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Subject[PATCH 4/4] mm/hmm/test: add self tests for HMM
Date
Add self tests for HMM.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
---
MAINTAINERS | 3 +
drivers/char/Kconfig | 11 +
drivers/char/Makefile | 1 +
drivers/char/hmm_dmirror.c | 1504 ++++++++++++++++++++++++
include/Kbuild | 1 +
include/uapi/linux/hmm_dmirror.h | 74 ++
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 3 +
tools/testing/selftests/vm/config | 3 +
tools/testing/selftests/vm/hmm-tests.c | 1304 ++++++++++++++++++++
tools/testing/selftests/vm/run_vmtests | 16 +
tools/testing/selftests/vm/test_hmm.sh | 105 ++
12 files changed, 3026 insertions(+)
create mode 100644 drivers/char/hmm_dmirror.c
create mode 100644 include/uapi/linux/hmm_dmirror.h
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 43604d6ab96c..8ab242d91876 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7318,8 +7318,11 @@ M: Jérôme Glisse <jglisse@redhat.com>
L: linux-mm@kvack.org
S: Maintained
F: mm/hmm*
+F: drivers/char/hmm*
F: include/linux/hmm*
+F: include/uapi/linux/hmm*
F: Documentation/vm/hmm.rst
+F: tools/testing/selftests/vm/*hmm*

HOST AP DRIVER
M: Jouni Malinen <j@w1.fi>
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 3e866885a405..b4ad868ead63 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -557,6 +557,17 @@ config ADI
and SSM (Silicon Secured Memory). Intended consumers of this
driver include crash and makedumpfile.

+config HMM_DMIRROR
+ tristate "HMM driver for testing Heterogeneous Memory Management"
+ depends on HMM_MIRROR
+ depends on DEVICE_PRIVATE
+ help
+ This is a pseudo device driver solely for testing HMM.
+ Say Y here if you want to build the HMM test driver.
+ Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
+
+ If in doubt, say "N".
+
endmenu

config RANDOM_TRUST_CPU
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index fbea7dd12932..c9ddd8e550c5 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -54,3 +54,4 @@ js-rtc-y = rtc.o
obj-$(CONFIG_XILLYBUS) += xillybus/
obj-$(CONFIG_POWERNV_OP_PANEL) += powernv-op-panel.o
obj-$(CONFIG_ADI) += adi.o
+obj-$(CONFIG_HMM_DMIRROR) += hmm_dmirror.o
diff --git a/drivers/char/hmm_dmirror.c b/drivers/char/hmm_dmirror.c
new file mode 100644
index 000000000000..ccb4e03a03b5
--- /dev/null
+++ b/drivers/char/hmm_dmirror.c
@@ -0,0 +1,1504 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2013 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Jérôme Glisse <jglisse@redhat.com>
+ */
+/*
+ * This is a driver to exercice 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.
+ *
+ * In some ways it can also serve as an example driver for people wanting to use
+ * HMM inside their own device driver.
+ */
+#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/hmm_dmirror.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 dev_t dmirror_dev;
+static struct platform_device *dmirror_platform_devices[DMIRROR_NDEVICES];
+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_ZPAGE 0x20UL
+
+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] = 0x20, /* actually, read-only zero page */
+};
+
+struct dmirror_pt {
+ atomic64_t pgd[PTRS_PER_PGD];
+ struct rw_semaphore lock;
+};
+
+/*
+ * Data attached to the open device file.
+ * Note that it might be shared after a fork().
