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Subject[PATCH v6 6/6] mm/hmm/test: add self tests for HMM
Date
Add some basic stand alone self tests for HMM.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
---
MAINTAINERS | 3 +
lib/Kconfig.debug | 11 +
lib/Makefile | 1 +
lib/test_hmm.c | 1368 ++++++++++++++++++++++++
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 3 +
tools/testing/selftests/vm/config | 2 +
tools/testing/selftests/vm/hmm-tests.c | 1354 +++++++++++++++++++++++
tools/testing/selftests/vm/run_vmtests | 16 +
tools/testing/selftests/vm/test_hmm.sh | 97 ++
10 files changed, 2856 insertions(+)
create mode 100644 lib/test_hmm.c
create mode 100644 tools/testing/selftests/vm/hmm-tests.c
create mode 100755 tools/testing/selftests/vm/test_hmm.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 4017e6b760be..08508a20e2cf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7514,7 +7514,10 @@ L: linux-mm@kvack.org
S: Maintained
F: mm/hmm*
F: include/linux/hmm*
+F: include/uapi/linux/test_hmm*
F: Documentation/vm/hmm.rst
+F: lib/test_hmm*
+F: tools/testing/selftests/vm/*hmm*

HOST AP DRIVER
M: Jouni Malinen <j@w1.fi>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5ffe144c9794..d38d1e281dca 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2162,6 +2162,17 @@ config TEST_MEMINIT

If unsure, say N.

+config TEST_HMM
+ tristate "Test HMM (Heterogeneous Memory Management)"
+ depends on HMM_MIRROR
+ depends on DEVICE_PRIVATE
+ help
+ This is a pseudo device driver solely for testing HMM.
+ Say M here if you want to build the HMM test module.
+ Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
+
+ If unsure, say N.
+
endif # RUNTIME_TESTING_MENU

config MEMTEST
diff --git a/lib/Makefile b/lib/Makefile
index 93217d44237f..348ce83cb21f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
obj-$(CONFIG_TEST_STACKINIT) += test_stackinit.o
obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o
obj-$(CONFIG_TEST_MEMINIT) += test_meminit.o
+obj-$(CONFIG_TEST_HMM) += test_hmm.o

obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
new file mode 100644
index 000000000000..96ffa988969c
--- /dev/null
+++ b/lib/test_hmm.c
@@ -0,0 +1,1368 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is a module to test the HMM (Heterogeneous Memory Management)
+ * mirror and zone device private memory migration APIs of the kernel.
+ * Userspace programs can register with the driver to mirror their own address
+ * space and can use the device to read/write any valid virtual address.
+ */
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/delay.h>
+#include <linux/pagemap.h>
+#include <linux/hmm.h>
+#include <linux/vmalloc.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/sched/mm.h>
+#include <linux/platform_device.h>
+
+#include <uapi/linux/test_hmm.h>
+
+#define DMIRROR_NDEVICES 2
+#define DMIRROR_RANGE_FAULT_TIMEOUT 1000
+#define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U)
+#define DEVMEM_CHUNKS_RESERVE 16
+
+static const struct dev_pagemap_ops dmirror_devmem_ops;
+static const struct mmu_interval_notifier_ops dmirror_min_ops;
+static dev_t dmirror_dev;
+static struct page *dmirror_zero_page;
+
+struct dmirror_device;
+
+struct dmirror_bounce {
+ void *ptr;
+ unsigned long size;
+ unsigned long addr;
+ unsigned long cpages;
+};
+
+#define DPT_SHIFT PAGE_SHIFT
+#define DPT_VALID (1UL << 0)
+#define DPT_WRITE (1UL << 1)
+#define DPT_DPAGE (1UL << 2)
+
+#define DPT_XA_TAG_WRITE 3UL
+
+static const uint64_t dmirror_hmm_flags[HMM_PFN_FLAG_MAX] = {
+ [HMM_PFN_VALID] = DPT_VALID,
+ [HMM_PFN_WRITE] = DPT_WRITE,
+ [HMM_PFN_DEVICE_PRIVATE] = DPT_DPAGE,
+};
+
+static const uint64_t dmirror_hmm_values[HMM_PFN_VALUE_MAX] = {
+ [HMM_PFN_NONE] = 0,
+ [HMM_PFN_ERROR] = 0x10,
+ [HMM_PFN_SPECIAL] = 0x10,
+};
+
+/*
+ * Data structure to track address ranges and register for mmu interval
+ * notifier updates.
+ */
+struct dmirror_interval {
+ struct mmu_interval_notifier notifier;
+ struct dmirror *dmirror;
+};
+
+/*
+ * Data attached to the open device file.
+ * Note that it might be shared after a fork().
+ */
+struct dmirror {
+ struct mm_struct *mm;
+ struct dmirror_device *mdevice;
+ struct xarray pt;
+ struct mutex mutex;
+};
+
+/*
+ * ZONE_DEVICE pages for migration and simulating device memory.
+ */
+struct dmirror_chunk {
+ struct dev_pagemap pagemap;
+ struct dmirror_device *mdevice;
+};
+
+/*
+ * Per device data.
+ */
+struct dmirror_device {
+ struct cdev cdevice;
+ struct hmm_devmem *devmem;
+
+ unsigned int devmem_capacity;
+ unsigned int devmem_count;
+ struct dmirror_chunk **devmem_chunks;
+ struct mutex devmem_lock; /* protects the above */
+
+ unsigned long calloc;
+ unsigned long cfree;
+ struct page *free_pages;
+ spinlock_t lock; /* protects the above */
+};
+
+static struct dmirror_device dmirror_devices[DMIRROR_NDEVICES];
+
+static int dmirror_bounce_init(struct dmirror_bounce *bounce,
+ unsigned long addr,
+ unsigned long size)
+{
+ bounce->addr = addr;
+ bounce->size = size;
+ bounce->cpages = 0;
+ bounce->ptr = vmalloc(size);
+ if (!bounce->ptr)
+ return -ENOMEM;
+ return 0;
+}
+
+static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
+{
+ vfree(bounce->ptr);
+}
+
+static int dmirror_fops_open(struct inode *inode, struct file *filp)
+{
+ struct cdev *cdev = inode->i_cdev;
+ struct dmirror *dmirror;
+ int ret;
+
+ /* Mirror this process address space */
+ dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL);
+ if (dmirror == NULL)
+ return -ENOMEM;
+
+ dmirror->mdevice = container_of(cdev, struct dmirror_device, cdevice);
+ mutex_init(&dmirror->mutex);
+ xa_init(&dmirror->pt);
+
+ /*
+ * Pre-register for mmu interval notifiers so
+ * mmu_interval_notifier_insert_safe() can be called without holding
+ * mmap_sem for write.
+ */
+ ret = mmu_notifier_register(NULL, current->mm);
+ if (ret) {
+ kfree(dmirror);
+ return ret;
+ }
+
+ /* Pairs with the mmdrop() in dmirror_fops_release(). */
+ mmgrab(current->mm);
+ dmirror->mm = current->mm;
+
+ /* Only the first open registers the address space. */
+ filp->private_data = dmirror;
+ return ret;
+}
+
+static int dmirror_fops_release(struct inode *inode, struct file *filp)
+{
+ struct dmirror *dmirror = filp->private_data;
+ struct mmu_interval_notifier *mni;
+
+ mutex_lock(&dmirror->mutex);
+ while (true) {
+ mni = mmu_interval_notifier_find(dmirror->mm, &dmirror_min_ops,
+ 0UL, ~0UL);
+ if (!mni)
+ break;
+ mmu_interval_notifier_put(mni);
+ }
+ mutex_unlock(&dmirror->mutex);
+ mmdrop(dmirror->mm);
+ mmu_notifier_synchronize();
+ xa_destroy(&dmirror->pt);
+ kfree(dmirror);
+ return 0;
+}
+
+static inline struct dmirror_device *dmirror_page_to_device(struct page *page)
+
+{
+ struct dmirror_chunk *devmem;
+
+ devmem = container_of(page->pgmap, struct dmirror_chunk, pagemap);
+ return devmem->mdevice;
+}
+
+static bool dmirror_device_is_mine(struct dmirror_device *mdevice,
+ struct page *page)
+{
+ if (!is_zone_device_page(page))
+ return false;
+ return page->pgmap->ops == &dmirror_devmem_ops &&
+ dmirror_page_to_device(page) == mdevice;
+}
+
+static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range)
+{
+ uint64_t *pfns = range->pfns;
+ unsigned long pfn;
+
+ for (pfn = (range->start >> PAGE_SHIFT);
+ pfn < (range->end >> PAGE_SHIFT);
+ pfn++, pfns++) {
+ struct page *page;
+ void *entry;
+
+ /*
+ * HMM_PFN_ERROR is returned if it is accessing invalid memory
+ * either because of memory error (hardware detected memory
+ * corruption) or more likely because of truncate on mmap
+ * file.
