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Message-ID: <20250814072045.3637192-6-mpenttil@redhat.com>
Date: Thu, 14 Aug 2025 10:19:29 +0300
From: Mika Penttilä <mpenttil@...hat.com>
To: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org,
Mika Penttilä <mpenttil@...hat.com>,
David Hildenbrand <david@...hat.com>,
Jason Gunthorpe <jgg@...dia.com>,
Leon Romanovsky <leonro@...dia.com>,
Alistair Popple <apopple@...dia.com>,
Balbir Singh <balbirs@...dia.com>,
Marco Pagani <marpagan@...hat.com>
Subject: [RFC PATCH 4/4] mm: add new testcase for the migrate on fault case
Cc: David Hildenbrand <david@...hat.com>
Cc: Jason Gunthorpe <jgg@...dia.com>
Cc: Leon Romanovsky <leonro@...dia.com>
Cc: Alistair Popple <apopple@...dia.com>
Cc: Balbir Singh <balbirs@...dia.com>
Signed-off-by: Marco Pagani <marpagan@...hat.com>
Signed-off-by: Mika Penttilä <mpenttil@...hat.com>
---
lib/test_hmm.c | 100 ++++++++++++++++++++++++-
lib/test_hmm_uapi.h | 17 +++--
tools/testing/selftests/mm/hmm-tests.c | 53 +++++++++++++
3 files changed, 161 insertions(+), 9 deletions(-)
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index cd5c139213be..e69a5c87e414 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -36,6 +36,7 @@
#define DMIRROR_RANGE_FAULT_TIMEOUT 1000
#define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U)
#define DEVMEM_CHUNKS_RESERVE 16
+#define PFNS_ARRAY_SIZE 64
/*
* For device_private pages, dpage is just a dummy struct page
@@ -143,7 +144,7 @@ static bool dmirror_is_private_zone(struct dmirror_device *mdevice)
HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ? true : false;
}
-static enum migrate_vma_direction
+static enum migrate_vma_info
dmirror_select_device(struct dmirror *dmirror)
{
return (dmirror->mdevice->zone_device_type ==
@@ -1016,6 +1017,99 @@ static int dmirror_migrate_to_device(struct dmirror *dmirror,
return ret;
}
+static int do_fault_and_migrate(struct dmirror *dmirror, struct hmm_range *range)
+{
+ struct migrate_vma *migrate = range->migrate;
+ int ret;
+
+ mmap_read_lock(dmirror->notifier.mm);
+
+ /* Fault-in pages for migration and update device page table */
+ ret = dmirror_range_fault(dmirror, range);
+
+ pr_debug("Migrating from sys mem to device mem\n");
+ migrate_hmm_range_setup(range);
+
+ dmirror_migrate_alloc_and_copy(migrate, dmirror);
+ migrate_vma_pages(migrate);
+ dmirror_migrate_finalize_and_map(migrate, dmirror);
+ migrate_vma_finalize(migrate);
+
+ mmap_read_unlock(dmirror->notifier.mm);
+ return ret;
+}
+
+static int dmirror_fault_and_migrate_to_device(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ unsigned long start, size, end, next;
+ unsigned long src_pfns[PFNS_ARRAY_SIZE] = { 0 };
+ unsigned long dst_pfns[PFNS_ARRAY_SIZE] = { 0 };
+ struct migrate_vma migrate = { 0 };
+ struct hmm_range range = { 0 };
+ struct dmirror_bounce bounce;
+ int ret = 0;
+
+ /* Whole range */
+ start = cmd->addr;
+ size = cmd->npages << PAGE_SHIFT;
+ end = start + size;
+
+ if (!mmget_not_zero(dmirror->notifier.mm)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ migrate.pgmap_owner = dmirror->mdevice;
+ migrate.src = src_pfns;
+ migrate.dst = dst_pfns;
+
+ range.migrate = &migrate;
+ range.hmm_pfns = src_pfns;
+ range.pfn_flags_mask = 0;
+ range.default_flags = HMM_PFN_REQ_FAULT | HMM_PFN_REQ_MIGRATE;
+ range.dev_private_owner = dmirror->mdevice;
+ range.notifier = &dmirror->notifier;
+
+ for (next = start; next < end; next = range.end) {
+ range.start = next;
+ range.end = min(end, next + (PFNS_ARRAY_SIZE << PAGE_SHIFT));
+
+ pr_debug("Fault and migrate range start:%#lx end:%#lx\n",
+ range.start, range.end);
+
+ ret = do_fault_and_migrate(dmirror, &range);
+ if (ret)
+ goto out_mmput;
+ }
+
+ /*
+ * Return the migrated data for verification.