+ */
+struct dmirror {
+ struct dmirror_device *mdevice;
+ struct hmm_mirror mirror;
+ struct dmirror_pt pt;
+};
+
+/*
+ * 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;
+ struct platform_device *pdevice;
+
+ 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 inline unsigned long dmirror_pt_pgd(unsigned long addr)
+{
+ return (addr >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1);
+}
+
+static inline unsigned long dmirror_pt_pud(unsigned long addr)
+{
+ return (addr >> PUD_SHIFT) & (PTRS_PER_PUD - 1);
+}
+
+static inline unsigned long dmirror_pt_pmd(unsigned long addr)
+{
+ return (addr >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
+}
+
+static inline unsigned long dmirror_pt_pte(unsigned long addr)
+{
+ return (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
+}
+
+static inline struct page *dmirror_pt_page(atomic64_t *dptep)
+{
+ s64 dpte = atomic64_read(dptep);
+
+ if (dpte == DPT_ZPAGE)
+ return dmirror_zero_page;
+ if (!(dpte & DPT_VALID))
+ return NULL;
+ return pfn_to_page((u64)dpte >> DPT_SHIFT);
+}
+
+static inline struct page *dmirror_pt_page_write(atomic64_t *dptep)
+{
+ s64 dpte = atomic64_read(dptep);
+
+ if (!(dpte & DPT_VALID) || !(dpte & DPT_WRITE))
+ return NULL;
+ return pfn_to_page((u64)dpte >> DPT_SHIFT);
+}
+
+static inline s64 dmirror_pt_from_page(struct page *page)
+{
+ if (!page)
+ return 0;
+ return (page_to_pfn(page) << DPT_SHIFT) | DPT_VALID;
+}
+
+static struct page *populate_pt(atomic64_t *dptep)
+{
+ struct page *page;
+ s64 new_dpte;
+ s64 old_dpte;
+
+ page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
+ if (page) {
+ new_dpte = dmirror_pt_from_page(page);
+ old_dpte = atomic64_cmpxchg(dptep, 0, new_dpte);
+ if (old_dpte) {
+ __free_page(page);
+ page = pfn_to_page((u64)old_dpte >> DPT_SHIFT);
+ }
+ }
+ return page;
+}
+
+static inline unsigned long dmirror_pt_pud_end(unsigned long addr)
+{
+ return (addr & PGDIR_MASK) + ((unsigned long)PTRS_PER_PUD << PUD_SHIFT);
+}
+
+static inline unsigned long dmirror_pt_pmd_end(unsigned long addr)
+{
+ return (addr & PUD_MASK) + ((unsigned long)PTRS_PER_PMD << PMD_SHIFT);
+}
+
+static inline unsigned long dmirror_pt_pte_end(unsigned long addr)
+{
+ return (addr & PMD_MASK) + ((unsigned long)PTRS_PER_PTE << PAGE_SHIFT);
+}
+
+typedef int (*dmirror_walk_cb_t)(struct dmirror *dmirror,
+ unsigned long start,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private);
+
+static int dmirror_pt_walk(struct dmirror *dmirror,
+ dmirror_walk_cb_t cb,
+ unsigned long start,
+ unsigned long end,
+ void *private,
+ bool populate)
+{
+ atomic64_t *dpgdp = &dmirror->pt.pgd[dmirror_pt_pgd(start)];
+ unsigned long addr;
+
+ for (addr = start; addr < end; dpgdp++) {
+ atomic64_t *dpudp;
+ unsigned long pud_end;
+ struct page *pud_page;
+
+ pud_end = min(end, dmirror_pt_pud_end(addr));
+ pud_page = dmirror_pt_page(dpgdp);
+ if (!pud_page) {
+ if (!populate) {
+ addr = pud_end;
+ continue;
+ }
+ pud_page = populate_pt(dpgdp);
+ if (!pud_page)
+ return -ENOMEM;
+ }
+ dpudp = kmap(pud_page);
+ dpudp += dmirror_pt_pud(addr);
+ for (; addr != pud_end; dpudp++) {
+ atomic64_t *dpmdp;
+ unsigned long pmd_end;
+ struct page *pmd_page;
+
+ pmd_end = min(end, dmirror_pt_pmd_end(addr));
+ pmd_page = dmirror_pt_page(dpudp);
+ if (!pmd_page) {
+ if (!populate) {
+ addr = pmd_end;
+ continue;
+ }
+ pmd_page = populate_pt(dpudp);
+ if (!pmd_page) {
+ kunmap(pud_page);
+ return -ENOMEM;
+ }
+ }
+ dpmdp = kmap(pmd_page);
+ dpmdp += dmirror_pt_pmd(addr);
+ for (; addr != pmd_end; dpmdp++) {
+ atomic64_t *dptep;
+ unsigned long pte_end;
+ struct page *pte_page;
+ int ret;
+
+ pte_end = min(end, dmirror_pt_pte_end(addr));
+ pte_page = dmirror_pt_page(dpmdp);
+ if (!pte_page) {
+ if (!populate) {
+ addr = pte_end;
+ continue;
+ }
+ pte_page = populate_pt(dpmdp);
+ if (!pte_page) {
+ kunmap(pmd_page);
+ kunmap(pud_page);
+ return -ENOMEM;
+ }
+ }
