hmm_range_fault() calls find_vma() and walk_page_range() in a loop. This is unnecessary duplication since walk_page_range() calls find_vma() in a loop already. Simplify hmm_range_fault() by defining a walk_test() callback function to filter unhandled vmas. This also fixes a bug where hmm_range_fault() was not checking start >= vma->vm_start before checking vma->vm_flags so hmm_range_fault() could return an error based on the wrong vma for the requested range. It also fixes a bug when the vma has no read access and the caller did not request a fault, there shouldn't be any error return code.

Signed-off-by: Ralph Campbell rcampbell@nvidia.com Cc: "Jérôme Glisse" jglisse@redhat.com Cc: Jason Gunthorpe jgg@mellanox.com Cc: Christoph Hellwig hch@lst.de --- mm/hmm.c | 121 ++++++++++++++++++++++++++----------------------------- 1 file changed, 58 insertions(+), 63 deletions(-)

diff --git a/mm/hmm.c b/mm/hmm.c index 9e9d3f4ea17c..d4984a08ed9b 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -65,18 +65,15 @@ static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, return -EFAULT; }

-static int hmm_pfns_bad(unsigned long addr, - unsigned long end, - struct mm_walk *walk) +static int hmm_pfns_fill(unsigned long addr, unsigned long end, + struct hmm_range *range, enum hmm_pfn_value_e value) { - struct hmm_vma_walk *hmm_vma_walk = walk->private; - struct hmm_range *range = hmm_vma_walk->range; uint64_t *pfns = range->pfns; unsigned long i;

i = (addr - range->start) >> PAGE_SHIFT; for (; addr < end; addr += PAGE_SIZE, i++) - pfns[i] = range->values[HMM_PFN_ERROR]; + pfns[i] = range->values[value];

return 0; } @@ -403,7 +400,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, } return 0; } else if (!pmd_present(pmd)) - return hmm_pfns_bad(start, end, walk); + return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);

if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { /* @@ -431,7 +428,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, * recover. */ if (pmd_bad(pmd)) - return hmm_pfns_bad(start, end, walk); + return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);

ptep = pte_offset_map(pmdp, addr); i = (addr - range->start) >> PAGE_SHIFT; @@ -589,13 +586,47 @@ static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, #define hmm_vma_walk_hugetlb_entry NULL #endif /* CONFIG_HUGETLB_PAGE */

-static void hmm_pfns_clear(struct hmm_range *range, - uint64_t *pfns, - unsigned long addr, - unsigned long end) +static int hmm_vma_walk_test(unsigned long start, unsigned long end, + struct mm_walk *walk) { - for (; addr < end; addr += PAGE_SIZE, pfns++) - *pfns = range->values[HMM_PFN_NONE]; + struct hmm_vma_walk *hmm_vma_walk = walk->private; + struct hmm_range *range = hmm_vma_walk->range; + struct vm_area_struct *vma = walk->vma; + + /* + * Skip vma ranges that don't have struct page backing them or + * map I/O devices directly. + */ + if (vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) + return -EFAULT; + + /* + * If the vma does not allow read access, then assume that it does not + * allow write access either. HMM does not support architectures + * that allow write without read. + */ + if (!(vma->vm_flags & VM_READ)) { + bool fault, write_fault; + + /* + * Check to see if a fault is requested for any page in the + * range. + */ + hmm_range_need_fault(hmm_vma_walk, range->pfns + + ((start - range->start) >> PAGE_SHIFT), + (end - start) >> PAGE_SHIFT, + 0, &fault, &write_fault); + if (fault || write_fault) + return -EFAULT; + + hmm_pfns_fill(start, end, range, HMM_PFN_NONE); + hmm_vma_walk->last = end; + + /* Skip this vma and continue processing the next vma. */ + return 1; + } + + return 0; }

static const struct mm_walk_ops hmm_walk_ops = { @@ -603,6 +634,7 @@ static const struct mm_walk_ops hmm_walk_ops = { .pmd_entry = hmm_vma_walk_pmd, .pte_hole = hmm_vma_walk_hole, .hugetlb_entry = hmm_vma_walk_hugetlb_entry, + .test_walk = hmm_vma_walk_test, };

