated data for verification. */
+	/* Return the migrated data for verification. only for pages in device zone */
 	ret = dmirror_bounce_init(&bounce, start, size);
 	if (ret)
 		return ret;
@@ -897,12 +1039,22 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
 	}
 
 	page = hmm_pfn_to_page(entry);
-	if (is_device_private_page(page)) {
-		/* Is the page migrated to this device or some other? */
-		if (dmirror->mdevice == dmirror_page_to_device(page))
+	if (is_dev_private_or_coherent_page(page)) {
+		/* Is page ZONE_DEVICE coherent? */
+		if (is_device_coherent_page(page)) {
+			if (dmirror->mdevice == dmirror_page_to_device(page))
+				*perm = HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL;
+			else
+				*perm = HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE;
+		/*
+		 * Is page ZONE_DEVICE private migrated to
+		 * this device or some other?
+		 */
+		} else if (dmirror->mdevice == dmirror_page_to_device(page)) {
 			*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
-		else
+		} else {
 			*perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
+		}
 	} else if (is_zero_pfn(page_to_pfn(page)))
 		*perm = HMM_DMIRROR_PROT_ZERO;
 	else
@@ -1099,8 +1251,12 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
 		ret = dmirror_write(dmirror, &cmd);
 		break;
 
-	case HMM_DMIRROR_MIGRATE:
-		ret = dmirror_migrate(dmirror, &cmd);
+	case HMM_DMIRROR_MIGRATE_TO_DEV:
+		ret = dmirror_migrate_to_device(dmirror, &cmd);
+		break;
+
+	case HMM_DMIRROR_MIGRATE_TO_SYS:
+		ret = dmirror_migrate_to_system(dmirror, &cmd);
 		break;
 
 	case HMM_DMIRROR_EXCLUSIVE:
@@ -1165,14 +1321,13 @@ static const struct file_operations dmirror_fops = {
 
 static void dmirror_devmem_free(struct page *page)
 {
-	struct page *rpage = page->zone_device_data;
+	struct page *rpage = BACKING_PAGE(page);
 	struct dmirror_device *mdevice;
 
-	if (rpage)
+	if (rpage != page)
 		__free_page(rpage);
 
 	mdevice = dmirror_page_to_device(page);
-
 	spin_lock(&mdevice->lock);
 	mdevice->cfree++;
 	page->zone_device_data = mdevice->free_pages;
@@ -1180,43 +1335,11 @@ static void dmirror_devmem_free(struct page *page)
 	spin_unlock(&mdevice->lock);
 }
 
-static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
-						      struct dmirror *dmirror)
-{
-	const unsigned long *src = args->src;
-	unsigned long *dst = args->dst;
-	unsigned long start = args->start;
-	unsigned long end = args->end;
-	unsigned long addr;
-
-	for (addr = start; addr < end; addr += PAGE_SIZE,
-				       src++, dst++) {
-		struct page *dpage, *spage;
-
-		spage = migrate_pfn_to_page(*src);
-		if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
-			continue;
-		spage = spage->zone_device_data;
-
-		dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
-		if (!dpage)
-			continue;
-
-		lock_page(dpage);
-		xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
-		copy_highpage(dpage, spage);
-		*dst = migrate_pfn(page_to_pfn(dpage));
-		if (*src & MIGRATE_PFN_WRITE)
-			*dst |= MIGRATE_PFN_WRITE;
-	}
-	return 0;
-}
-
 static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 {
 	struct migrate_vma args;
-	unsigned long src_pfns;
-	unsigned long dst_pfns;
+	unsigned long src_pfns = 0;
+	unsigned long dst_pfns = 0;
 	struct page *rpage;
 	struct dmirror *dmirror;
 	vm_fault_t ret;
@@ -1236,7 +1359,7 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 	args.src = &src_pfns;
 	args.dst = &dst_pfns;
 	args.pgmap_owner = dmirror->mdevice;
-	args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+	args.flags = dmirror_select_device(dmirror);
 
 	if (migrate_vma_setup(&args))
 		return VM_FAULT_SIGBUS;
@@ -1315,6 +1438,12 @@ static int __init hmm_dmirror_init(void)
 				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
 	dmirror_devices[ndevices++].zone_device_type =
 				HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
+	if (spm_addr_dev0 && spm_addr_dev1) {
+		dmirror_devices[ndevices++].zone_device_type =
+					HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+		dmirror_devices[ndevices++].zone_device_type =
+					HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
+	}
 	for (id = 0; id < ndevices; id++) {
 		ret = dmirror_device_init(dmirror_devices + id, id);
 		if (ret)
@@ -1337,7 +1466,8 @@ static void __exit hmm_dmirror_exit(void)
 	int id;
 
 	for (id = 0; id < DMIRROR_NDEVICES; id++)
-		dmirror_device_remove(dmirror_devices + id);
+		if (dmirror_devices[id].zone_device_type)
+			dmirror_device_remove(dmirror_devices + id);
 	unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
 }
 