+ */
+ if (*pfns == range->values[HMM_PFN_ERROR])
+ return -EFAULT;
+ if (!(*pfns & range->flags[HMM_PFN_VALID]))
+ return -EFAULT;
+ page = hmm_device_entry_to_page(range, *pfns);
+ /* We asked for pages to be populated but check anyway. */
+ if (!page)
+ return -EFAULT;
+ if (is_zone_device_page(page)) {
+ /*
+ * TODO: need a way to ask HMM to fault foreign zone
+ * device private pages.
+ */
+ if (!dmirror_device_is_mine(dmirror->mdevice, page))
+ continue;
+ }
+ entry = page;
+ if (*pfns & range->flags[HMM_PFN_WRITE])
+ entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
+ else if (range->default_flags & range->flags[HMM_PFN_WRITE])
+ return -EFAULT;
+ entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
+ if (xa_is_err(entry))
+ return xa_err(entry);
+ }
+
+ return 0;
+}
+
+static void dmirror_do_update(struct dmirror *dmirror, unsigned long start,
+ unsigned long end)
+{
+ unsigned long pfn;
+
+ /*
+ * The XArray doesn't hold references to pages since it relies on
+ * the mmu notifier to clear pointers when they become stale.
+ * Therefore, it is OK to just clear the entry.
+ */
+ for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++)
+ xa_erase(&dmirror->pt, pfn);
+}
+
+static struct dmirror_interval *dmirror_new_interval(struct dmirror *dmirror,
+ unsigned long start,
+ unsigned long last)
+{
+ struct dmirror_interval *dmi;
+ int ret;
+
+ dmi = kmalloc(sizeof(*dmi), GFP_ATOMIC);
+ if (!dmi)
+ return NULL;
+
+ dmi->dmirror = dmirror;
+
+ ret = mmu_interval_notifier_insert_safe(&dmi->notifier, dmirror->mm,
+ start, last - start + 1, &dmirror_min_ops);
+ if (ret) {
+ kfree(dmi);
+ return NULL;
+ }
+
+ return dmi;
+}
+
+static void dmirror_do_unmap(struct mmu_interval_notifier *mni,
+ const struct mmu_notifier_range *range)
+{
+ struct dmirror_interval *dmi =
+ container_of(mni, struct dmirror_interval, notifier);
+ struct dmirror *dmirror = dmi->dmirror;
+ unsigned long start = mmu_interval_notifier_start(mni);
+ unsigned long last = mmu_interval_notifier_last(mni);
+
+ if (start >= range->start) {
+ /* Remove the whole interval or keep the right-hand part. */
+ if (last <= range->end)
+ mmu_interval_notifier_put(mni);
+ else
+ mmu_interval_notifier_update(mni, range->end, last);
+ return;
+ }
+
+ /* Keep the left-hand part of the interval. */
+ mmu_interval_notifier_update(mni, start, range->start - 1);
+
+ /* If a hole is created, create an interval for the right-hand part. */
+ if (last >= range->end) {
+ dmi = dmirror_new_interval(dmirror, range->end, last);
+ /*
+ * If we can't allocate an interval, we won't get invalidation
+ * callbacks so clear the mapping and rely on faults to reload
+ * the mappings if needed.
+ */
+ if (!dmi)
+ dmirror_do_update(dmirror, range->end, last + 1);
+ }
+}
+
+static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni,
+ const struct mmu_notifier_range *range,
+ unsigned long cur_seq)
+{
+ struct dmirror_interval *dmi =
+ container_of(mni, struct dmirror_interval, notifier);
+ struct dmirror *dmirror = dmi->dmirror;
+ unsigned long start = mmu_interval_notifier_start(mni);
+ unsigned long last = mmu_interval_notifier_last(mni);
+
+ if (mmu_notifier_range_blockable(range))
+ mutex_lock(&dmirror->mutex);
+ else if (!mutex_trylock(&dmirror->mutex))
+ return false;
+
+ mmu_interval_set_seq(mni, cur_seq);
+ dmirror_do_update(dmirror, max(start, range->start),
+ min(last + 1, range->end));
+
+ /* Stop tracking the range if it is an unmap. */
+ if (range->event == MMU_NOTIFY_UNMAP)
+ dmirror_do_unmap(mni, range);
+
+ mutex_unlock(&dmirror->mutex);
+ return true;
+}
+
+static void dmirror_interval_release(struct mmu_interval_notifier *mni)
+{
+ struct dmirror_interval *dmi =
+ container_of(mni, struct dmirror_interval, notifier);
+
+ kfree(dmi);
+}
+
+static const struct mmu_interval_notifier_ops dmirror_min_ops = {
+ .invalidate = dmirror_interval_invalidate,
+ .release = dmirror_interval_release,
+};
+
+/*
+ * Find or create a mmu_interval_notifier for the given range.
+ * Although mmu_interval_notifier_insert_safe() can handle overlapping
+ * intervals, we only create non-overlapping intervals, shrinking the hmm_range
+ * if it spans more than one dmirror_interval.
+ */
+static int dmirror_interval_find(struct dmirror *dmirror,
+ struct hmm_range *range)
+{
+ struct mmu_interval_notifier *mni;
+ struct dmirror_interval *dmi;
+ struct vm_area_struct *vma;
+ unsigned long start = range->start;
+ unsigned long last = range->end - 1;
+ int ret;
+
+ mutex_lock(&dmirror->mutex);
+ mni = mmu_interval_notifier_find(dmirror->mm, &dmirror_min_ops, start,
+ last);
+ if (mni) {
+ if (start >= mmu_interval_notifier_start(mni)) {
+ dmi = container_of(mni, struct dmirror_interval,
+ notifier);
+ if (last > mmu_interval_notifier_last(mni))
+ range->end =
+ mmu_interval_notifier_last(mni) + 1;
+ goto found;
+ }
+ WARN_ON(last <= mmu_interval_notifier_start(mni));
+ range->end = mmu_interval_notifier_start(mni);
+ last = range->end - 1;
+ }
+ /*
+ * Might as well create an interval covering the underlying VMA to
+ * avoid having to create a bunch of small intervals.