+ dptep = kmap(pte_page);
+ dptep += dmirror_pt_pte(addr);
+ ret = cb(dmirror, addr, pte_end, dptep,
+ private);
+ kunmap(pte_page);
+ addr = pte_end;
+ if (ret) {
+ kunmap(pmd_page);
+ kunmap(pud_page);
+ return ret;
+ }
+ }
+ kunmap(pmd_page);
+ addr = pmd_end;
+ }
+ kunmap(pud_page);
+ addr = pud_end;
+ }
+
+ return 0;
+}
+
+static void dmirror_pt_free(struct dmirror *dmirror)
+{
+ atomic64_t *dpgdp = dmirror->pt.pgd;
+
+ for (; dpgdp != dmirror->pt.pgd + PTRS_PER_PGD; dpgdp++) {
+ atomic64_t *dpudp;
+ atomic64_t *dpudp_end;
+ struct page *pud_page;
+
+ pud_page = dmirror_pt_page(dpgdp);
+ if (!pud_page)
+ continue;
+
+ dpudp = kmap(pud_page);
+ dpudp_end = dpudp + PTRS_PER_PUD;
+ for (; dpudp != dpudp_end; dpudp++) {
+ atomic64_t *dpmdp;
+ atomic64_t *dpmdp_end;
+ struct page *pmd_page;
+
+ pmd_page = dmirror_pt_page(dpudp);
+ if (!pmd_page)
+ continue;
+
+ dpmdp = kmap(pmd_page);
+ dpmdp_end = dpmdp + PTRS_PER_PMD;
+ for (; dpmdp != dpmdp_end; dpmdp++) {
+ struct page *pte_page;
+
+ pte_page = dmirror_pt_page(dpmdp);
+ if (!pte_page)
+ continue;
+
+ atomic64_set(dpmdp, 0);
+ __free_page(pte_page);
+ }
+ kunmap(pmd_page);
+ atomic64_set(dpudp, 0);
+ __free_page(pmd_page);
+ }
+ kunmap(pud_page);
+ atomic64_set(dpgdp, 0);
+ __free_page(pud_page);
+ }
+}
+
+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 int dmirror_bounce_copy_from(struct dmirror_bounce *bounce,
+ unsigned long addr)
+{
+ unsigned long end = addr + bounce->size;
+ char __user *uptr = (void __user *)addr;
+ void *ptr = bounce->ptr;
+
+ for (; addr < end; addr += PAGE_SIZE, ptr += PAGE_SIZE,
+ uptr += PAGE_SIZE) {
+ int ret;
+
+ ret = copy_from_user(ptr, uptr, PAGE_SIZE);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int dmirror_bounce_copy_to(struct dmirror_bounce *bounce,
+ unsigned long addr)
+{
+ unsigned long end = addr + bounce->size;
+ char __user *uptr = (void __user *)addr;
+ void *ptr = bounce->ptr;
+
+ for (; addr < end; addr += PAGE_SIZE, ptr += PAGE_SIZE,
+ uptr += PAGE_SIZE) {
+ int ret;
+
+ ret = copy_to_user(uptr, ptr, PAGE_SIZE);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
+{
+ vfree(bounce->ptr);
+}
+
+static int dmirror_do_update(struct dmirror *dmirror,
+ unsigned long addr,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private)
+{
+ for (; addr < end; addr += PAGE_SIZE, ++dptep) {
+ /* Clear pte */
+ atomic64_set(dptep, 0);
+ }
+
+ return 0;
+}
+
+static int dmirror_update(struct hmm_mirror *mirror,
+ const struct mmu_notifier_range *update)
+{
+ struct dmirror *dmirror = container_of(mirror, struct dmirror, mirror);
+
+ (void) dmirror_pt_walk(dmirror, dmirror_do_update, update->start,
+ update->end, NULL, false);
+ return 0;
+}
+
+static const struct hmm_mirror_ops dmirror_ops = {
+ .sync_cpu_device_pagetables = &dmirror_update,
+};
+
+/*
+ * dmirror_new() - allocate and initialize dmirror struct.
+ *
+ * @mdevice: The device this mirror is associated with.
+ * @filp: The active device file descriptor this mirror is associated with.
+ */
+static struct dmirror *dmirror_new(struct dmirror_device *mdevice)
+{
+ struct mm_struct *mm = get_task_mm(current);
+ struct dmirror *dmirror;
+ int ret;
+
+ if (!mm)
+ goto err;
+
+ /* Mirror this process address space */
+ dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL);
+ if (dmirror == NULL)
+ goto err_mmput;
+
+ dmirror->mdevice = mdevice;
+ dmirror->mirror.ops = &dmirror_ops;
+ down_write(&mm->mmap_sem);
+ ret = hmm_mirror_register(&dmirror->mirror, mm);
+ up_write(&mm->mmap_sem);
+ if (ret)
+ goto err_free;
+
+ mmput(mm);
+ return dmirror;
+
+err_free:
+ kfree(dmirror);
+err_mmput:
+ mmput(mm);
+err:
+ return NULL;
+}
+
+static void dmirror_del(struct dmirror *dmirror)
+{
+ hmm_mirror_unregister(&dmirror->mirror);
+ dmirror_pt_free(dmirror);
+ kfree(dmirror);
+}
+
+/*
+ * Below are the file operation for the dmirror device file. Only ioctl matters.