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 625f3690d086..e190b2ab6f19 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -33,11 +33,12 @@ struct hmm_dmirror_cmd {
 /* Expose the address space of the calling process through hmm device file */
 #define HMM_DMIRROR_READ		_IOWR('H', 0x00, struct hmm_dmirror_cmd)
 #define HMM_DMIRROR_WRITE		_IOWR('H', 0x01, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_MIGRATE		_IOWR('H', 0x02, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x03, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x05, struct hmm_dmirror_cmd)
-#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_DEV	_IOWR('H', 0x02, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_SYS	_IOWR('H', 0x03, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_SNAPSHOT		_IOWR('H', 0x04, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_EXCLUSIVE		_IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_CHECK_EXCLUSIVE	_IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_GET_MEM_DEV_TYPE	_IOWR('H', 0x07, struct hmm_dmirror_cmd)
 
 /*
  * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
@@ -52,6 +53,8 @@ struct hmm_dmirror_cmd {
  *					device the ioctl() is made
  * HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
  *					other device
+ * HMM_DMIRROR_PROT_DEV_COHERENT: Migrate device coherent page on the device
+ *				  the ioctl() is made
  */
 enum {
 	HMM_DMIRROR_PROT_ERROR			= 0xFF,
@@ -63,6 +66,8 @@ enum {
 	HMM_DMIRROR_PROT_ZERO			= 0x10,
 	HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL	= 0x20,
 	HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE	= 0x30,
+	HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL	= 0x40,
+	HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE	= 0x50,
 };
 
 enum {
-- 
2.32.0

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

[Alex Sierra]

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);
 }
-- 
2.32.0

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

[Alex Sierra]

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);
 }
-- 
2.32.0

[PATCH v5 10/10] tools: update test_hmm script to support SP config

[Alex Sierra]

Add two more parameters to set spm_addr_dev0 & spm_addr_dev1
addresses. These two parameters configure the start SP
addresses for each device in test_hmm driver.
Consequently, this configures zone device type as coherent.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
---
v2:
Add more mknods for device coherent type. These are represented under
/dev/hmm_mirror2 and /dev/hmm_mirror3, only in case they have created
at probing the hmm-test driver.
---
 tools/testing/selftests/vm/test_hmm.sh | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
index 0647b525a625..539c9371e592 100755
--- a/tools/testing/selftests/vm/test_hmm.sh
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -40,11 +40,26 @@ check_test_requirements()
 
 load_driver()
 {
-	modprobe $DRIVER > /dev/null 2>&1
+	if [ $# -eq 0 ]; then
+		modprobe $DRIVER > /dev/null 2>&1
+	else
+		if [ $# -eq 2 ]; then
+			modprobe $DRIVER spm_addr_dev0=$1 spm_addr_dev1=$2
+				> /dev/null 2>&1
+		else
+			echo "Missing module parameters. Make sure pass"\
+			"spm_addr_dev0 and spm_addr_dev1"
+			usage
+		fi
+	fi
 	if [ $? == 0 ]; then
 		major=$(awk "\$2==\"HMM_DMIRROR\" {print \$1}" /proc/devices)
 		mknod /dev/hmm_dmirror0 c $major 0
 		mknod /dev/hmm_dmirror1 c $major 1
+		if [ $# -eq 2 ]; then
+			mknod /dev/hmm_dmirror2 c $major 2
+			mknod /dev/hmm_dmirror3 c $major 3
+		fi
 	fi
 }
 
@@ -58,7 +73,7 @@ run_smoke()
 {
 	echo "Running smoke test. Note, this test provides basic coverage."
 
-	load_driver
+	load_driver $1 $2
 	$(dirname "${BASH_SOURCE[0]}")/hmm-tests
 	unload_driver
 }
@@ -75,6 +90,9 @@ usage()
 	echo "# Smoke testing"
 	echo "./${TEST_NAME}.sh smoke"
 	echo
+	echo "# Smoke testing with SPM enabled"
+	echo "./${TEST_NAME}.sh smoke <spm_addr_dev0> <spm_addr_dev1>"
+	echo
 	exit 0
 }
 
@@ -84,7 +102,7 @@ function run_test()
 		usage
 	else
 		if [ "$1" = "smoke" ]; then
-			run_smoke
+			run_smoke $2 $3
 		else
 			usage
 		fi
-- 
2.32.0

[PATCH v5 10/10] tools: update test_hmm script to support SP config

[Alex Sierra]

Add two more parameters to set spm_addr_dev0 & spm_addr_dev1
addresses. These two parameters configure the start SP
addresses for each device in test_hmm driver.
Consequently, this configures zone device type as coherent.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
---
v2:
Add more mknods for device coherent type. These are represented under
/dev/hmm_mirror2 and /dev/hmm_mirror3, only in case they have created
at probing the hmm-test driver.
---
 tools/testing/selftests/vm/test_hmm.sh | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
index 0647b525a625..539c9371e592 100755
--- a/tools/testing/selftests/vm/test_hmm.sh
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -40,11 +40,26 @@ check_test_requirements()
 
 load_driver()
 {
-	modprobe $DRIVER > /dev/null 2>&1
+	if [ $# -eq 0 ]; then
+		modprobe $DRIVER > /dev/null 2>&1
+	else
+		if [ $# -eq 2 ]; then
+			modprobe $DRIVER spm_addr_dev0=$1 spm_addr_dev1=$2
+				> /dev/null 2>&1
+		else
+			echo "Missing module parameters. Make sure pass"\
+			"spm_addr_dev0 and spm_addr_dev1"
+			usage
+		fi
+	fi
 	if [ $? == 0 ]; then
 		major=$(awk "\$2==\"HMM_DMIRROR\" {print \$1}" /proc/devices)
 		mknod /dev/hmm_dmirror0 c $major 0
 		mknod /dev/hmm_dmirror1 c $major 1
+		if [ $# -eq 2 ]; then
+			mknod /dev/hmm_dmirror2 c $major 2
+			mknod /dev/hmm_dmirror3 c $major 3
+		fi
 	fi
 }
 
@@ -58,7 +73,7 @@ run_smoke()
 {
 	echo "Running smoke test. Note, this test provides basic coverage."
 