+ */
+ vma = find_vma(dmirror->mm, start);
+ if (!vma || start < vma->vm_start) {
+ ret = -ENOENT;
+ goto err;
+ }
+ if (range->end > vma->vm_end) {
+ range->end = vma->vm_end;
+ last = range->end - 1;
+ } else if (!mni) {
+ /* Anything registered on the right part of the vma? */
+ mni = mmu_interval_notifier_find(dmirror->mm, &dmirror_min_ops,
+ range->end, vma->vm_end - 1);
+ if (mni)
+ last = mmu_interval_notifier_start(mni) - 1;
+ else
+ last = vma->vm_end - 1;
+ }
+ /* Anything registered on the left part of the vma? */
+ mni = mmu_interval_notifier_find(dmirror->mm, &dmirror_min_ops,
+ vma->vm_start, start - 1);
+ if (mni)
+ start = mmu_interval_notifier_last(mni) + 1;
+ else
+ start = vma->vm_start;
+ dmi = dmirror_new_interval(dmirror, start, last);
+ if (!dmi) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+found:
+ range->notifier = &dmi->notifier;
+ mutex_unlock(&dmirror->mutex);
+ return 0;
+
+err:
+ mutex_unlock(&dmirror->mutex);
+ return ret;
+}
+
+static int dmirror_range_fault(struct dmirror *dmirror,
+ struct hmm_range *range)
+{
+ struct mm_struct *mm = dmirror->mm;
+ unsigned long timeout =
+ jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+ int ret;
+
+ while (true) {
+ long count;
+
+ if (time_after(jiffies, timeout)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ down_read(&mm->mmap_sem);
+ ret = dmirror_interval_find(dmirror, range);
+ if (ret) {
+ up_read(&mm->mmap_sem);
+ goto out;
+ }
+ range->notifier_seq = mmu_interval_read_begin(range->notifier);
+ count = hmm_range_fault(range, 0);
+ up_read(&mm->mmap_sem);
+ if (count <= 0) {
+ if (count == 0 || count == -EBUSY)
+ continue;
+ ret = count;
+ goto out;
+ }
+
+ mutex_lock(&dmirror->mutex);
+ if (mmu_interval_read_retry(range->notifier,
+ range->notifier_seq)) {
+ mutex_unlock(&dmirror->mutex);
+ continue;
+ }
+ break;
+ }
+
+ ret = dmirror_do_fault(dmirror, range);
+
+ mutex_unlock(&dmirror->mutex);
+out:
+ return ret;
+}
+
+static int dmirror_fault(struct dmirror *dmirror, unsigned long start,
+ unsigned long end, bool write)
+{
+ struct mm_struct *mm = dmirror->mm;
+ unsigned long addr;
+ unsigned long next;
+ uint64_t pfns[64];
+ struct hmm_range range = {
+ .pfns = pfns,
+ .flags = dmirror_hmm_flags,
+ .values = dmirror_hmm_values,
+ .pfn_shift = DPT_SHIFT,
+ .pfn_flags_mask = ~(dmirror_hmm_flags[HMM_PFN_VALID] |
+ dmirror_hmm_flags[HMM_PFN_WRITE]),
+ .default_flags = dmirror_hmm_flags[HMM_PFN_VALID] |
+ (write ? dmirror_hmm_flags[HMM_PFN_WRITE] : 0),
+ };
+ int ret = 0;
+
+ /* Since the mm is for the mirrored process, get a reference first. */
+ if (!mmget_not_zero(mm))
+ return 0;
+
+ for (addr = start; addr < end; addr = next) {
+ next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
+ range.start = addr;
+ range.end = next;
+
+ ret = dmirror_range_fault(dmirror, &range);
+ if (ret)
+ break;
+ }
+
+ mmput(mm);
+ return ret;
+}
+
+static int dmirror_do_read(struct dmirror *dmirror, unsigned long start,
+ unsigned long end, struct dmirror_bounce *bounce)
+{
+ unsigned long pfn;
+ void *ptr;
+
+ ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK);
+
+ for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
+ void *entry;
+ struct page *page;
+ void *tmp;
+
+ entry = xa_load(&dmirror->pt, pfn);
+ page = xa_untag_pointer(entry);
+ if (!page)
+ return -ENOENT;
+
+ tmp = kmap(page);
+ memcpy(ptr, tmp, PAGE_SIZE);
+ kunmap(page);
+
+ ptr += PAGE_SIZE;
+ bounce->cpages++;
+ }
+
+ return 0;
+}
+
+static int dmirror_read(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
+{
+ struct dmirror_bounce bounce;
+ unsigned long start, end;
+ unsigned long size = cmd->npages << PAGE_SHIFT;
+ int ret;
+
+ start = cmd->addr;
+ end = start + size;
+ if (end < start)
+ return -EINVAL;
+
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ return ret;
+
+again:
+ mutex_lock(&dmirror->mutex);
+ ret = dmirror_do_read(dmirror, start, end, &bounce);
+ mutex_unlock(&dmirror->mutex);
+ if (ret == 0)
+ ret = copy_to_user((void __user *)cmd->ptr, bounce.ptr,
+ bounce.size);
+ else if (ret == -ENOENT) {
+ start = cmd->addr + (bounce.cpages << PAGE_SHIFT);
+ ret = dmirror_fault(dmirror, start, end, false);
+ if (ret == 0) {
+ cmd->faults++;
+ goto again;
+ }
+ }
+
+ cmd->cpages = bounce.cpages;
+ dmirror_bounce_fini(&bounce);
+ return ret;
+}
+
+static int dmirror_do_write(struct dmirror *dmirror, unsigned long start,
+ unsigned long end, struct dmirror_bounce *bounce)
+{
+ unsigned long pfn;
+ void *ptr;
+
+ ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK);
+
+ for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
+ void *entry;
+ struct page *page;
+ void *tmp;
+
+ entry = xa_load(&dmirror->pt, pfn);
+ page = xa_untag_pointer(entry);
+ if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE)
+ return -ENOENT;
+
+ tmp = kmap(page);
+ memcpy(tmp, ptr, PAGE_SIZE);
+ kunmap(page);
+
+ ptr += PAGE_SIZE;
+ bounce->cpages++;
+ }
+
+ return 0;
+}
+
+static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
+{
+ struct dmirror_bounce bounce;
+ unsigned long start, end;
+ unsigned long size = cmd->npages << PAGE_SHIFT;
+ int ret;
+
+ start = cmd->addr;
+ end = start + size;
+ if (end < start)
+ return -EINVAL;
+
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ return ret;
+ ret = copy_from_user(bounce.ptr, (void __user *)cmd->ptr,
+ bounce.size);
+ if (ret)
+ return ret;
+
+again:
+ mutex_lock(&dmirror->mutex);
+ ret = dmirror_do_write(dmirror, start, end, &bounce);
+ mutex_unlock(&dmirror->mutex);
+ if (ret == -ENOENT) {
+ start = cmd->addr + (bounce.cpages << PAGE_SHIFT);
+ ret = dmirror_fault(dmirror, start, end, true);
+ if (ret == 0) {
+ cmd->faults++;
+ goto again;
+ }
+ }
+
+ cmd->cpages = bounce.cpages;
+ dmirror_bounce_fini(&bounce);
+ return ret;
+}
+
+static bool dmirror_allocate_chunk(struct dmirror_device *mdevice,
+ struct page **ppage)
+{
+ struct dmirror_chunk *devmem;
+ struct resource *res;
+ unsigned long pfn;
+ unsigned long pfn_first;
+ unsigned long pfn_last;
+ void *ptr;
+
+ mutex_lock(&mdevice->devmem_lock);
+
+ if (mdevice->devmem_count == mdevice->devmem_capacity) {
+ struct dmirror_chunk **new_chunks;
+ unsigned int new_capacity;
+
+ new_capacity = mdevice->devmem_capacity +
+ DEVMEM_CHUNKS_RESERVE;
+ new_chunks = krealloc(mdevice->devmem_chunks,
+ sizeof(new_chunks[0]) * new_capacity,
+ GFP_KERNEL);
+ if (!new_chunks)
+ goto err;
+ mdevice->devmem_capacity = new_capacity;
+ mdevice->devmem_chunks = new_chunks;
+ }
+
+ res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
+ "hmm_dmirror");
+ if (IS_ERR(res))
+ goto err;
+
+ devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
+ if (!devmem)
+ goto err;
+
+ devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+ devmem->pagemap.res = *res;
+ devmem->pagemap.ops = &dmirror_devmem_ops;
+
+ ptr = memremap_pages(&devmem->pagemap, numa_node_id());
+ if (IS_ERR(ptr))
+ goto err_free;
+
+ devmem->mdevice = mdevice;
+ pfn_first = devmem->pagemap.res.start >> PAGE_SHIFT;
+ pfn_last = pfn_first +
+ (resource_size(&devmem->pagemap.res) >> PAGE_SHIFT);
+ mdevice->devmem_chunks[mdevice->devmem_count++] = devmem;
+
+ mutex_unlock(&mdevice->devmem_lock);
+
+ pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n",
+ DEVMEM_CHUNK_SIZE / (1024 * 1024),
+ mdevice->devmem_count,
+ mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)),
+ pfn_first, pfn_last);
+
+ spin_lock(&mdevice->lock);
+ for (pfn = pfn_first; pfn < pfn_last; pfn++) {
+ struct page *page = pfn_to_page(pfn);
+
+ page->zone_device_data = mdevice->free_pages;
+ mdevice->free_pages = page;
+ }
+ if (ppage) {
+ *ppage = mdevice->free_pages;
+ mdevice->free_pages = (*ppage)->zone_device_data;
+ mdevice->calloc++;
+ }
+ spin_unlock(&mdevice->lock);
+
+ return true;
+
+err_free:
+ kfree(devmem);
+err:
+ mutex_unlock(&mdevice->devmem_lock);
+ return false;
+}
+
+static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
+{
+ struct page *dpage = NULL;
+ struct page *rpage;
+
+ /*
+ * This is a fake device so we alloc real system memory to store
+ * our device memory.