/** @@ -635,11 +667,13 @@ static const struct mm_walk_ops hmm_walk_ops = { */ long hmm_range_fault(struct hmm_range *range, unsigned int flags) { - const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; - unsigned long start = range->start, end; - struct hmm_vma_walk hmm_vma_walk; + unsigned long start = range->start; + struct hmm_vma_walk hmm_vma_walk = { + .range = range, + .last = start, + .flags = flags, + }; struct mm_struct *mm = range->notifier->mm; - struct vm_area_struct *vma; int ret;

lockdep_assert_held(&mm->mmap_sem); @@ -648,52 +682,13 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags) /* If range is no longer valid force retry. */ if (mmu_range_check_retry(range->notifier, range->notifier_seq)) return -EBUSY; + ret = walk_page_range(mm, start, range->end, &hmm_walk_ops, + &hmm_vma_walk); + start = hmm_vma_walk.last; + } while (ret == -EBUSY);

- vma = find_vma(mm, start); - if (vma == NULL || (vma->vm_flags & device_vma)) - return -EFAULT; - - if (!(vma->vm_flags & VM_READ)) { - /* - * If vma do not allow read access, then assume that it - * does not allow write access, either. HMM does not - * support architecture that allow write without read. - */ - hmm_pfns_clear(range, range->pfns, - range->start, range->end); - return -EPERM; - } - - hmm_vma_walk.pgmap = NULL; - hmm_vma_walk.last = start; - hmm_vma_walk.flags = flags; - hmm_vma_walk.range = range; - end = min(range->end, vma->vm_end); - - walk_page_range(vma->vm_mm, start, end, &hmm_walk_ops, - &hmm_vma_walk); - - do { - ret = walk_page_range(vma->vm_mm, start, end, - &hmm_walk_ops, &hmm_vma_walk); - start = hmm_vma_walk.last; - - /* Keep trying while the range is valid. */ - } while (ret == -EBUSY && - !mmu_range_check_retry(range->notifier, - range->notifier_seq)); - - if (ret) { - unsigned long i; - - i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; - hmm_pfns_clear(range, &range->pfns[i], - hmm_vma_walk.last, range->end); - return ret; - } - start = end; - - } while (start < range->end); + if (ret) + return ret;

return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; }

Add self tests for HMM.