-	load_driver
+	load_driver $1 $2
 	$(dirname "${BASH_SOURCE[0]}")/hmm-tests
 	unload_driver
 }
@@ -75,6 +90,9 @@ usage()
 	echo "# Smoke testing"
 	echo "./${TEST_NAME}.sh smoke"
 	echo
+	echo "# Smoke testing with SPM enabled"
+	echo "./${TEST_NAME}.sh smoke <spm_addr_dev0> <spm_addr_dev1>"
+	echo
 	exit 0
 }
 
@@ -84,7 +102,7 @@ function run_test()
 		usage
 	else
 		if [ "$1" = "smoke" ]; then
-			run_smoke
+			run_smoke $2 $3
 		else
 			usage
 		fi
-- 
2.32.0

Re: [PATCH v5 01/10] mm: add zone device coherent type memory support

[Alistair Popple]

Looks good, feel free to add:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Saturday, 29 January 2022 7:08:16 AM AEDT Alex Sierra wrote:
> Device memory that is cache coherent from device and CPU point of view.
> This is used on platforms that have an advanced system bus (like CAPI
> or CXL). Any page of a process can be migrated to such memory. However,
> no one should be allowed to pin such memory so that it can always be
> evicted.
> 
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
> ---
> v4:
> - use the same system entry path for coherent device pages at
> migrate_vma_insert_page.
> 
> - Add coherent device type support for try_to_migrate /
> try_to_migrate_one.
> ---
>  include/linux/memremap.h |  8 +++++++
>  include/linux/mm.h       | 16 ++++++++++++++
>  mm/memcontrol.c          |  6 +++---
>  mm/memory-failure.c      |  8 +++++--
>  mm/memremap.c            | 14 ++++++++++++-
>  mm/migrate.c             | 45 ++++++++++++++++++++--------------------
>  mm/rmap.c                |  5 +++--
>  7 files changed, 71 insertions(+), 31 deletions(-)
> 
> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
> index 1fafcc38acba..727b8c789193 100644
> --- a/include/linux/memremap.h
> +++ b/include/linux/memremap.h
> @@ -39,6 +39,13 @@ struct vmem_altmap {
>   * A more complete discussion of unaddressable memory may be found in
>   * include/linux/hmm.h and Documentation/vm/hmm.rst.
>   *
> + * MEMORY_DEVICE_COHERENT:
> + * Device memory that is cache coherent from device and CPU point of view. This
> + * is used on platforms that have an advanced system bus (like CAPI or CXL). A
> + * driver can hotplug the device memory using ZONE_DEVICE and with that memory
> + * type. Any page of a process can be migrated to such memory. However no one
> + * should be allowed to pin such memory so that it can always be evicted.
> + *
>   * MEMORY_DEVICE_FS_DAX:
>   * Host memory that has similar access semantics as System RAM i.e. DMA
>   * coherent and supports page pinning. In support of coordinating page
> @@ -59,6 +66,7 @@ struct vmem_altmap {
>  enum memory_type {
>  	/* 0 is reserved to catch uninitialized type fields */
>  	MEMORY_DEVICE_PRIVATE = 1,
> +	MEMORY_DEVICE_COHERENT,
>  	MEMORY_DEVICE_FS_DAX,
>  	MEMORY_DEVICE_GENERIC,
>  	MEMORY_DEVICE_PCI_P2PDMA,
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index e1a84b1e6787..0c61bf40edef 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1106,6 +1106,7 @@ static inline bool page_is_devmap_managed(struct page *page)
>  		return false;
>  	switch (page->pgmap->type) {
>  	case MEMORY_DEVICE_PRIVATE:
> +	case MEMORY_DEVICE_COHERENT:
>  	case MEMORY_DEVICE_FS_DAX:
>  		return true;
>  	default:
> @@ -1135,6 +1136,21 @@ static inline bool is_device_private_page(const struct page *page)
>  		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
>  }
>  
> +static inline bool is_device_coherent_page(const struct page *page)
> +{
> +	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> +		is_zone_device_page(page) &&
> +		page->pgmap->type == MEMORY_DEVICE_COHERENT;
> +}
> +
> +static inline bool is_dev_private_or_coherent_page(const struct page *page)
> +{
> +	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> +		is_zone_device_page(page) &&
> +		(page->pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +		page->pgmap->type == MEMORY_DEVICE_COHERENT);
> +}
> +
>  static inline bool is_pci_p2pdma_page(const struct page *page)
>  {
>  	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 09d342c7cbd0..0882b5b2a857 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5691,8 +5691,8 @@ static int mem_cgroup_move_account(struct page *page,
>   *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
>   *     target for charge migration. if @target is not NULL, the entry is stored
>   *     in target->ent.
> - *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PRIVATE
> - *     (so ZONE_DEVICE page and thus not on the lru).
> + *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is device memory and
> + *   thus not on the lru.
>   *     For now we such page is charge like a regular page would be as for all
>   *     intent and purposes it is just special memory taking the place of a
>   *     regular page.
> @@ -5726,7 +5726,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
>  		 */
>  		if (page_memcg(page) == mc.from) {
>  			ret = MC_TARGET_PAGE;
> -			if (is_device_private_page(page))
> +			if (is_dev_private_or_coherent_page(page))
>  				ret = MC_TARGET_DEVICE;
>  			if (target)
>  				target->page = page;
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 14ae5c18e776..e83740f7f05e 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1611,12 +1611,16 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
>  		goto unlock;
>  	}
>  
> -	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