+ */
+ rpage = alloc_page(GFP_HIGHUSER);
+ if (!rpage)
+ return NULL;
+
+ spin_lock(&mdevice->lock);
+
+ if (mdevice->free_pages) {
+ dpage = mdevice->free_pages;
+ mdevice->free_pages = dpage->zone_device_data;
+ mdevice->calloc++;
+ spin_unlock(&mdevice->lock);
+ } else {
+ spin_unlock(&mdevice->lock);
+ if (!dmirror_allocate_chunk(mdevice, &dpage))
+ goto error;
+ }
+
+ dpage->zone_device_data = rpage;
+ get_page(dpage);
+ lock_page(dpage);
+ return dpage;
+
+error:
+ __free_page(rpage);
+ return NULL;
+}
+
+static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
+ struct dmirror *dmirror)
+{
+ struct dmirror_device *mdevice = dmirror->mdevice;
+ const unsigned long *src = args->src;
+ unsigned long *dst = args->dst;
+ unsigned long addr;
+
+ for (addr = args->start; addr < args->end; addr += PAGE_SIZE,
+ src++, dst++) {
+ struct page *spage;
+ struct page *dpage;
+ struct page *rpage;
+
+ if (!(*src & MIGRATE_PFN_MIGRATE))
+ continue;
+
+ /*
+ * Note that spage might be NULL which is OK since it is an
+ * unallocated pte_none() or read-only zero page.
+ */
+ spage = migrate_pfn_to_page(*src);
+
+ /*
+ * Don't migrate device private pages from our own driver or
+ * others. For our own we would do a device private memory copy
+ * not a migration and for others, we would need to fault the
+ * other device's page into system memory first.
+ */
+ if (spage && is_zone_device_page(spage))
+ continue;
+
+ dpage = dmirror_devmem_alloc_page(mdevice);
+ if (!dpage)
+ continue;
+
+ rpage = dpage->zone_device_data;
+ if (spage)
+ copy_highpage(rpage, spage);
+ else
+ clear_highpage(rpage);
+
+ /*
+ * Normally, a device would use the page->zone_device_data to
+ * point to the mirror but here we use it to hold the page for
+ * the simulated device memory and that page holds the pointer
+ * to the mirror.
+ */
+ rpage->zone_device_data = dmirror;
+
+ *dst = migrate_pfn(page_to_pfn(dpage)) |
+ MIGRATE_PFN_LOCKED;
+ if ((*src & MIGRATE_PFN_WRITE) ||
+ (!spage && args->vma->vm_flags & VM_WRITE))
+ *dst |= MIGRATE_PFN_WRITE;
+ }
+}
+
+static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
+ struct dmirror *dmirror)
+{
+ unsigned long start = args->start;
+ unsigned long end = args->end;
+ const unsigned long *src = args->src;
+ const unsigned long *dst = args->dst;
+ unsigned long pfn;
+
+ /* Map the migrated pages into the device's page tables. */
+ mutex_lock(&dmirror->mutex);
+
+ for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++,
+ src++, dst++) {
+ struct page *dpage;
+ void *entry;
+
+ if (!(*src & MIGRATE_PFN_MIGRATE))
+ continue;
+
+ dpage = migrate_pfn_to_page(*dst);
+ 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;
+ if (*dst & MIGRATE_PFN_WRITE)
+ entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
+ entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
+ if (xa_is_err(entry))
+ return xa_err(entry);
+ }
+
+ mutex_unlock(&dmirror->mutex);
+ return 0;
+}
+
+static int dmirror_migrate(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->mm;
+ struct vm_area_struct *vma;
+ unsigned long src_pfns[64];
+ unsigned long dst_pfns[64];
+ struct dmirror_bounce bounce;
+ 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;
+
+ down_read(&mm->mmap_sem);
+ for (addr = start; addr < end; addr = next) {
+ vma = find_vma(mm, addr);
+ if (!vma || addr < vma->vm_start) {
+ 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;
+ ret = migrate_vma_setup(&args);
+ if (ret)
+ goto out;
+
+ dmirror_migrate_alloc_and_copy(&args, dmirror);
+ migrate_vma_pages(&args);
+ dmirror_migrate_finalize_and_map(&args, dmirror);
+ migrate_vma_finalize(&args);
+ }
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+
+ /* Return the migrated data for verification. */
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ return ret;
+ mutex_lock(&dmirror->mutex);
+ ret = dmirror_do_read(dmirror, start, end, &bounce);
+ mutex_unlock(&dmirror->mutex);
+ if (ret == 0)
+ ret = copy_to_user((void __user *)cmd->ptr, bounce.ptr,
+ bounce.size);
+ cmd->cpages = bounce.cpages;
+ dmirror_bounce_fini(&bounce);
+ return ret;
+
+out:
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+ return ret;
+}
+
+static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
+ unsigned char *perm, uint64_t entry)
+{
+ struct page *page;
+
+ if (entry == range->values[HMM_PFN_ERROR]) {
+ *perm = HMM_DMIRROR_PROT_ERROR;
+ return;
+ }
+ page = hmm_device_entry_to_page(range, entry);
+ if (!page) {
+ *perm = HMM_DMIRROR_PROT_NONE;
+ return;
+ }
+ if (entry & range->flags[HMM_PFN_DEVICE_PRIVATE]) {
+ /* Is the page migrated to this device or some other? */
+ if (dmirror->mdevice == dmirror_page_to_device(page))
+ *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
+ else
+ *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
+ } else if (is_zero_pfn(page_to_pfn(page)))
+ *perm = HMM_DMIRROR_PROT_ZERO;
+ else
+ *perm = HMM_DMIRROR_PROT_NONE;
+ if (entry & range->flags[HMM_PFN_WRITE])
+ *perm |= HMM_DMIRROR_PROT_WRITE;
+ else
+ *perm |= HMM_DMIRROR_PROT_READ;
+}
+
+static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni,
+ const struct mmu_notifier_range *range,
+ unsigned long cur_seq)
+{
+ struct dmirror_interval *dmi =
+ container_of(mni, struct dmirror_interval, notifier);
+ struct dmirror *dmirror = dmi->dmirror;
+
+ if (mmu_notifier_range_blockable(range))
+ mutex_lock(&dmirror->mutex);
+ else if (!mutex_trylock(&dmirror->mutex))
+ return false;
+
+ /*
+ * Snapshots only need to set the sequence number since the
+ * invalidations are handled by the dmirror_interval ranges.