+ *
+ * Note this is highly specific to the dmirror device driver and should not be
+ * construed as an example on how to design the API a real device driver would
+ * expose to userspace.
+ */
+static ssize_t dmirror_fops_read(struct file *filp,
+ char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ return -EINVAL;
+}
+
+static ssize_t dmirror_fops_write(struct file *filp,
+ const char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ return -EINVAL;
+}
+
+static int dmirror_fops_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ /* Forbid mmap of the dmirror device file. */
+ return -EINVAL;
+}
+
+static int dmirror_fops_open(struct inode *inode, struct file *filp)
+{
+ struct cdev *cdev = inode->i_cdev;
+ struct dmirror_device *mdevice;
+ struct dmirror *dmirror;
+
+ /* No exclusive opens. */
+ if (filp->f_flags & O_EXCL)
+ return -EINVAL;
+
+ mdevice = container_of(cdev, struct dmirror_device, cdevice);
+ dmirror = dmirror_new(mdevice);
+ filp->private_data = dmirror;
+
+ return dmirror ? 0 : -ENOMEM;
+}
+
+static int dmirror_fops_release(struct inode *inode, struct file *filp)
+{
+ struct dmirror *dmirror = filp->private_data;
+
+ if (!dmirror)
+ return 0;
+
+ dmirror_del(dmirror);
+ filp->private_data = NULL;
+
+ return 0;
+}
+
+static int dmirror_do_fault(struct dmirror *dmirror,
+ unsigned long addr,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private)
+{
+ struct hmm_range *range = private;
+ unsigned long idx = (addr - range->start) >> PAGE_SHIFT;
+ uint64_t *pfns = range->pfns;
+
+ for (; addr < end; addr += PAGE_SIZE, ++dptep, ++idx) {
+ struct page *page;
+ s64 dpte;
+
+ /*
+ * 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[idx] == range->values[HMM_PFN_ERROR])
+ return -EFAULT;
+ /*
+ * The only special PFN HMM returns is the read-only zero page
+ * which doesn't have a matching struct page.
+ */
+ if (pfns[idx] == range->values[HMM_PFN_SPECIAL]) {
+ atomic64_set(dptep, DPT_ZPAGE);
+ continue;
+ }
+ if (!(pfns[idx] & range->flags[HMM_PFN_VALID]))
+ return -EFAULT;
+ page = hmm_device_entry_to_page(range, pfns[idx]);
+ dpte = dmirror_pt_from_page(page);
+ if (pfns[idx] & range->flags[HMM_PFN_WRITE])
+ dpte |= DPT_WRITE;
+ else if (range->default_flags & range->flags[HMM_PFN_WRITE])
+ return -EFAULT;
+ atomic64_set(dptep, dpte);
+ }
+
+ return 0;
+}
+
+static int dmirror_fault(struct dmirror *dmirror,
+ unsigned long start,
+ unsigned long end,
+ bool write)
+{
+ struct mm_struct *mm = dmirror->mirror.hmm->mmu_notifier.mm;
+ unsigned long addr;
+ unsigned long next;
+ uint64_t pfns[64];
+ struct hmm_range range;
+ int ret = 0;
+
+ range.pfns = pfns;
+ range.flags = dmirror_hmm_flags;
+ range.values = dmirror_hmm_values;
+ range.pfn_shift = DPT_SHIFT;
+ range.pfn_flags_mask = ~(range.flags[HMM_PFN_VALID] |
+ range.flags[HMM_PFN_WRITE]);
+ range.default_flags = range.flags[HMM_PFN_VALID];
+ if (write)
+ range.default_flags |= range.flags[HMM_PFN_WRITE];
+
+ for (addr = start; addr < end; ) {
+ long count;
+
+ next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
+ range.start = addr;
+ range.end = next;
+
+ down_read(&mm->mmap_sem);
+
+ ret = hmm_range_register(&range, &dmirror->mirror);
+ if (ret) {
+ up_read(&mm->mmap_sem);
+ break;
+ }
+
+ if (!hmm_range_wait_until_valid(&range,
+ DMIRROR_RANGE_FAULT_TIMEOUT)) {
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ continue;
+ }
+
+ count = hmm_range_fault(&range, 0);
+ if (count < 0) {
+ ret = count;
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ break;
+ }
+
+ if (!hmm_range_valid(&range)) {
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ continue;
+ }
+ ret = dmirror_pt_walk(dmirror, dmirror_do_fault,
+ addr, next, &range, true);
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ if (ret)
+ break;
+
+ addr = next;
+ }
+
+ return ret;
+}
+
+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_read(struct dmirror *dmirror,
+ unsigned long addr,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private)