> +	switch (pgmap->type) {
> +	case MEMORY_DEVICE_PRIVATE:
> +	case MEMORY_DEVICE_COHERENT:
>  		/*
> -		 * TODO: Handle HMM pages which may need coordination
> +		 * TODO: Handle device pages which may need coordination
>  		 * with device-side memory.
>  		 */
>  		goto unlock;
> +	default:
> +		break;
>  	}
>  
>  	/*
> diff --git a/mm/memremap.c b/mm/memremap.c
> index 6aa5f0c2d11f..354c8027823f 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -44,6 +44,7 @@ EXPORT_SYMBOL(devmap_managed_key);
>  static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
>  {
>  	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +	    pgmap->type == MEMORY_DEVICE_COHERENT ||
>  	    pgmap->type == MEMORY_DEVICE_FS_DAX)
>  		static_branch_dec(&devmap_managed_key);
>  }
> @@ -51,6 +52,7 @@ static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
>  static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
>  {
>  	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +	    pgmap->type == MEMORY_DEVICE_COHERENT ||
>  	    pgmap->type == MEMORY_DEVICE_FS_DAX)
>  		static_branch_inc(&devmap_managed_key);
>  }
> @@ -327,6 +329,16 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
>  			return ERR_PTR(-EINVAL);
>  		}
>  		break;
> +	case MEMORY_DEVICE_COHERENT:
> +		if (!pgmap->ops->page_free) {
> +			WARN(1, "Missing page_free method\n");
> +			return ERR_PTR(-EINVAL);
> +		}
> +		if (!pgmap->owner) {
> +			WARN(1, "Missing owner\n");
> +			return ERR_PTR(-EINVAL);
> +		}
> +		break;
>  	case MEMORY_DEVICE_FS_DAX:
>  		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
>  		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
> @@ -469,7 +481,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
>  void free_devmap_managed_page(struct page *page)
>  {
>  	/* notify page idle for dax */
> -	if (!is_device_private_page(page)) {
> +	if (!is_dev_private_or_coherent_page(page)) {
>  		wake_up_var(&page->_refcount);
>  		return;
>  	}
> diff --git a/mm/migrate.c b/mm/migrate.c
> index c7da064b4781..cd137aedcfe5 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -345,7 +345,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
>  	 * Device private pages have an extra refcount as they are
>  	 * ZONE_DEVICE pages.
>  	 */
> -	expected_count += is_device_private_page(page);
> +	expected_count += is_dev_private_or_coherent_page(page);
>  	if (mapping)
>  		expected_count += compound_nr(page) + page_has_private(page);
>  
> @@ -2611,7 +2611,7 @@ EXPORT_SYMBOL(migrate_vma_setup);
>   *     handle_pte_fault()
>   *       do_anonymous_page()
>   * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
> - * private page.
> + * private or coherent page.
>   */
>  static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  				    unsigned long addr,
> @@ -2676,25 +2676,24 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  	 */
>  	__SetPageUptodate(page);
>  
> -	if (is_zone_device_page(page)) {
> -		if (is_device_private_page(page)) {
> -			swp_entry_t swp_entry;
> +	if (is_device_private_page(page)) {
> +		swp_entry_t swp_entry;
>  
> -			if (vma->vm_flags & VM_WRITE)
> -				swp_entry = make_writable_device_private_entry(
> -							page_to_pfn(page));
> -			else
> -				swp_entry = make_readable_device_private_entry(
> -							page_to_pfn(page));
> -			entry = swp_entry_to_pte(swp_entry);
> -		} else {
> -			/*
> -			 * For now we only support migrating to un-addressable
> -			 * device memory.
> -			 */
> -			pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
> -			goto abort;
> -		}
> +		if (vma->vm_flags & VM_WRITE)
> +			swp_entry = make_writable_device_private_entry(
> +						page_to_pfn(page));
> +		else
> +			swp_entry = make_readable_device_private_entry(
> +						page_to_pfn(page));
> +		entry = swp_entry_to_pte(swp_entry);
> +	} else if (is_zone_device_page(page) &&
> +		   !is_device_coherent_page(page)) {
> +		/*
> +		 * We support migrating to private and coherent types
> +		 * for device zone memory.
> +		 */
> +		pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
> +		goto abort;
>  	} else {
>  		entry = mk_pte(page, vma->vm_page_prot);
>  		if (vma->vm_flags & VM_WRITE)
> @@ -2796,10 +2795,10 @@ void migrate_vma_pages(struct migrate_vma *migrate)
>  		mapping = page_mapping(page);
>  
>  		if (is_zone_device_page(newpage)) {
> -			if (is_device_private_page(newpage)) {
> +			if (is_dev_private_or_coherent_page(newpage)) {
>  				/*
> -				 * For now only support private anonymous when
> -				 * migrating to un-addressable device memory.
> +				 * For now only support private and coherent
> +				 * anonymous when migrating to device memory.
>  				 */
>  				if (mapping) {
>  					migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 6a1e8c7f6213..f2bd5a3da72c 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1835,7 +1835,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
>  		/* Update high watermark before we lower rss */
>  		update_hiwater_rss(mm);
>  
> -		if (is_zone_device_page(page)) {
> +		if (is_device_private_page(page)) {
>  			unsigned long pfn = page_to_pfn(page);
>  			swp_entry_t entry;
>  			pte_t swp_pte;
> @@ -1976,7 +1976,8 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
>  					TTU_SYNC)))
>  		return;
>  
> -	if (is_zone_device_page(page) && !is_device_private_page(page))
> +	if (is_zone_device_page(page) &&
> +	    !is_dev_private_or_coherent_page(page))
>  		return;
>  
>  	/*
> 