+ */
+ mmu_interval_set_seq(mni, cur_seq);
+
+ mutex_unlock(&dmirror->mutex);
+ return true;
+}
+
+static const struct mmu_interval_notifier_ops dmirror_mrn_ops = {
+ .invalidate = dmirror_snapshot_invalidate,
+};
+
+static int dmirror_range_snapshot(struct dmirror *dmirror,
+ struct hmm_range *range,
+ unsigned char *perm)
+{
+ struct mm_struct *mm = dmirror->mm;
+ struct dmirror_interval notifier;
+ unsigned long timeout =
+ jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+ unsigned long i;
+ unsigned long n;
+ int ret = 0;
+
+ notifier.dmirror = dmirror;
+ range->notifier = &notifier.notifier;
+
+ ret = mmu_interval_notifier_insert_safe(range->notifier, mm,
+ range->start, range->end - range->start,
+ &dmirror_mrn_ops);
+ if (ret)
+ return ret;
+
+ while (true) {
+ long count;
+
+ if (time_after(jiffies, timeout)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ range->notifier_seq = mmu_interval_read_begin(range->notifier);
+
+ down_read(&mm->mmap_sem);
+ count = hmm_range_fault(range, HMM_FAULT_SNAPSHOT);
+ up_read(&mm->mmap_sem);
+ if (count <= 0) {
+ if (count == 0 || count == -EBUSY)
+ continue;
+ ret = count;
+ goto out;
+ }
+
+ mutex_lock(&dmirror->mutex);
+ if (mmu_interval_read_retry(range->notifier,
+ range->notifier_seq)) {
+ mutex_unlock(&dmirror->mutex);
+ continue;
+ }
+ break;
+ }
+
+ n = (range->end - range->start) >> PAGE_SHIFT;
+ for (i = 0; i < n; i++)
+ dmirror_mkentry(dmirror, range, perm + i, range->pfns[i]);
+
+ mutex_unlock(&dmirror->mutex);
+out:
+ mmu_interval_notifier_remove(range->notifier);
+ return ret;
+}
+
+static int dmirror_snapshot(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ struct mm_struct *mm = dmirror->mm;
+ unsigned long start, end;
+ unsigned long size = cmd->npages << PAGE_SHIFT;
+ unsigned long addr;
+ unsigned long next;
+ uint64_t pfns[64];
+ unsigned char perm[64];
+ char __user *uptr;
+ struct hmm_range range = {
+ .pfns = pfns,
+ .flags = dmirror_hmm_flags,
+ .values = dmirror_hmm_values,
+ .pfn_shift = DPT_SHIFT,
+ .pfn_flags_mask = ~0ULL,
+ };
+ int ret = 0;
+
+ 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;
+
+ /*
+ * Register a temporary notifier to detect invalidations even if it
+ * overlaps with other mmu_interval_notifiers.
+ */
+ uptr = (void __user *)cmd->ptr;
+ for (addr = start; addr < end; addr = next) {
+ unsigned long n;
+
+ next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
+ range.start = addr;
+ range.end = next;
+
+ ret = dmirror_range_snapshot(dmirror, &range, perm);
+ if (ret)
+ break;
+
+ n = (range.end - range.start) >> PAGE_SHIFT;
+ ret = copy_to_user(uptr, perm, n);
+ if (ret)
+ break;
+
+ cmd->cpages += n;
+ uptr += n;
+ }
+ mmput(mm);
+
+ return ret;
+}
+
+static long dmirror_fops_unlocked_ioctl(struct file *filp,
+ unsigned int command,
+ unsigned long arg)
+{
+ void __user *uarg = (void __user *)arg;
+ struct hmm_dmirror_cmd cmd;
+ struct dmirror *dmirror;
+ int ret;
+
+ dmirror = filp->private_data;
+ if (!dmirror)
+ return -EINVAL;
+
+ ret = copy_from_user(&cmd, uarg, sizeof(cmd));
+ if (ret)
+ return ret;
+
+ if (cmd.addr & ~PAGE_MASK)
+ return -EINVAL;
+ if (cmd.addr >= (cmd.addr + (cmd.npages << PAGE_SHIFT)))
+ return -EINVAL;
+
+ cmd.cpages = 0;
+ cmd.faults = 0;
+
+ switch (command) {
+ case HMM_DMIRROR_READ:
+ ret = dmirror_read(dmirror, &cmd);
+ break;
+
+ case HMM_DMIRROR_WRITE:
+ ret = dmirror_write(dmirror, &cmd);
+ break;
+
+ case HMM_DMIRROR_MIGRATE:
+ ret = dmirror_migrate(dmirror, &cmd);
+ break;
+
+ case HMM_DMIRROR_SNAPSHOT:
+ ret = dmirror_snapshot(dmirror, &cmd);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ if (ret)
+ return ret;
+
+ return copy_to_user(uarg, &cmd, sizeof(cmd));
+}
+
+static const struct file_operations dmirror_fops = {
+ .open = dmirror_fops_open,
+ .release = dmirror_fops_release,
+ .unlocked_ioctl = dmirror_fops_unlocked_ioctl,
+ .llseek = default_llseek,
+ .owner = THIS_MODULE,
+};
+
+static void dmirror_devmem_free(struct page *page)
+{
+ struct page *rpage = page->zone_device_data;
+ struct dmirror_device *mdevice;
+
+ if (rpage)
+ __free_page(rpage);
+
+ mdevice = dmirror_page_to_device(page);
+
+ spin_lock(&mdevice->lock);
+ mdevice->cfree++;
+ page->zone_device_data = mdevice->free_pages;
+ mdevice->free_pages = page;
+ spin_unlock(&mdevice->lock);
+}
+
+static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
+ struct dmirror_device *mdevice)
+{
+ struct vm_area_struct *vma = args->vma;
+ 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 (!dmirror_device_is_mine(mdevice, spage))
+ continue;
+ spage = spage->zone_device_data;
+
+ dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr);
+ if (!dpage)
+ continue;
+
+ lock_page(dpage);
+ copy_highpage(dpage, spage);
+ *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
+ if (*src & MIGRATE_PFN_WRITE)
+ *dst |= MIGRATE_PFN_WRITE;
+ }
+ 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;
+ unsigned long src_pfns;
+ unsigned long dst_pfns;
+ struct page *rpage;
+ struct dmirror *dmirror;
+ vm_fault_t ret;
+
+ /* FIXME demonstrate how we can adjust migrate range */
+ args.vma = vmf->vma;
+ args.start = vmf->address;
+ args.end = args.start + PAGE_SIZE;
+ args.src = &src_pfns;
+ args.dst = &dst_pfns;
+
+ if (migrate_vma_setup(&args))
+ return VM_FAULT_SIGBUS;
+
+ /*
+ * Normally, a device would use the page->zone_device_data to point to
+ * the mirror but here we use it to hold the page for the simulated
+ * device memory and that page holds the pointer to the mirror.
+ */
+ rpage = vmf->page->zone_device_data;
+ dmirror = rpage->zone_device_data;
+
+ ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror->mdevice);
+ if (ret)
+ return ret;
+ migrate_vma_pages(&args);
+ dmirror_devmem_fault_finalize_and_map(&args, dmirror);
+ migrate_vma_finalize(&args);
+ return 0;
+}
+
+static const struct dev_pagemap_ops dmirror_devmem_ops = {
+ .page_free = dmirror_devmem_free,
+ .migrate_to_ram = dmirror_devmem_fault,
+};
+
+static int dmirror_device_init(struct dmirror_device *mdevice, int id)
+{
+ dev_t dev;
+ int ret;
+
+ dev = MKDEV(MAJOR(dmirror_dev), id);
+ mutex_init(&mdevice->devmem_lock);
+ spin_lock_init(&mdevice->lock);
+
+ cdev_init(&mdevice->cdevice, &dmirror_fops);
+ ret = cdev_add(&mdevice->cdevice, dev, 1);
+ if (ret)
+ return ret;
+
+ /* Build a list of free ZONE_DEVICE private struct pages */
+ dmirror_allocate_chunk(mdevice, NULL);
+
+ return 0;
+}
+
+static void dmirror_device_remove(struct dmirror_device *mdevice)
+{
+ unsigned int i;
+
+ if (mdevice->devmem_chunks) {
+ for (i = 0; i < mdevice->devmem_count; i++) {
+ struct dmirror_chunk *devmem =
+ mdevice->devmem_chunks[i];
+
+ memunmap_pages(&devmem->pagemap);
+ kfree(devmem);
+ }
+ kfree(mdevice->devmem_chunks);
+ }
+
+ cdev_del(&mdevice->cdevice);
+}
+
+static int __init hmm_dmirror_init(void)
+{
+ int ret;
+ int id;
+
+ ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
+ "HMM_DMIRROR");
+ if (ret)
+ goto err_unreg;
+
+ for (id = 0; id < DMIRROR_NDEVICES; id++) {
+ ret = dmirror_device_init(dmirror_devices + id, id);
+ if (ret)
+ goto err_chrdev;
+ }
+
+ /*
+ * Allocate a zero page to simulate a reserved page of device private
+ * memory which is always zero. The zero_pfn page isn't used just to
+ * make the code here simpler (i.e., we need a struct page for it).