+{
+ struct dmirror_bounce *bounce = private;
+ void *ptr;
+
+ ptr = bounce->ptr + ((addr - bounce->addr) & PAGE_MASK);
+
+ for (; addr < end; addr += PAGE_SIZE, ++dptep) {
+ struct page *page;
+ void *tmp;
+
+ page = dmirror_pt_page(dptep);
+ if (!page)
+ return -ENOENT;
+ if (is_zone_device_page(page)) {
+ if (!dmirror_device_is_mine(dmirror->mdevice, page))
+ return -ENOENT;
+ page = page->zone_device_data;
+ }
+
+ 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;
+
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ return ret;
+
+again:
+ ret = dmirror_pt_walk(dmirror, dmirror_do_read,
+ start, end, &bounce, true);
+ if (ret == 0)
+ ret = dmirror_bounce_copy_to(&bounce, cmd->ptr);
+ 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 addr,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private)
+{
+ struct dmirror_bounce *bounce = private;
+ void *ptr;
+
+ ptr = bounce->ptr + ((addr - bounce->addr) & PAGE_MASK);
+
+ for (; addr < end; addr += PAGE_SIZE, ++dptep) {
+ struct page *page;
+ void *tmp;
+
+ page = dmirror_pt_page_write(dptep);
+ if (!page)
+ return -ENOENT;
+ if (is_zone_device_page(page)) {
+ if (!dmirror_device_is_mine(dmirror->mdevice, page))
+ return -ENOENT;
+ page = page->zone_device_data;
+ }
+
+ 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;
+
+ ret = dmirror_bounce_init(&bounce, start, size);
+ if (ret)
+ return ret;
+ ret = dmirror_bounce_copy_from(&bounce, cmd->ptr);
+ if (ret)
+ return ret;
+
+again:
+ ret = dmirror_pt_walk(dmirror, dmirror_do_write,
+ start, end, &bounce, true);
+ 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 = devm_request_free_mem_region(&mdevice->pdevice->dev,
+ &iomem_resource, DEVMEM_CHUNK_SIZE);
+ 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 = devm_memremap_pages(&mdevice->pdevice->dev, &devmem->pagemap);
+ 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 fake
+ * our device memory.
+ */
+ rpage = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
+ 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:
+ spin_unlock(&mdevice->lock);
+ __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_pfns = args->src;
+ unsigned long *dst_pfns = args->dst;
+ unsigned long addr;
+
+ for (addr = args->start; addr < args->end; addr += PAGE_SIZE,
+ src_pfns++, dst_pfns++) {
+ struct page *spage;
+ struct page *dpage;
+ struct page *rpage;
+
+ if (!(*src_pfns & 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_pfns);
+ if (spage && is_zone_device_page(spage)) {
+ if (!dmirror_device_is_mine(mdevice, spage))
+ continue;
+ spage = spage->zone_device_data;
+ }
+
+ 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_pfns = migrate_pfn(page_to_pfn(dpage)) |
+ MIGRATE_PFN_LOCKED;
+ if ((*src_pfns & MIGRATE_PFN_WRITE) ||
+ (!spage && args->vma->vm_flags & VM_WRITE))
+ *dst_pfns |= MIGRATE_PFN_WRITE;
+ }
+}
+
+struct dmirror_migrate {
+ struct hmm_dmirror_cmd *cmd;
+ const unsigned long *mpfns;
+ unsigned long start;
+};
+
+static int dmirror_do_migrate(struct dmirror *dmirror,
+ unsigned long addr,
+ unsigned long end,
+ atomic64_t *dptep,
+ void *private)
+{
+ struct dmirror_migrate *migrate = private;
+ const unsigned long *mpfns = migrate->mpfns;
+ unsigned long idx = (addr - migrate->start) >> PAGE_SHIFT;
+
+ for (; addr < end; addr += PAGE_SIZE, ++dptep, ++idx) {
+ unsigned long mpfn = mpfns[idx];
+ struct page *page;
+ s64 dpte;
+
+ page = migrate_pfn_to_page(mpfn);
+ if (!page)
+ continue;
+
+ dpte = dmirror_pt_from_page(page) | DPT_DPAGE;
+ if (mpfn & MIGRATE_PFN_WRITE)
+ dpte |= DPT_WRITE;
+ atomic64_set(dptep, dpte);
+ }
+
+ return 0;
+}
+
+static void dmirror_migrate_finalize_and_map(struct migrate_vma *args,
+ struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ struct dmirror_migrate migrate;
+
+ migrate.cmd = cmd;
+ migrate.mpfns = args->dst;
+ migrate.start = args->start;
+
+ /* Map the migrated pages into the device's page tables. */