+ * Only for pages in device zone
+ ***/
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ goto out_mmput;
+
+ mutex_lock(&dmirror->mutex);
+ ret = dmirror_do_read(dmirror, start, end, &bounce);
+ mutex_unlock(&dmirror->mutex);
+ if (ret == 0) {
+ ret = copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, bounce.size);
+ if (ret)
+ ret = -EFAULT;
+ }
+
+ cmd->cpages = bounce.cpages;
+ dmirror_bounce_fini(&bounce);
+
+
+out_mmput:
+ mmput(dmirror->notifier.mm);
+out:
+ return ret;
+}
+
static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
unsigned char *perm, unsigned long entry)
{
@@ -1313,6 +1407,10 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
ret = dmirror_migrate_to_device(dmirror, &cmd);
break;
+ case HMM_DMIRROR_MIGRATE_ON_FAULT_TO_DEV:
+ ret = dmirror_fault_and_migrate_to_device(dmirror, &cmd);
+ break;
+
case HMM_DMIRROR_MIGRATE_TO_SYS:
ret = dmirror_migrate_to_system(dmirror, &cmd);
break;
diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h
index 8c818a2cf4f6..4266f0a12201 100644
--- a/lib/test_hmm_uapi.h
+++ b/lib/test_hmm_uapi.h
@@ -29,14 +29,15 @@ 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_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_RELEASE _IOWR('H', 0x07, struct hmm_dmirror_cmd)
+#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_TO_DEV _IOWR('H', 0x02, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_ON_FAULT_TO_DEV _IOWR('H', 0x03, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_MIGRATE_TO_SYS _IOWR('H', 0x04, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x05, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x06, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x07, struct hmm_dmirror_cmd)
+#define HMM_DMIRROR_RELEASE _IOWR('H', 0x08, struct hmm_dmirror_cmd)
/*
* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c
index 141bf63cbe05..059512f62d29 100644
--- a/tools/testing/selftests/mm/hmm-tests.c
+++ b/tools/testing/selftests/mm/hmm-tests.c
@@ -272,6 +272,13 @@ static int hmm_migrate_sys_to_dev(int fd,
return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_TO_DEV, buffer, npages);
}
+static int hmm_migrate_on_fault_sys_to_dev(int fd,
+ struct hmm_buffer *buffer,
+ unsigned long npages)
+{
+ return hmm_dmirror_cmd(fd, HMM_DMIRROR_MIGRATE_ON_FAULT_TO_DEV, buffer, npages);
+}
+
static int hmm_migrate_dev_to_sys(int fd,
struct hmm_buffer *buffer,
unsigned long npages)
@@ -998,6 +1005,52 @@ TEST_F(hmm, migrate)
hmm_buffer_free(buffer);
}
+/*
+ * Fault an migrate anonymous memory to device private memory.
+ */
+TEST_F(hmm, migrate_on_fault)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ buffer->ptr = mmap(NULL, size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* Initialize buffer in system memory. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Fault and migrate memory to device. */
+ ret = hmm_migrate_on_fault_sys_to_dev(self->fd, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
/*
* Migrate anonymous memory to device private memory and fault some of it back
* to system memory, then try migrating the resulting mix of system and device
--
2.50.0
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