Re: [PATCH v5 01/10] mm: add zone device coherent type memory support

[Alistair Popple]

Looks good, feel free to add:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Saturday, 29 January 2022 7:08:16 AM AEDT Alex Sierra wrote:
> Device memory that is cache coherent from device and CPU point of view.
> This is used on platforms that have an advanced system bus (like CAPI
> or CXL). Any page of a process can be migrated to such memory. However,
> no one should be allowed to pin such memory so that it can always be
> evicted.
> 
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
> ---
> v4:
> - use the same system entry path for coherent device pages at
> migrate_vma_insert_page.
> 
> - Add coherent device type support for try_to_migrate /
> try_to_migrate_one.
> ---
>  include/linux/memremap.h |  8 +++++++
>  include/linux/mm.h       | 16 ++++++++++++++
>  mm/memcontrol.c          |  6 +++---
>  mm/memory-failure.c      |  8 +++++--
>  mm/memremap.c            | 14 ++++++++++++-
>  mm/migrate.c             | 45 ++++++++++++++++++++--------------------
>  mm/rmap.c                |  5 +++--
>  7 files changed, 71 insertions(+), 31 deletions(-)
> 
> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
> index 1fafcc38acba..727b8c789193 100644
> --- a/include/linux/memremap.h
> +++ b/include/linux/memremap.h
> @@ -39,6 +39,13 @@ struct vmem_altmap {
>   * A more complete discussion of unaddressable memory may be found in
>   * include/linux/hmm.h and Documentation/vm/hmm.rst.
>   *
> + * MEMORY_DEVICE_COHERENT:
> + * Device memory that is cache coherent from device and CPU point of view. This
> + * is used on platforms that have an advanced system bus (like CAPI or CXL). A
> + * driver can hotplug the device memory using ZONE_DEVICE and with that memory
> + * type. Any page of a process can be migrated to such memory. However no one
> + * should be allowed to pin such memory so that it can always be evicted.
> + *
>   * MEMORY_DEVICE_FS_DAX:
>   * Host memory that has similar access semantics as System RAM i.e. DMA
>   * coherent and supports page pinning. In support of coordinating page
> @@ -59,6 +66,7 @@ struct vmem_altmap {
>  enum memory_type {
>  	/* 0 is reserved to catch uninitialized type fields */
>  	MEMORY_DEVICE_PRIVATE = 1,
> +	MEMORY_DEVICE_COHERENT,
>  	MEMORY_DEVICE_FS_DAX,
>  	MEMORY_DEVICE_GENERIC,
>  	MEMORY_DEVICE_PCI_P2PDMA,
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index e1a84b1e6787..0c61bf40edef 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1106,6 +1106,7 @@ static inline bool page_is_devmap_managed(struct page *page)
>  		return false;
>  	switch (page->pgmap->type) {
>  	case MEMORY_DEVICE_PRIVATE:
> +	case MEMORY_DEVICE_COHERENT:
>  	case MEMORY_DEVICE_FS_DAX:
>  		return true;
>  	default:
> @@ -1135,6 +1136,21 @@ static inline bool is_device_private_page(const struct page *page)
>  		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
>  }
>  
> +static inline bool is_device_coherent_page(const struct page *page)
> +{
> +	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> +		is_zone_device_page(page) &&
> +		page->pgmap->type == MEMORY_DEVICE_COHERENT;
> +}
> +
> +static inline bool is_dev_private_or_coherent_page(const struct page *page)
> +{
> +	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> +		is_zone_device_page(page) &&
> +		(page->pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +		page->pgmap->type == MEMORY_DEVICE_COHERENT);
> +}
> +
>  static inline bool is_pci_p2pdma_page(const struct page *page)
>  {
>  	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 09d342c7cbd0..0882b5b2a857 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5691,8 +5691,8 @@ static int mem_cgroup_move_account(struct page *page,
>   *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
>   *     target for charge migration. if @target is not NULL, the entry is stored
>   *     in target->ent.
> - *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is MEMORY_DEVICE_PRIVATE
> - *     (so ZONE_DEVICE page and thus not on the lru).
> + *   3(MC_TARGET_DEVICE): like MC_TARGET_PAGE  but page is device memory and
> + *   thus not on the lru.
>   *     For now we such page is charge like a regular page would be as for all
>   *     intent and purposes it is just special memory taking the place of a
>   *     regular page.
> @@ -5726,7 +5726,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
>  		 */
>  		if (page_memcg(page) == mc.from) {
>  			ret = MC_TARGET_PAGE;
> -			if (is_device_private_page(page))
> +			if (is_dev_private_or_coherent_page(page))
>  				ret = MC_TARGET_DEVICE;
>  			if (target)
>  				target->page = page;
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 14ae5c18e776..e83740f7f05e 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1611,12 +1611,16 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
>  		goto unlock;
>  	}
>  
> -	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
> +	switch (pgmap->type) {
> +	case MEMORY_DEVICE_PRIVATE:
> +	case MEMORY_DEVICE_COHERENT:
>  		/*
> -		 * TODO: Handle HMM pages which may need coordination
> +		 * TODO: Handle device pages which may need coordination
>  		 * with device-side memory.