+ (void) dmirror_pt_walk(dmirror, dmirror_do_migrate, args->start,
+ args->end, &migrate, true);
+}
+
+static int dmirror_migrate(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ unsigned long addr = cmd->addr;
+ unsigned long end = addr + (cmd->npages << PAGE_SHIFT);
+ struct mm_struct *mm = dmirror->mirror.hmm->mmu_notifier.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;
+
+ down_read(&mm->mmap_sem);
+ for (; addr < end; addr = next) {
+ next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
+
+ vma = find_vma(mm, addr);
+ if (!vma || addr < vma->vm_start) {
+ ret = -EINVAL;
+ goto out;
+ }
+ 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, cmd);
+ migrate_vma_finalize(&args);
+ }
+ up_read(&mm->mmap_sem);
+
+ /* Return the migrated data for verification. */
+ ret = dmirror_bounce_init(&bounce, cmd->addr, end - cmd->addr);
+ if (ret)
+ return ret;
+ ret = dmirror_pt_walk(dmirror, dmirror_do_read,
+ cmd->addr, end, &bounce, true);
+ if (ret == 0)
+ ret = dmirror_bounce_copy_to(&bounce, cmd->ptr);
+ cmd->cpages = bounce.cpages;
+ dmirror_bounce_fini(&bounce);
+ return ret;
+
+out:
+ up_read(&mm->mmap_sem);
+ 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;
+ }
+ if (entry == range->values[HMM_PFN_NONE]) {
+ *perm = HMM_DMIRROR_PROT_NONE;
+ return;
+ }
+ if (entry == range->values[HMM_PFN_SPECIAL]) {
+ *perm = HMM_DMIRROR_PROT_ZERO;
+ return;
+ }
+ if (!(entry & range->flags[HMM_PFN_VALID])) {
+ *perm = HMM_DMIRROR_PROT_NONE;
+ return;
+ }
+ page = hmm_device_entry_to_page(range, entry);
+ if (!page)
+ *perm = HMM_DMIRROR_PROT_ZERO;
+ else 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
+ *perm = HMM_DMIRROR_PROT_NONE;
+ if (entry & range->flags[HMM_PFN_WRITE])
+ *perm |= HMM_DMIRROR_PROT_WRITE;
+ else
+ *perm |= HMM_DMIRROR_PROT_READ;
+}
+
+static int dmirror_snapshot(struct dmirror *dmirror,
+ struct hmm_dmirror_cmd *cmd)
+{
+ struct mm_struct *mm = dmirror->mirror.hmm->mmu_notifier.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;
+ int ret = 0;
+
+ start = cmd->addr;
+ end = start + size;
+ uptr = (void __user *)cmd->ptr;
+
+ range.pfns = pfns;
+ range.flags = dmirror_hmm_flags;
+ range.values = dmirror_hmm_values;
+ range.pfn_shift = DPT_SHIFT;
+ range.pfn_flags_mask = ~0ULL;
+ range.default_flags = 0;
+
+ for (addr = start; addr < end; ) {
+ long count;
+ unsigned long i;
+ unsigned long n;
+
+ next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
+ range.start = addr;
+ range.end = next;
+
+ down_read(&mm->mmap_sem);
+
+ ret = hmm_range_register(&range, &dmirror->mirror);
+ if (ret) {
+ up_read(&mm->mmap_sem);
+ break;
+ }
+
+ if (!hmm_range_wait_until_valid(&range,
+ DMIRROR_RANGE_FAULT_TIMEOUT)) {
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ continue;
+ }
+
+ count = hmm_range_fault(&range, HMM_FAULT_SNAPSHOT);
+ if (count < 0) {
+ ret = count;
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ if (ret == -EBUSY)
+ continue;
+ break;
+ }
+
+ if (!hmm_range_valid(&range)) {
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+ continue;
+ }
+
+ n = (next - addr) >> PAGE_SHIFT;
+ for (i = 0; i < n; i++)
+ dmirror_mkentry(dmirror, &range, perm + i, pfns[i]);
+ hmm_range_unregister(&range);
+ up_read(&mm->mmap_sem);
+
+ ret = copy_to_user(uptr, perm, n);
+ if (ret)
+ break;
+
+ cmd->cpages += n;
+ uptr += n;
+ addr = next;
+ }
+
+ 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 = {
+ .read = dmirror_fops_read,
+ .write = dmirror_fops_write,
+ .mmap = dmirror_fops_mmap,
+ .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_pfns = args->src;
+ unsigned long *dst_pfns = args->dst;
+ unsigned long start = args->start;
+ unsigned long end = args->end;
+ unsigned long addr;
+
+ for (addr = start; addr < end; addr += PAGE_SIZE,
+ src_pfns++, dst_pfns++) {
+ struct page *dpage, *spage;
+
+ spage = migrate_pfn_to_page(*src_pfns);
+ if (!spage || !(*src_pfns & 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_pfns = migrate_pfn(page_to_pfn(dpage)) |