+ */
+ dmirror_zero_page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
+ if (!dmirror_zero_page)
+ goto err_chrdev;
+
+ pr_info("HMM test module loaded. This is only for testing HMM.\n");
+ return 0;
+
+err_chrdev:
+ while (--id >= 0)
+ dmirror_device_remove(dmirror_devices + id);
+ unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
+err_unreg:
+ return ret;
+}
+
+static void __exit hmm_dmirror_exit(void)
+{
+ int id;
+
+ if (dmirror_zero_page)
+ __free_page(dmirror_zero_page);
+ for (id = 0; id < DMIRROR_NDEVICES; id++)
+ dmirror_device_remove(dmirror_devices + id);
+ unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
+}
+
+module_init(hmm_dmirror_init);
+module_exit(hmm_dmirror_exit);
+MODULE_LICENSE("GPL");
diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore
index 31b3c98b6d34..3054565b3f07 100644
--- a/tools/testing/selftests/vm/.gitignore
+++ b/tools/testing/selftests/vm/.gitignore
@@ -14,3 +14,4 @@ virtual_address_range
gup_benchmark
va_128TBswitch
map_fixed_noreplace
+hmm-tests
diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 7f9a8a8c31da..3fadab99d991 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -7,6 +7,7 @@ CFLAGS = -Wall -I ../../../../usr/include $(EXTRA_CFLAGS)
LDLIBS = -lrt
TEST_GEN_FILES = compaction_test
TEST_GEN_FILES += gup_benchmark
+TEST_GEN_FILES += hmm-tests
TEST_GEN_FILES += hugepage-mmap
TEST_GEN_FILES += hugepage-shm
TEST_GEN_FILES += map_hugetlb
@@ -31,6 +32,8 @@ TEST_FILES := test_vmalloc.sh
KSFT_KHDR_INSTALL := 1
include ../lib.mk

+$(OUTPUT)/hmm-tests: LDLIBS += -lhugetlbfs -lpthread
+
$(OUTPUT)/userfaultfd: LDLIBS += -lpthread

$(OUTPUT)/mlock-random-test: LDLIBS += -lcap
diff --git a/tools/testing/selftests/vm/config b/tools/testing/selftests/vm/config
index 93b90a9b1eeb..f6d0adad739f 100644
--- a/tools/testing/selftests/vm/config
+++ b/tools/testing/selftests/vm/config
@@ -1,3 +1,5 @@
CONFIG_SYSVIPC=y
CONFIG_USERFAULTFD=y
CONFIG_TEST_VMALLOC=m
+CONFIG_HMM_MIRROR=y
+CONFIG_DEVICE_PRIVATE=y
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
new file mode 100644
index 000000000000..23bf2e956f1d
--- /dev/null
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -0,0 +1,1354 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * HMM stands for Heterogeneous Memory Management, it is a helper layer inside
+ * the linux kernel to help device drivers mirror a process address space in
+ * the device. This allows the device to use the same address space which
+ * makes communication and data exchange a lot easier.
+ *
+ * This framework's sole purpose is to exercise various code paths inside
+ * the kernel to make sure that HMM performs as expected and to flush out any
+ * bugs.
+ */
+
+#include "../kselftest_harness.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <strings.h>
+#include <time.h>
+#include <pthread.h>
+#include <hugetlbfs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/ioctl.h>
+#include <linux/test_hmm.h>
+
+struct hmm_buffer {
+ void *ptr;
+ void *mirror;
+ unsigned long size;
+ int fd;
+ uint64_t cpages;
+ uint64_t faults;
+};
+
+#define TWOMEG (1 << 21)
+#define HMM_BUFFER_SIZE (1024 << 12)
+#define HMM_PATH_MAX 64
+#define NTIMES 256
+
+#define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1)))
+
+FIXTURE(hmm)
+{
+ int fd;
+ unsigned int page_size;
+ unsigned int page_shift;
+};
+
+FIXTURE(hmm2)
+{
+ int fd0;
+ int fd1;
+ unsigned int page_size;
+ unsigned int page_shift;
+};
+
+static int hmm_open(int unit)
+{
+ char pathname[HMM_PATH_MAX];
+ int fd;
+
+ snprintf(pathname, sizeof(pathname), "/dev/hmm_dmirror%d", unit);
+ fd = open(pathname, O_RDWR, 0);
+ if (fd < 0)
+ fprintf(stderr, "could not open hmm dmirror driver (%s)\n",
+ pathname);
+ return fd;
+}
+
+FIXTURE_SETUP(hmm)
+{
+ self->page_size = sysconf(_SC_PAGE_SIZE);
+ self->page_shift = ffs(self->page_size) - 1;
+
+ self->fd = hmm_open(0);
+ ASSERT_GE(self->fd, 0);
+}
+
+FIXTURE_SETUP(hmm2)
+{
+ self->page_size = sysconf(_SC_PAGE_SIZE);
+ self->page_shift = ffs(self->page_size) - 1;
+
+ self->fd0 = hmm_open(0);
+ ASSERT_GE(self->fd0, 0);
+ self->fd1 = hmm_open(1);
+ ASSERT_GE(self->fd1, 0);
+}
+
+FIXTURE_TEARDOWN(hmm)
+{
+ int ret = close(self->fd);
+
+ ASSERT_EQ(ret, 0);
+ self->fd = -1;
+}
+
+FIXTURE_TEARDOWN(hmm2)
+{
+ int ret = close(self->fd0);
+
+ ASSERT_EQ(ret, 0);
+ self->fd0 = -1;
+
+ ret = close(self->fd1);
+ ASSERT_EQ(ret, 0);
+ self->fd1 = -1;
+}
+
+static int hmm_dmirror_cmd(int fd,
+ unsigned long request,
+ struct hmm_buffer *buffer,
+ unsigned long npages)
+{
+ struct hmm_dmirror_cmd cmd;
+ int ret;
+
+ /* Simulate a device reading system memory. */
+ cmd.addr = (__u64)buffer->ptr;
+ cmd.ptr = (__u64)buffer->mirror;
+ cmd.npages = npages;
+
+ for (;;) {
+ ret = ioctl(fd, request, &cmd);
+ if (ret == 0)
+ break;
+ if (errno == EINTR)
+ continue;
+ return -errno;
+ }
+ buffer->cpages = cmd.cpages;
+ buffer->faults = cmd.faults;
+
+ return 0;
+}
+
+static void hmm_buffer_free(struct hmm_buffer *buffer)
+{
+ if (buffer == NULL)
+ return;
+
+ if (buffer->ptr)
+ munmap(buffer->ptr, buffer->size);
+ free(buffer->mirror);
+ free(buffer);
+}
+
+/*
+ * Create a temporary file that will be deleted on close.
+ */
+static int hmm_create_file(unsigned long size)
+{
+ char path[HMM_PATH_MAX];
+ int fd;
+
+ strcpy(path, "/tmp");
+ fd = open(path, O_TMPFILE | O_EXCL | O_RDWR, 0600);
+ if (fd >= 0) {
+ int r;
+
+ do {
+ r = ftruncate(fd, size);
+ } while (r == -1 && errno == EINTR);
+ if (!r)
+ return fd;
+ close(fd);
+ }
+ return -1;
+}
+
+/*
+ * Return a random unsigned number.
+ */
+static unsigned int hmm_random(void)
+{
+ static int fd = -1;
+ unsigned int r;
+
+ if (fd < 0) {
+ fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr, "%s:%d failed to open /dev/urandom\n",
+ __FILE__, __LINE__);
+ return ~0U;
+ }
+ }
+ read(fd, &r, sizeof(r));
+ return r;
+}
+
+static void hmm_nanosleep(unsigned int n)
+{
+ struct timespec t;
+
+ t.tv_sec = 0;
+ t.tv_nsec = n;
+ nanosleep(&t, NULL);
+}
+
+/*
+ * Simple NULL test of device open/close.
+ */
+TEST_F(hmm, open_close)
+{
+}
+
+/*
+ * Read private anonymous memory.
+ */
+TEST_F(hmm, anon_read)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ int val;
+
+ 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 but leave the first two pages
+ * zero (pte_none and pfn_zero).
+ */
+ i = 2 * self->page_size / sizeof(*ptr);
+ for (ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Set buffer permission to read-only. */
+ ret = mprotect(buffer->ptr, size, PROT_READ);
+ ASSERT_EQ(ret, 0);
+
+ /* Populate the CPU page table with a special zero page. */
+ val = *(int *)(buffer->ptr + self->page_size);
+ ASSERT_EQ(val, 0);
+
+ /* Simulate a device reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device read. */
+ ptr = buffer->mirror;
+ for (i = 0; i < 2 * self->page_size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+ for (; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Read private anonymous memory which has been protected with
+ * mprotect() PROT_NONE.