>  		 */
>  		goto unlock;
> +	default:
> +		break;
>  	}
>  
>  	/*
> diff --git a/mm/memremap.c b/mm/memremap.c
> index 6aa5f0c2d11f..354c8027823f 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -44,6 +44,7 @@ EXPORT_SYMBOL(devmap_managed_key);
>  static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
>  {
>  	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +	    pgmap->type == MEMORY_DEVICE_COHERENT ||
>  	    pgmap->type == MEMORY_DEVICE_FS_DAX)
>  		static_branch_dec(&devmap_managed_key);
>  }
> @@ -51,6 +52,7 @@ static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
>  static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
>  {
>  	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
> +	    pgmap->type == MEMORY_DEVICE_COHERENT ||
>  	    pgmap->type == MEMORY_DEVICE_FS_DAX)
>  		static_branch_inc(&devmap_managed_key);
>  }
> @@ -327,6 +329,16 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
>  			return ERR_PTR(-EINVAL);
>  		}
>  		break;
> +	case MEMORY_DEVICE_COHERENT:
> +		if (!pgmap->ops->page_free) {
> +			WARN(1, "Missing page_free method\n");
> +			return ERR_PTR(-EINVAL);
> +		}
> +		if (!pgmap->owner) {
> +			WARN(1, "Missing owner\n");
> +			return ERR_PTR(-EINVAL);
> +		}
> +		break;
>  	case MEMORY_DEVICE_FS_DAX:
>  		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
>  		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
> @@ -469,7 +481,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
>  void free_devmap_managed_page(struct page *page)
>  {
>  	/* notify page idle for dax */
> -	if (!is_device_private_page(page)) {
> +	if (!is_dev_private_or_coherent_page(page)) {
>  		wake_up_var(&page->_refcount);
>  		return;
>  	}
> diff --git a/mm/migrate.c b/mm/migrate.c
> index c7da064b4781..cd137aedcfe5 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -345,7 +345,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
>  	 * Device private pages have an extra refcount as they are
>  	 * ZONE_DEVICE pages.
>  	 */
> -	expected_count += is_device_private_page(page);
> +	expected_count += is_dev_private_or_coherent_page(page);
>  	if (mapping)
>  		expected_count += compound_nr(page) + page_has_private(page);
>  
> @@ -2611,7 +2611,7 @@ EXPORT_SYMBOL(migrate_vma_setup);
>   *     handle_pte_fault()
>   *       do_anonymous_page()
>   * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
> - * private page.
> + * private or coherent page.
>   */
>  static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  				    unsigned long addr,
> @@ -2676,25 +2676,24 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  	 */
>  	__SetPageUptodate(page);
>  
> -	if (is_zone_device_page(page)) {
> -		if (is_device_private_page(page)) {
> -			swp_entry_t swp_entry;
> +	if (is_device_private_page(page)) {
> +		swp_entry_t swp_entry;
>  
> -			if (vma->vm_flags & VM_WRITE)
> -				swp_entry = make_writable_device_private_entry(
> -							page_to_pfn(page));
> -			else
> -				swp_entry = make_readable_device_private_entry(
> -							page_to_pfn(page));
> -			entry = swp_entry_to_pte(swp_entry);
> -		} else {
> -			/*
> -			 * For now we only support migrating to un-addressable
> -			 * device memory.
> -			 */
> -			pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
> -			goto abort;
> -		}
> +		if (vma->vm_flags & VM_WRITE)
> +			swp_entry = make_writable_device_private_entry(
> +						page_to_pfn(page));
> +		else
> +			swp_entry = make_readable_device_private_entry(
> +						page_to_pfn(page));
> +		entry = swp_entry_to_pte(swp_entry);
> +	} else if (is_zone_device_page(page) &&
> +		   !is_device_coherent_page(page)) {
> +		/*
> +		 * We support migrating to private and coherent types
> +		 * for device zone memory.
> +		 */
> +		pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
> +		goto abort;
>  	} else {
>  		entry = mk_pte(page, vma->vm_page_prot);
>  		if (vma->vm_flags & VM_WRITE)
> @@ -2796,10 +2795,10 @@ void migrate_vma_pages(struct migrate_vma *migrate)
>  		mapping = page_mapping(page);
>  
>  		if (is_zone_device_page(newpage)) {
> -			if (is_device_private_page(newpage)) {
> +			if (is_dev_private_or_coherent_page(newpage)) {
>  				/*
> -				 * For now only support private anonymous when
> -				 * migrating to un-addressable device memory.
> +				 * For now only support private and coherent
> +				 * anonymous when migrating to device memory.
>  				 */
>  				if (mapping) {
>  					migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 6a1e8c7f6213..f2bd5a3da72c 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1835,7 +1835,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
>  		/* Update high watermark before we lower rss */
>  		update_hiwater_rss(mm);
>  
> -		if (is_zone_device_page(page)) {
> +		if (is_device_private_page(page)) {
>  			unsigned long pfn = page_to_pfn(page);
>  			swp_entry_t entry;
>  			pte_t swp_pte;
> @@ -1976,7 +1976,8 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
>  					TTU_SYNC)))
>  		return;
>  
> -	if (is_zone_device_page(page) && !is_device_private_page(page))
> +	if (is_zone_device_page(page) &&
> +	    !is_dev_private_or_coherent_page(page))
>  		return;
>  
>  	/*
> 