Signed-off-by: Ralph Campbell rcampbell@nvidia.com Signed-off-by: Jérôme Glisse jglisse@redhat.com --- MAINTAINERS | 3 + include/uapi/linux/test_hmm.h | 59 ++ lib/Kconfig.debug | 11 + lib/Makefile | 1 + lib/test_hmm.c | 1306 ++++++++++++++++++++++++ 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 | 1295 +++++++++++++++++++++++ tools/testing/selftests/vm/run_vmtests | 16 + tools/testing/selftests/vm/test_hmm.sh | 97 ++ 11 files changed, 2794 insertions(+) create mode 100644 include/uapi/linux/test_hmm.h 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 c6c34d04ce95..8d53e39df193 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7428,7 +7428,10 @@ 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/include/uapi/linux/test_hmm.h b/include/uapi/linux/test_hmm.h new file mode 100644 index 000000000000..8c5f70c160bf --- /dev/null +++ b/include/uapi/linux/test_hmm.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * This is a module to test the HMM (Heterogeneous Memory Management) API + * of the kernel. It allows a userspace program to expose its entire address + * space through the HMM test module device 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 device file */ +#define HMM_DMIRROR_READ _IOWR('H', 0x00, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_MIGRATE _IOWR('H', 0x02, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x03, struct hmm_dmirror_cmd) + +/* + * 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/lib/Kconfig.debug b/lib/Kconfig.debug index 93d97f9b0157..0354379d6cd0 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2057,6 +2057,17 @@ 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 c5892807e06f..6a9a0e564866 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -89,6 +89,7 @@ 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..9887a804d75a --- /dev/null +++ b/lib/test_hmm.c @@ -0,0 +1,1306 @@ +// 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. + * + * 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/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 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 attached to the open device file. + * Note that it might be shared after a fork(). + */ +struct dmirror { + struct mmu_notifier notifier; + struct dmirror_device *mdevice; + struct xarray pt; + struct mutex mutex; +}; + +struct dmirror_notifier { + struct mmu_range_notifier notifier; + struct dmirror *dmirror; +}; + +/* + * 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 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 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_store(&dmirror->pt, pfn, NULL, GFP_KERNEL); +} + +static int dmirror_invalidate_range_start(struct mmu_notifier *mn, + const struct mmu_notifier_range *update) +{ + struct dmirror *dmirror = container_of(mn, struct dmirror, notifier); + + if (mmu_notifier_range_blockable(update)) + mutex_lock(&dmirror->mutex); + else if (!mutex_trylock(&dmirror->mutex)) + return -EAGAIN; + + dmirror_do_update(dmirror, update->start, update->end); + mutex_unlock(&dmirror->mutex); + return 0; +} + +static void dmirror_free_notifier(struct mmu_notifier *mn) +{ + struct dmirror *dmirror = container_of(mn, struct dmirror, notifier); + + xa_destroy(&dmirror->pt); + kfree(dmirror); +} + +static const struct mmu_notifier_ops dmirror_mn_ops = { + .invalidate_range_start = dmirror_invalidate_range_start, + .free_notifier = dmirror_free_notifier, +}; + +/* + * 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 dmirror *dmirror; + int ret; + + /* Mirror this process address space */ + dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL); + if (dmirror == NULL) + goto err; + + dmirror->mdevice = mdevice; + mutex_init(&dmirror->mutex); + xa_init(&dmirror->pt); + + dmirror->notifier.ops = &dmirror_mn_ops; + ret = mmu_notifier_register(&dmirror->notifier, current->mm); + if (ret) + goto err_free; + + return dmirror; + +err_free: + kfree(dmirror); +err: + return NULL; +} + +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); + if (!dmirror) + return -ENOMEM; + + /* Only the first open registers the address space. */ + mutex_lock(&mdevice->devmem_lock); + if (filp->private_data) + goto err_busy; + filp->private_data = dmirror; + mutex_unlock(&mdevice->devmem_lock); + + return 0; + +err_busy: + mutex_unlock(&mdevice->devmem_lock); + mmu_notifier_put(&dmirror->notifier); + return -EBUSY; +} + +static int dmirror_fops_release(struct inode *inode, struct file *filp) +{ + struct dmirror *dmirror = filp->private_data; + + if (!dmirror) + return 0; + + filp->private_data = NULL; + mmu_notifier_put(&dmirror->notifier); + + 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, unsigned long start, + unsigned long end, struct hmm_range *range) +{ + unsigned long idx = (start - range->start) >> PAGE_SHIFT; + uint64_t *pfns = range->pfns + idx; + unsigned long pfn; + + for (pfn = start >> PAGE_SHIFT; pfn < (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_KERNEL); + if (xa_is_err(entry)) + return xa_err(entry); + } + + return 0; +} + +static bool dmirror_range_invalidate(struct mmu_range_notifier *mrn, + const struct mmu_notifier_range *range, + unsigned long cur_seq) +{ + struct dmirror_notifier *dn = + container_of(mrn, struct dmirror_notifier, notifier); + + /* + * Serializes the update to mrn->invalidate_seq done by caller and + * prevents invalidation from progressing while a device's page table + * is being updated. + */ + if (mmu_notifier_range_blockable(range)) + mutex_lock(&dn->dmirror->mutex); + else if (!mutex_trylock(&dn->dmirror->mutex)) + return false; + mmu_range_set_seq(mrn, cur_seq); + mutex_unlock(&dn->dmirror->mutex); + return true; +} + +static const struct mmu_range_notifier_ops dmirror_mrn_ops = { + .invalidate = dmirror_range_invalidate, +}; + +static int dmirror_range_fault(struct dmirror *dmirror, + struct hmm_range *range) +{ + struct mm_struct *mm = dmirror->notifier.mm; + struct dmirror_notifier notifier; + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + int ret; + + /* Since the mm