+ */
+TEST_F(hmm, anon_read_prot)
+{
+ 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;
+
+ /* Initialize mirror buffer so we can verify it isn't written. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = -i;
+
+ /* Protect buffer from reading. */
+ ret = mprotect(buffer->ptr, size, PROT_NONE);
+ ASSERT_EQ(ret, 0);
+
+ /* Simulate a device reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, -EFAULT);
+
+ /* Allow CPU to read the buffer so we can check it. */
+ ret = mprotect(buffer->ptr, size, PROT_READ);
+ ASSERT_EQ(ret, 0);
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* 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);
+}
+
+/*
+ * Write private anonymous memory.
+ */
+TEST_F(hmm, anon_write)
+{
+ 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 data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Write private anonymous memory which has been protected with
+ * mprotect() PROT_READ.
+ */
+TEST_F(hmm, anon_write_prot)
+{
+ 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,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* Simulate a device reading a zero page of memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer, 1);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, 1);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, -EPERM);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], 0);
+
+ /* Now allow writing and see that the zero page is replaced. */
+ ret = mprotect(buffer->ptr, size, PROT_WRITE | PROT_READ);
+ ASSERT_EQ(ret, 0);
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Check that a device writing an anonymous private mapping
+ * will copy-on-write if a child process inherits the mapping.
+ */
+TEST_F(hmm, anon_write_child)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ pid_t pid;
+ int child_fd;
+ 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->ptr so we can tell if it is written. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = -i;
+
+ pid = fork();
+ if (pid == -1)
+ ASSERT_EQ(pid, 0);
+ if (pid != 0) {
+ waitpid(pid, &ret, 0);
+ ASSERT_EQ(WIFEXITED(ret), 1);
+
+ /* Check that the parent's buffer did not change. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+ return;
+ }
+
+ /* Check that we see the parent's values. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], -i);
+
+ /* The child process needs its own mirror to its own mm. */
+ child_fd = hmm_open(0);
+ ASSERT_GE(child_fd, 0);
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(child_fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], -i);
+
+ close(child_fd);
+ exit(0);
+}
+
+/*
+ * Check that a device writing an anonymous shared mapping
+ * will not copy-on-write if a child process inherits the mapping.
+ */
+TEST_F(hmm, anon_write_child_shared)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ pid_t pid;
+ int child_fd;
+ 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_SHARED | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* Initialize buffer->ptr so we can tell if it is written. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = -i;
+
+ pid = fork();
+ if (pid == -1)
+ ASSERT_EQ(pid, 0);
+ if (pid != 0) {
+ waitpid(pid, &ret, 0);
+ ASSERT_EQ(WIFEXITED(ret), 1);
+
+ /* Check that the parent's buffer did change. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], -i);
+ return;
+ }
+
+ /* Check that we see the parent's values. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], -i);
+
+ /* The child process needs its own mirror to its own mm. */
+ child_fd = hmm_open(0);
+ ASSERT_GE(child_fd, 0);
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(child_fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], -i);
+
+ close(child_fd);
+ exit(0);
+}
+
+/*
+ * Write private anonymous huge page.
+ */
+TEST_F(hmm, anon_write_huge)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ void *old_ptr;
+ void *map;
+ int *ptr;
+ int ret;
+
+ size = 2 * TWOMEG;
+
+ 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);
+
+ size = TWOMEG;
+ npages = size >> self->page_shift;
+ map = (void *)ALIGN((uintptr_t)buffer->ptr, size);
+ ret = madvise(map, size, MADV_HUGEPAGE);
+ ASSERT_EQ(ret, 0);
+ old_ptr = buffer->ptr;
+ buffer->ptr = map;
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ buffer->ptr = old_ptr;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Write huge TLBFS page.
+ */
+TEST_F(hmm, anon_write_hugetlbfs)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ long pagesizes[4];
+ int n, idx;
+
+ /* Skip test if we can't allocate a hugetlbfs page. */
+
+ n = gethugepagesizes(pagesizes, 4);
+ if (n <= 0)
+ return;
+ for (idx = 0; --n > 0; ) {
+ if (pagesizes[n] < pagesizes[idx])
+ idx = n;
+ }
+ size = ALIGN(TWOMEG, pagesizes[idx]);
+ npages = size >> self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->ptr = get_hugepage_region(size, GHR_STRICT);
+ if (buffer->ptr == NULL) {
+ free(buffer);
+ return;
+ }
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ free_hugepage_region(buffer->ptr);
+ buffer->ptr = NULL;
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Read mmap'ed file memory.
+ */
+TEST_F(hmm, file_read)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ int fd;
+ ssize_t len;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ fd = hmm_create_file(size);
+ ASSERT_GE(fd, 0);
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = fd;
+ buffer->size = size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ /* Write initial contents of the file. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+ len = pwrite(fd, buffer->mirror, size, 0);
+ ASSERT_EQ(len, size);
+ memset(buffer->mirror, 0, size);
+
+ buffer->ptr = mmap(NULL, size,
+ PROT_READ,
+ MAP_SHARED,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* Simulate a device reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* 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);
+}
+
+/*
+ * Write mmap'ed file memory.
+ */
+TEST_F(hmm, file_write)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+ int fd;
+ ssize_t len;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ fd = hmm_create_file(size);
+ ASSERT_GE(fd, 0);
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = fd;
+ buffer->size = size;
+ buffer->mirror = malloc(size);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ buffer->ptr = mmap(NULL, size,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* Initialize data that the device will write to buffer->ptr. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ptr[i] = i;
+
+ /* Simulate a device writing system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device wrote. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Check that the device also wrote the file. */
+ len = pread(fd, buffer->mirror, size, 0);
+ ASSERT_EQ(len, size);
+ 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.
+ */
+TEST_F(hmm, migrate)
+{
+ 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;
+
+ /* Migrate memory to device. */
+ 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);
+}
+
+/*
+ * Migrate anonymous memory to device private memory and fault it back to system
+ * memory.
+ */
+TEST_F(hmm, migrate_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;
+
+ /* Migrate memory to device. */
+ 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);
+
+ /* Fault pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Try to migrate various memory types to device private memory.
+ */
+TEST_F(hmm2, migrate_mixed)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ int *ptr;
+ unsigned char *p;
+ int ret;
+ int val;
+
+ npages = 6;
+ 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);
+
+ /* Reserve a range of addresses. */
+ buffer->ptr = mmap(NULL, size,
+ PROT_NONE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+ p = buffer->ptr;
+
+ /* Now try to migrate everything to device 1. */
+ ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, 6);
+
+ /* Punch a hole after the first page address. */
+ ret = munmap(buffer->ptr + self->page_size, self->page_size);
+ 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);
+ ASSERT_EQ(ret, -EINVAL);
+
+ /* Page 2 will be a read-only zero page. */
+ ret = mprotect(buffer->ptr + 2 * self->page_size, self->page_size,
+ PROT_READ);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 2 * self->page_size);
+ val = *ptr + 3;
+ ASSERT_EQ(val, 3);
+
+ /* Page 3 will be read-only. */
+ ret = mprotect(buffer->ptr + 3 * self->page_size, self->page_size,
+ PROT_READ | PROT_WRITE);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 3 * self->page_size);
+ *ptr = val;
+ ret = mprotect(buffer->ptr + 3 * self->page_size, self->page_size,
+ PROT_READ);
+ ASSERT_EQ(ret, 0);
+
+ /* Page 4 will be read-write. */
+ ret = mprotect(buffer->ptr + 4 * self->page_size, self->page_size,
+ PROT_READ | PROT_WRITE);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 4 * self->page_size);
+ *ptr = val;
+
+ /* 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);
+ ASSERT_EQ(ret, -ENOENT);
+ buffer->ptr = p;
+
+ /* Now try to migrate pages 2-3 to device 1. */
+ buffer->ptr = p + 2 * self->page_size;
+ ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, 2);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, 2);
+ buffer->ptr = p;
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Migrate anonymous memory to device private memory and fault it back to system
+ * memory multiple times.
