Use the new MMU_NOTIFY_MIGRATE event to skip MMU invalidations of device
private memory and handle the invalidation in the driver as part of
migrating device private memory.
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
---
lib/test_hmm.c | 30 +++++++++++++++-----------
tools/testing/selftests/vm/hmm-tests.c | 18 ++++++++++++----
2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 74c6ee66ef15..9abc9ad3140f 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -214,6 +214,14 @@ static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni,
{
struct dmirror *dmirror = container_of(mni, struct dmirror, notifier);
+ /*
+ * Ignore invalidation callbacks for device private pages since
+ * the invalidation is handled as part of the migration process.
+ */
+ if (range->event == MMU_NOTIFY_MIGRATE &&
+ range->migrate_pgmap_owner == dmirror->mdevice)
+ return true;
+
if (mmu_notifier_range_blockable(range))
mutex_lock(&dmirror->mutex);
else if (!mutex_trylock(&dmirror->mutex))
@@ -702,7 +710,7 @@ static int dmirror_migrate(struct dmirror *dmirror,
args.dst = dst_pfns;
args.start = addr;
args.end = next;
- args.pgmap_owner = NULL;
+ args.pgmap_owner = dmirror->mdevice;
args.flags = MIGRATE_VMA_SELECT_SYSTEM;
ret = migrate_vma_setup(&args);
if (ret)
@@ -992,7 +1000,7 @@ static void dmirror_devmem_free(struct page *page)
}
static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
- struct dmirror_device *mdevice)
+ struct dmirror *dmirror)
{
const unsigned long *src = args->src;
unsigned long *dst = args->dst;
@@ -1014,6 +1022,7 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
continue;
lock_page(dpage);
+ xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
copy_highpage(dpage, spage);
*dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
if (*src & MIGRATE_PFN_WRITE)
@@ -1022,15 +1031,6 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
return 0;
}
-static void dmirror_devmem_fault_finalize_and_map(struct migrate_vma *args,
- struct dmirror *dmirror)
-{
- /* Invalidate the device's page table mapping. */
- mutex_lock(&dmirror->mutex);
- dmirror_do_update(dmirror, args->start, args->end);
- mutex_unlock(&dmirror->mutex);
-}
-
static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
{
struct migrate_vma args;
@@ -1060,11 +1060,15 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
if (migrate_vma_setup(&args))
return VM_FAULT_SIGBUS;
- ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror->mdevice);
+ ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
if (ret)
return ret;
migrate_vma_pages(&args);
- dmirror_devmem_fault_finalize_and_map(&args, dmirror);
+ /*
+ * No device finalize step is needed since
+ * dmirror_devmem_fault_alloc_and_copy() will have already
+ * invalidated the device page table.
+ */
migrate_vma_finalize(&args);
return 0;
}
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index b533dd08da1d..91d38a29956b 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -881,8 +881,9 @@ TEST_F(hmm, migrate)
}
/*
- * Migrate anonymous memory to device private memory and fault it back to system
- * memory.
+ * 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
+ * private memory to the device.
*/
TEST_F(hmm, migrate_fault)
{
@@ -924,8 +925,17 @@ TEST_F(hmm, migrate_fault)
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. */
- for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ /* Fault half the pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / (2 * sizeof(*ptr)); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Migrate memory to the device again. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_MIGRATE, 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);
--
2.20.1