Re: [PATCH v5 02/10] mm: add device coherent vma selection for memory migration

[Alistair Popple]

On Saturday, 29 January 2022 7:08:17 AM AEDT Alex Sierra wrote:

[...]

>  struct migrate_vma {
> diff --git a/mm/migrate.c b/mm/migrate.c
> index cd137aedcfe5..d3cc3589e1e8 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2264,7 +2264,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  			if (is_writable_device_private_entry(entry))
>  				mpfn |= MIGRATE_PFN_WRITE;
>  		} else {
> -			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT))
>  				goto next;
>  			pfn = pte_pfn(pte);
>  			if (is_zero_pfn(pfn)) {

Sorry, but I still don't think this is quite right.

When specifying MIGRATE_VMA_SELECT_DEVICE_COHERENT we are looking for pages to
migrate from the device back to system memory. But as currently written I think
this can also select the zero pfn when MIGRATE_VMA_SELECT_DEVICE_COHERENT is
specified. As far as I know that can never point to device memory so migration
of a zero pfn should be also be skipped in that case.

We should only migrate the zero pfn if MIGRATE_VMA_SELECT_SYSTEM is specified.

> @@ -2273,6 +2274,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  				goto next;
>  			}
>  			page = vm_normal_page(migrate->vma, addr, pte);
> +			if (page && !is_zone_device_page(page) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +				goto next;
> +			if (page && is_device_coherent_page(page) &&
> +			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> +			     page->pgmap->owner != migrate->pgmap_owner))
> +				goto next;
>  			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
>  			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
>  		}
> 

Re: [PATCH v5 02/10] mm: add device coherent vma selection for memory migration

[Alistair Popple]

On Saturday, 29 January 2022 7:08:17 AM AEDT Alex Sierra wrote:

[...]

>  struct migrate_vma {
> diff --git a/mm/migrate.c b/mm/migrate.c
> index cd137aedcfe5..d3cc3589e1e8 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2264,7 +2264,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  			if (is_writable_device_private_entry(entry))
>  				mpfn |= MIGRATE_PFN_WRITE;
>  		} else {
> -			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT))
>  				goto next;
>  			pfn = pte_pfn(pte);
>  			if (is_zero_pfn(pfn)) {

Sorry, but I still don't think this is quite right.

When specifying MIGRATE_VMA_SELECT_DEVICE_COHERENT we are looking for pages to
migrate from the device back to system memory. But as currently written I think
this can also select the zero pfn when MIGRATE_VMA_SELECT_DEVICE_COHERENT is
specified. As far as I know that can never point to device memory so migration
of a zero pfn should be also be skipped in that case.

We should only migrate the zero pfn if MIGRATE_VMA_SELECT_SYSTEM is specified.

> @@ -2273,6 +2274,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  				goto next;
>  			}
>  			page = vm_normal_page(migrate->vma, addr, pte);
> +			if (page && !is_zone_device_page(page) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +				goto next;
> +			if (page && is_device_coherent_page(page) &&
> +			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> +			     page->pgmap->owner != migrate->pgmap_owner))
> +				goto next;
>  			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
>  			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
>  		}
> 

[PATCH] mm: add device coherent vma selection for memory migration

[Alex Sierra]

This case is used to migrate pages from device memory, back to system
memory. Device coherent type memory is cache coherent from device and CPU
point of view.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v2:
condition added when migrations from device coherent pages.
---
 include/linux/migrate.h |  1 +
 mm/migrate.c            | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index db96e10eb8da..66a34eae8cb6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
 enum migrate_vma_direction {
 	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
 };
 
 struct migrate_vma {
diff --git a/mm/migrate.c b/mm/migrate.c
index cd137aedcfe5..69c6830c47c6 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2264,15 +2264,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (is_writable_device_private_entry(entry))
 				mpfn |= MIGRATE_PFN_WRITE;
 		} else {
-			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
-				goto next;
 			pfn = pte_pfn(pte);
-			if (is_zero_pfn(pfn)) {
+			if (is_zero_pfn(pfn) &&
+			    (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
 				mpfn = MIGRATE_PFN_MIGRATE;
 				migrate->cpages++;
 				goto next;
 			}
 			page = vm_normal_page(migrate->vma, addr, pte);
+			if (page && !is_zone_device_page(page) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+				goto next;
+			else if (page && is_device_coherent_page(page) &&
+			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
+			     page->pgmap->owner != migrate->pgmap_owner))
+				goto next;
 			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
 			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
 		}
-- 
2.32.0

[PATCH] mm: add device coherent vma selection for memory migration

[Alex Sierra]