+ */
+TEST_F(hmm, migrate_multiple)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ unsigned long c;
+ int *ptr;
+ int ret;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ for (c = 0; c < NTIMES; c++) {
+ 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;
+
+ /* Migrate memory to device. */
+ 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);
+
+ /* Fault pages back to system memory and check them. */
+ for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ hmm_buffer_free(buffer);
+ }
+}
+
+/*
+ * Read anonymous memory multiple times.
+ */
+TEST_F(hmm, anon_read_multiple)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ unsigned long c;
+ int *ptr;
+ int ret;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ for (c = 0; c < NTIMES; c++) {
+ 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 + c;
+
+ /* Simulate a device reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer,
+ npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i + c);
+
+ hmm_buffer_free(buffer);
+ }
+}
+
+void *unmap_buffer(void *p)
+{
+ struct hmm_buffer *buffer = p;
+
+ /* Delay for a bit and then unmap buffer while it is being read. */
+ hmm_nanosleep(hmm_random() % 32000);
+ munmap(buffer->ptr + buffer->size / 2, buffer->size / 2);
+ buffer->ptr = NULL;
+
+ return NULL;
+}
+
+/*
+ * Try reading anonymous memory while it is being unmapped.
+ */
+TEST_F(hmm, anon_teardown)
+{
+ unsigned long npages;
+ unsigned long size;
+ unsigned long c;
+ void *ret;
+
+ npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift;
+ ASSERT_NE(npages, 0);
+ size = npages << self->page_shift;
+
+ for (c = 0; c < NTIMES; ++c) {
+ pthread_t thread;
+ struct hmm_buffer *buffer;
+ unsigned long i;
+ int *ptr;
+ int rc;
+
+ 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 + c;
+
+ rc = pthread_create(&thread, NULL, unmap_buffer, buffer);
+ ASSERT_EQ(rc, 0);
+
+ /* Simulate a device reading system memory. */
+ rc = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_READ, buffer,
+ npages);
+ if (rc == 0) {
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror;
+ i < size / sizeof(*ptr);
+ ++i)
+ ASSERT_EQ(ptr[i], i + c);
+ }
+
+ pthread_join(thread, &ret);
+ hmm_buffer_free(buffer);
+ }
+}
+
+/*
+ * Test memory snapshot without faulting in pages accessed by the device.
+ */
+TEST_F(hmm2, snapshot)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ int *ptr;
+ unsigned char *p;
+ unsigned char *m;
+ int ret;
+ int val;
+
+ npages = 7;
+ size = npages << self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(npages);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ /* Reserve a range of addresses. */
+ buffer->ptr = mmap(NULL, size,
+ PROT_NONE,
+ MAP_PRIVATE | MAP_ANONYMOUS,
+ buffer->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+ p = buffer->ptr;
+
+ /* Punch a hole after the first page address. */
+ ret = munmap(buffer->ptr + self->page_size, self->page_size);
+ ASSERT_EQ(ret, 0);
+
+ /* Page 2 will be read-only zero page. */
+ ret = mprotect(buffer->ptr + 2 * self->page_size, self->page_size,
+ PROT_READ);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 2 * self->page_size);
+ val = *ptr + 3;
+ ASSERT_EQ(val, 3);
+
+ /* Page 3 will be read-only. */
+ ret = mprotect(buffer->ptr + 3 * self->page_size, self->page_size,
+ PROT_READ | PROT_WRITE);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 3 * self->page_size);
+ *ptr = val;
+ ret = mprotect(buffer->ptr + 3 * self->page_size, self->page_size,
+ PROT_READ);
+ ASSERT_EQ(ret, 0);
+
+ /* Page 4-6 will be read-write. */
+ ret = mprotect(buffer->ptr + 4 * self->page_size, 3 * self->page_size,
+ PROT_READ | PROT_WRITE);
+ ASSERT_EQ(ret, 0);
+ ptr = (int *)(buffer->ptr + 4 * self->page_size);
+ *ptr = val;
+
+ /* 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);
+ 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);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, 1);
+
+ /* Simulate a device snapshotting CPU pagetables. */
+ buffer->ptr = p;
+ ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_SNAPSHOT, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ /* Check what the device saw. */
+ m = buffer->mirror;
+ ASSERT_EQ(m[0], HMM_DMIRROR_PROT_NONE);
+ ASSERT_EQ(m[1], HMM_DMIRROR_PROT_NONE);
+ 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_DEV_PRIVATE_REMOTE |
+ HMM_DMIRROR_PROT_WRITE);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Test two devices reading the same memory (double mapped).
+ */
+TEST_F(hmm2, double_map)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned long i;
+ int *ptr;
+ int ret;
+
+ npages = 6;
+ size = npages << self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(npages);
+ ASSERT_NE(buffer->mirror, NULL);
+
+ /* Reserve a range of addresses. */
+ 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;
+
+ /* Make region read-only. */
+ ret = mprotect(buffer->ptr, size, PROT_READ);
+ ASSERT_EQ(ret, 0);
+
+ /* Simulate device 0 reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Simulate device 1 reading system memory. */
+ ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what the device read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
+
+ /* Punch a hole after the first page address. */
+ ret = munmap(buffer->ptr + self->page_size, self->page_size);
+ ASSERT_EQ(ret, 0);
+
+ hmm_buffer_free(buffer);
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests
index a692ea828317..ea3728570585 100755
--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -237,4 +237,20 @@ else
exitcode=1
fi

+echo "------------------------------------"
+echo "running HMM smoke test"
+echo "------------------------------------"
+./test_hmm.sh smoke
+ret_val=$?
+
+if [ $ret_val -eq 0 ]; then
+ echo "[PASS]"
+elif [ $ret_val -eq $ksft_skip ]; then
+ echo "[SKIP]"
+ exitcode=$ksft_skip
+else
+ echo "[FAIL]"
+ exitcode=1
+fi
+
exit $exitcode
diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
new file mode 100755
index 000000000000..461e4a99a362
--- /dev/null
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -0,0 +1,97 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2018 Uladzislau Rezki (Sony) <urezki@gmail.com>
+#
+# This is a test script for the kernel test driver to analyse vmalloc
+# allocator. Therefore it is just a kernel module loader. You can specify
+# and pass different parameters in order to:
+# a) analyse performance of vmalloc allocations;
+# b) stressing and stability check of vmalloc subsystem.
+
+TEST_NAME="test_hmm"
+DRIVER="test_hmm"
+
+# 1 if fails
+exitcode=1
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+check_test_requirements()
+{
+ uid=$(id -u)
+ if [ $uid -ne 0 ]; then
+ echo "$0: Must be run as root"
+ exit $ksft_skip
+ fi
+
+ if ! which modprobe > /dev/null 2>&1; then
+ echo "$0: You need modprobe installed"
+ exit $ksft_skip
+ fi
+
+ if ! modinfo $DRIVER > /dev/null 2>&1; then
+ echo "$0: You must have the following enabled in your kernel:"
+ echo "CONFIG_TEST_HMM=m"
+ exit $ksft_skip
+ fi
+}
+
+load_driver()
+{
+ modprobe $DRIVER > /dev/null 2>&1
+ 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
+ fi
+}
+
+unload_driver()
+{
+ modprobe -r $DRIVER > /dev/null 2>&1
+ rm -f /dev/hmm_dmirror?
+}
+
+run_smoke()
+{
+ echo "Running smoke test. Note, this test provides basic coverage."
+
+ load_driver
+ ./hmm-tests
+ unload_driver
+}
+
+usage()
+{
+ echo -n "Usage: $0"
+ echo
+ echo "Example usage:"
+ echo
+ echo "# Shows help message"
+ echo "./${TEST_NAME}.sh"
+ echo
+ echo "# Smoke testing"
+ echo "./${TEST_NAME}.sh smoke"
+ echo
+ exit 0
+}
+
+function run_test()
+{
+ if [ $# -eq 0 ]; then
+ usage
+ else
+ if [ "$1" = "smoke" ]; then
+ run_smoke
+ else
+ usage
+ fi
+ fi
+}
+
+check_test_requirements
+run_test $@
+
+exit 0
--
2.20.1
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