is for the mirrored process, get a reference first. */ + if (!mmget_not_zero(mm)) + return 0; + + notifier.dmirror = dmirror; + notifier.notifier.ops = &dmirror_mrn_ops; + range->notifier = &notifier.notifier; + + ret = mmu_range_notifier_insert(&notifier.notifier, range->start, + range->end - range->start, mm); + if (ret) + return ret; + + while (true) { + long count; + + if (time_after(jiffies, timeout)) { + ret = -EBUSY; + goto out; + } + + range->notifier_seq = mmu_range_read_begin(range->notifier); + + down_read(&mm->mmap_sem); + 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_range_read_retry(range->notifier, + range->notifier_seq)) { + mutex_unlock(&dmirror->mutex); + continue; + } + break; + } + + ret = dmirror_do_fault(dmirror, range->start, range->end, range); + + mutex_unlock(&dmirror->mutex); +out: + mmu_range_notifier_remove(&notifier.notifier); + mmput(mm); + return ret; +} + +static int dmirror_fault(struct dmirror *dmirror, unsigned long start, + unsigned long end, bool write) +{ + struct mm_struct *mm = dmirror->notifier.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 = 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 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 = dmirror_bounce_copy_from(&bounce, cmd->ptr); + 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; + + /* Numa node ID doesn't matter for ZONE_DEVICE private pages. */ + ptr = memremap_pages(&devmem->pagemap, 0); + 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; + } +} + +struct dmirror_migrate { + struct hmm_dmirror_cmd *cmd; + const unsigned long *src; + const unsigned long *dst; + unsigned long start; +}; + +static int dmirror_do_migrate(struct dmirror *dmirror, unsigned long start, + unsigned long end, + struct dmirror_migrate *migrate) +{ + unsigned long idx = (start - migrate->start) >> PAGE_SHIFT; + const unsigned long *src = migrate->src + idx; + const unsigned long *dst = migrate->dst + idx; + unsigned long pfn; + + for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, + src++, dst++) { + struct page *page; + void *entry; + + if (!(*src & MIGRATE_PFN_MIGRATE)) + continue; + + page = migrate_pfn_to_page(*dst); + if (!page) + continue; + + /* + * Store the page that holds the data so the page table + * doesn't have to deal with ZONE_DEVICE private pages. + */ + entry = page->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_KERNEL); + if (xa_is_err(entry)) + return xa_err(entry); + } + + 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.src = args->src; + migrate.dst = args->dst; + migrate.start = args->start; + + /* Map the migrated pages into the device's page tables. */ + mutex_lock(&dmirror->mutex); + dmirror_do_migrate(dmirror, args->start, args->end, &migrate); + mutex_unlock(&dmirror->mutex); +} + +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->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; + + 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, cmd); + 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 = 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; + } + 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 int dmirror_range_snapshot(struct dmirror *dmirror, + struct hmm_range *range, + unsigned char *perm) +{ + struct mm_struct *mm = dmirror->notifier.mm; + struct dmirror_notifier notifier; + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + unsigned long i; + unsigned long n; + int ret; + + /* Since the mm is for the mirrored process, get a reference first. */ + if (!mmget_not_zero(mm)) + return 0; + + notifier.dmirror = dmirror; + notifier.notifier.ops = &dmirror_mrn_ops; + range->notifier = &notifier.notifier; + + ret = mmu_range_notifier_insert(&notifier.notifier, range->start, + range->end - range->start, mm); + if (ret) + return ret; + + while (true) { + long count; + + if (time_after(jiffies, timeout)) { + ret = -EBUSY; + goto out; + } + + range->notifier_seq = mmu_range_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_range_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_range_notifier_remove(&notifier.notifier); + mmput(mm); + return ret; +} + +static int dmirror_snapshot(struct dmirror *dmirror, + struct hmm_dmirror_cmd *cmd) +{ + struct mm_struct *mm = dmirror->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 = { + .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; + uptr = (void __user *)cmd->ptr; + + /* Since the mm is for the mirrored process, get a reference first. */ + if (!mmget_not_zero(mm)) + return -EINVAL; + + 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); + mmu_notifier_synchronize(); +} + +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 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..7fd96113575e 100644 --- a/tools/testing/selftests/vm/config +++ b/tools/testing/selftests/vm/config @@ -1,2 +1,4 @@ CONFIG_SYSVIPC=y CONFIG_USERFAULTFD=y +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..f1e530353bcd --- /dev/null +++ b/tools/testing/selftests/vm/hmm-tests.c @@ -0,0 +1,1295 @@ +// 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; + 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 | 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_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 $exitcode diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh new file mode 100755 index 000000000000..461e4a99a362 --- /dev/null +++ b/tools/testing/selftests/vm/test_hmm.sh @@ -0,0 +1,97 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) 2018 Uladzislau Rezki (Sony) urezki@gmail.com +# +# This is a test script for the kernel test driver to analyse vmalloc +# allocator. Therefore it is just a kernel module loader. You can specify +# and pass different parameters in order to: +# a) analyse performance of vmalloc allocations; +# b) stressing and stability check of vmalloc subsystem. + +TEST_NAME="test_hmm" +DRIVER="test_hmm" + +# 1 if fails +exitcode=1 + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +check_test_requirements() +{ + uid=$(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