+ MIGRATE_PFN_LOCKED;
+ if (*src_pfns & MIGRATE_PFN_WRITE)
+ *dst_pfns |= 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. */
+ (void) dmirror_pt_walk(dmirror, dmirror_do_update, args->start,
+ args->end, NULL, false);
+}
+
+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 void dmirror_pdev_del(void *arg)
+{
+ struct dmirror_device *mdevice = arg;
+ unsigned int i;
+
+ if (mdevice->devmem_chunks) {
+ for (i = 0; i < mdevice->devmem_count; i++)
+ kfree(mdevice->devmem_chunks[i]);
+ kfree(mdevice->devmem_chunks);
+ }
+
+ cdev_del(&mdevice->cdevice);
+ kfree(mdevice);
+}
+
+static int dmirror_probe(struct platform_device *pdev)
+{
+ struct dmirror_device *mdevice;
+ int ret;
+
+ mdevice = kzalloc(sizeof(*mdevice), GFP_KERNEL);
+ if (!mdevice)
+ return -ENOMEM;
+
+ mdevice->pdevice = pdev;
+ mutex_init(&mdevice->devmem_lock);
+ spin_lock_init(&mdevice->lock);
+
+ cdev_init(&mdevice->cdevice, &dmirror_fops);
+ ret = cdev_add(&mdevice->cdevice, pdev->dev.devt, 1);
+ if (ret) {
+ kfree(mdevice);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, mdevice);
+ ret = devm_add_action_or_reset(&pdev->dev, dmirror_pdev_del, mdevice);
+ if (ret)
+ return ret;
+
+ /* Build list of free struct page */
+ dmirror_allocate_chunk(mdevice, NULL);
+
+ return 0;
+}
+
+static int dmirror_remove(struct platform_device *pdev)
+{
+ /* all probe actions are unwound by devm */
+ return 0;
+}
+
+static struct platform_driver dmirror_device_driver = {
+ .probe = dmirror_probe,
+ .remove = dmirror_remove,
+ .driver = {
+ .name = "HMM_DMIRROR",
+ },
+};
+
+static int __init hmm_dmirror_init(void)
+{
+ int ret;
+ int id;
+
+ ret = platform_driver_register(&dmirror_device_driver);
+ if (ret)
+ return ret;
+
+ ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
+ "HMM_DMIRROR");
+ if (ret)
+ goto err_unreg;
+
+ for (id = 0; id < DMIRROR_NDEVICES; id++) {
+ struct platform_device *pd;
+
+ pd = platform_device_alloc("HMM_DMIRROR", id);
+ if (!pd) {
+ ret = -ENOMEM;
+ goto err_chrdev;
+ }
+ pd->dev.devt = MKDEV(MAJOR(dmirror_dev), id);
+ ret = platform_device_add(pd);
+ if (ret) {
+ platform_device_put(pd);
+ goto err_chrdev;
+ }
+ dmirror_platform_devices[id] = pd;
+ }
+
+ /*
+ * 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_dmirror loaded. This is only for testing HMM.\n");
+ return 0;
+
+err_chrdev:
+ while (--id >= 0) {
+ platform_device_unregister(dmirror_platform_devices[id]);
+ dmirror_platform_devices[id] = NULL;
+ }
+ unregister_chrdev_region(dmirror_dev, 1);
+err_unreg:
+ platform_driver_unregister(&dmirror_device_driver);
+ 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++)
+ platform_device_unregister(dmirror_platform_devices[id]);
+ unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
+ platform_driver_unregister(&dmirror_device_driver);
+ mmu_notifier_synchronize();
+}
+
+module_init(hmm_dmirror_init);
+module_exit(hmm_dmirror_exit);
+MODULE_LICENSE("GPL");
diff --git a/include/Kbuild b/include/Kbuild
index c38f0d46b267..972c168629cd 100644
--- a/include/Kbuild
+++ b/include/Kbuild
@@ -1134,6 +1134,7 @@ header-test- += uapi/linux/coda_psdev.h
header-test- += uapi/linux/errqueue.h
header-test- += uapi/linux/eventpoll.h
header-test- += uapi/linux/hdlc/ioctl.h
+header-test- += uapi/linux/hmm_dmirror.h
header-test- += uapi/linux/input.h
header-test- += uapi/linux/kvm.h
header-test- += uapi/linux/kvm_para.h
diff --git a/include/uapi/linux/hmm_dmirror.h b/include/uapi/linux/hmm_dmirror.h
new file mode 100644
index 000000000000..b886210142ad
--- /dev/null
+++ b/include/uapi/linux/hmm_dmirror.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright 2013 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Jérôme Glisse <jglisse@redhat.com>
+ */
+/*
+ * This is a dummy driver to exercise the HMM (heterogeneous memory management)
+ * API of the kernel. It allows a userspace program to expose its entire address
+ * space through the HMM dummy driver file.