This case is used to migrate pages from device memory, back to system
memory. Device coherent type memory is cache coherent from device and CPU
point of view.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v2:
condition added when migrations from device coherent pages.
---
 include/linux/migrate.h |  1 +
 mm/migrate.c            | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index db96e10eb8da..66a34eae8cb6 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
 enum migrate_vma_direction {
 	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
 };
 
 struct migrate_vma {
diff --git a/mm/migrate.c b/mm/migrate.c
index cd137aedcfe5..69c6830c47c6 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2264,15 +2264,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 			if (is_writable_device_private_entry(entry))
 				mpfn |= MIGRATE_PFN_WRITE;
 		} else {
-			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
-				goto next;
 			pfn = pte_pfn(pte);
-			if (is_zero_pfn(pfn)) {
+			if (is_zero_pfn(pfn) &&
+			    (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
 				mpfn = MIGRATE_PFN_MIGRATE;
 				migrate->cpages++;
 				goto next;
 			}
 			page = vm_normal_page(migrate->vma, addr, pte);
+			if (page && !is_zone_device_page(page) &&
+			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
+				goto next;
+			else if (page && is_device_coherent_page(page) &&
+			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
+			     page->pgmap->owner != migrate->pgmap_owner))
+				goto next;
 			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
 			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
 		}
-- 
2.32.0

Re: [PATCH] mm: add device coherent vma selection for memory migration

[Alistair Popple]

Thanks for fixing. I'm guessing Andrew will want you to resend this as part of
a new v6 series, but please add:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Tuesday, 1 February 2022 6:48:13 AM AEDT Alex Sierra wrote:
> This case is used to migrate pages from device memory, back to system
> memory. Device coherent type memory is cache coherent from device and CPU
> point of view.
> 
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
> ---
> v2:
> condition added when migrations from device coherent pages.
> ---
>  include/linux/migrate.h |  1 +
>  mm/migrate.c            | 12 +++++++++---
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index db96e10eb8da..66a34eae8cb6 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
>  enum migrate_vma_direction {
>  	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
>  	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
> +	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
>  };
>  
>  struct migrate_vma {
> diff --git a/mm/migrate.c b/mm/migrate.c
> index cd137aedcfe5..69c6830c47c6 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2264,15 +2264,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  			if (is_writable_device_private_entry(entry))
>  				mpfn |= MIGRATE_PFN_WRITE;
>  		} else {
> -			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> -				goto next;
>  			pfn = pte_pfn(pte);
> -			if (is_zero_pfn(pfn)) {
> +			if (is_zero_pfn(pfn) &&
> +			    (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
>  				mpfn = MIGRATE_PFN_MIGRATE;
>  				migrate->cpages++;
>  				goto next;
>  			}
>  			page = vm_normal_page(migrate->vma, addr, pte);
> +			if (page && !is_zone_device_page(page) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +				goto next;
> +			else if (page && is_device_coherent_page(page) &&
> +			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> +			     page->pgmap->owner != migrate->pgmap_owner))
> +				goto next;
>  			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
>  			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
>  		}
> 

Re: [PATCH] mm: add device coherent vma selection for memory migration

[Alistair Popple]

Thanks for fixing. I'm guessing Andrew will want you to resend this as part of
a new v6 series, but please add:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Tuesday, 1 February 2022 6:48:13 AM AEDT Alex Sierra wrote:
> This case is used to migrate pages from device memory, back to system
> memory. Device coherent type memory is cache coherent from device and CPU
> point of view.
> 
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
> ---
> v2:
> condition added when migrations from device coherent pages.
> ---
>  include/linux/migrate.h |  1 +
>  mm/migrate.c            | 12 +++++++++---
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index db96e10eb8da..66a34eae8cb6 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -130,6 +130,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn)
>  enum migrate_vma_direction {
>  	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
>  	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
> +	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
>  };
>  
>  struct migrate_vma {
> diff --git a/mm/migrate.c b/mm/migrate.c
> index cd137aedcfe5..69c6830c47c6 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2264,15 +2264,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>  			if (is_writable_device_private_entry(entry))
>  				mpfn |= MIGRATE_PFN_WRITE;
>  		} else {
> -			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> -				goto next;
>  			pfn = pte_pfn(pte);
> -			if (is_zero_pfn(pfn)) {
> +			if (is_zero_pfn(pfn) &&
> +			    (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {
>  				mpfn = MIGRATE_PFN_MIGRATE;
>  				migrate->cpages++;
>  				goto next;
>  			}
>  			page = vm_normal_page(migrate->vma, addr, pte);
> +			if (page && !is_zone_device_page(page) &&
> +			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
> +				goto next;
> +			else if (page && is_device_coherent_page(page) &&
> +			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||
> +			     page->pgmap->owner != migrate->pgmap_owner))
> +				goto next;
>  			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
>  			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
>  		}
> 

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

[Sierra Guiza, Alejandro (Alex)]

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);
>   }

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

[Sierra Guiza, Alejandro (Alex)]

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);
>   }

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

[Alistair Popple]

Oh sorry, I had looked at this but forgotten to add my reviewed by:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Tuesday, 1 February 2022 10:27:25 AM AEDT Sierra Guiza, Alejandro (Alex) wrote:
> 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);
> >   }
> 

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

[Alistair Popple]

Oh sorry, I had looked at this but forgotten to add my reviewed by:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

On Tuesday, 1 February 2022 10:27:25 AM AEDT Sierra Guiza, Alejandro (Alex) wrote:
> 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);
> >   }
>