+ */
+#ifndef _UAPI_LINUX_HMM_DMIRROR_H
+#define _UAPI_LINUX_HMM_DMIRROR_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+/*
+ * Structure to pass to the HMM test driver to mimic a device accessing
+ * system memory and ZONE_DEVICE private memory through device page tables.
+ *
+ * @addr: (in) user address the device will read/write
+ * @ptr: (in) user address where device data is copied to/from
+ * @npages: (in) number of pages to read/write
+ * @cpages: (out) number of pages copied
+ * @faults: (out) number of device page faults seen
+ */
+struct hmm_dmirror_cmd {
+ __u64 addr;
+ __u64 ptr;
+ __u64 npages;
+ __u64 cpages;
+ __u64 faults;
+};
+
+/* Expose the address space of the calling process through hmm dummy dev 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)
+
+/*
+ * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
+ * HMM_DMIRROR_PROT_ERROR: no valid mirror PTE for this page
+ * HMM_DMIRROR_PROT_NONE: unpopulated PTE or PTE with no access
+ * HMM_DMIRROR_PROT_READ: read-only PTE
+ * HMM_DMIRROR_PROT_WRITE: read/write PTE
+ * HMM_DMIRROR_PROT_ZERO: special read-only zero page
+ * HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL: Migrated device private page on the
+ * device the ioctl() is made
+ * HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
+ * other device
+ */
+enum {
+ HMM_DMIRROR_PROT_ERROR = 0xFF,
+ HMM_DMIRROR_PROT_NONE = 0x00,
+ HMM_DMIRROR_PROT_READ = 0x01,
+ HMM_DMIRROR_PROT_WRITE = 0x02,
+ HMM_DMIRROR_PROT_ZERO = 0x10,
+ HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL = 0x20,
+ HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,
+};
+
+#endif /* _UAPI_LINUX_HMM_DMIRROR_H */
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 9534dc2bc929..5643cfb5e3d6 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -5,6 +5,7 @@ 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
@@ -26,6 +27,8 @@ 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 1c0d76cb5adf..34cfab18e737 100644
--- a/tools/testing/selftests/vm/config
+++ b/tools/testing/selftests/vm/config
@@ -1,2 +1,5 @@
CONFIG_SYSVIPC=y
CONFIG_USERFAULTFD=y
+CONFIG_HMM_MIRROR=y
+CONFIG_DEVICE_PRIVATE=y
+CONFIG_HMM_DMIRROR=m
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
new file mode 100644
index 000000000000..78756e72e5c2
--- /dev/null
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -0,0 +1,1304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2013 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Jérôme Glisse <jglisse@redhat.com>
+ */
+
+/*
+ * 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/hmm_dmirror.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);
+}
+
+/*
+ * 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;
+ off_t off;
+ 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;
+ off = lseek(fd, 0, SEEK_SET);
+ ASSERT_EQ(off, 0);
+ len = write(fd, buffer->mirror, size);
+ 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;
+ off_t off;
+ 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. */
+ off = lseek(fd, 0, SEEK_SET);
+ ASSERT_EQ(off, 0);
+ len = read(fd, buffer->mirror, size);
+ 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);
+ 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_HARNESS_MAIN
diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests
index 951c507a27f7..634cfefdaffd 100755
--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -227,4 +227,20 @@ 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 $exitcode
diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
new file mode 100755
index 000000000000..069a39f85876
--- /dev/null
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -0,0 +1,105 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2018 Uladzislau Rezki (Sony) <urezki@gmail.com>
+#
+# This is a test script for the kernel test driver to analyse vmalloc
+# allocator. Therefore it is just a kernel module loader. You can specify
+# and pass different parameters in order to:
+# a) analyse performance of vmalloc allocations;
+# b) stressing and stability check of vmalloc subsystem.
+
+TEST_NAME="test_hmm"
+DRIVER="hmm_dmirror"
+
+# 1 if fails
+exitcode=1
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+#
+# Static templates for performance, stressing and smoke tests.
+# Also it is possible to pass any supported parameters manualy.
+#
+PERF_PARAM="single_cpu_test=1 sequential_test_order=1 test_repeat_count=3"
+SMOKE_PARAM="single_cpu_test=1 test_loop_count=10000 test_repeat_count=10"
+STRESS_PARAM="test_repeat_count=20"
+
+check_test_requirements()
+{
+ uid=$(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_HMM_DMIRROR=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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