From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/mm/hmm.c | 1529 +++++++++++++++-------------------------------------------
1 files changed, 390 insertions(+), 1,139 deletions(-)
diff --git a/kernel/mm/hmm.c b/kernel/mm/hmm.c
index c482c07..cbe9d0c 100644
--- a/kernel/mm/hmm.c
+++ b/kernel/mm/hmm.c
@@ -1,23 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
+ * Authors: Jérôme Glisse <jglisse@redhat.com>
*/
/*
* Refer to include/linux/hmm.h for information about heterogeneous memory
* management or HMM for short.
*/
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
#include <linux/hmm.h>
#include <linux/init.h>
#include <linux/rmap.h>
@@ -29,545 +20,300 @@
#include <linux/swapops.h>
#include <linux/hugetlb.h>
#include <linux/memremap.h>
+#include <linux/sched/mm.h>
#include <linux/jump_label.h>
+#include <linux/dma-mapping.h>
#include <linux/mmu_notifier.h>
#include <linux/memory_hotplug.h>
-
-#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-
-#if IS_ENABLED(CONFIG_HMM_MIRROR)
-static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
-
-/*
- * struct hmm - HMM per mm struct
- *
- * @mm: mm struct this HMM struct is bound to
- * @lock: lock protecting ranges list
- * @sequence: we track updates to the CPU page table with a sequence number
- * @ranges: list of range being snapshotted
- * @mirrors: list of mirrors for this mm
- * @mmu_notifier: mmu notifier to track updates to CPU page table
- * @mirrors_sem: read/write semaphore protecting the mirrors list
- */
-struct hmm {
- struct mm_struct *mm;
- spinlock_t lock;
- atomic_t sequence;
- struct list_head ranges;
- struct list_head mirrors;
- struct mmu_notifier mmu_notifier;
- struct rw_semaphore mirrors_sem;
-};
-
-/*
- * hmm_register - register HMM against an mm (HMM internal)
- *
- * @mm: mm struct to attach to
- *
- * This is not intended to be used directly by device drivers. It allocates an
- * HMM struct if mm does not have one, and initializes it.
- */
-static struct hmm *hmm_register(struct mm_struct *mm)
-{
- struct hmm *hmm = READ_ONCE(mm->hmm);
- bool cleanup = false;
-
- /*
- * The hmm struct can only be freed once the mm_struct goes away,
- * hence we should always have pre-allocated an new hmm struct
- * above.
- */
- if (hmm)
- return hmm;
-
- hmm = kmalloc(sizeof(*hmm), GFP_KERNEL);
- if (!hmm)
- return NULL;
- INIT_LIST_HEAD(&hmm->mirrors);
- init_rwsem(&hmm->mirrors_sem);
- atomic_set(&hmm->sequence, 0);
- hmm->mmu_notifier.ops = NULL;
- INIT_LIST_HEAD(&hmm->ranges);
- spin_lock_init(&hmm->lock);
- hmm->mm = mm;
-
- spin_lock(&mm->page_table_lock);
- if (!mm->hmm)
- mm->hmm = hmm;
- else
- cleanup = true;
- spin_unlock(&mm->page_table_lock);
-
- if (cleanup)
- goto error;
-
- /*
- * We should only get here if hold the mmap_sem in write mode ie on
- * registration of first mirror through hmm_mirror_register()
- */
- hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops;
- if (__mmu_notifier_register(&hmm->mmu_notifier, mm))
- goto error_mm;
-
- return mm->hmm;
-
-error_mm:
- spin_lock(&mm->page_table_lock);
- if (mm->hmm == hmm)
- mm->hmm = NULL;
- spin_unlock(&mm->page_table_lock);
-error:
- kfree(hmm);
- return NULL;
-}
-
-void hmm_mm_destroy(struct mm_struct *mm)
-{
- kfree(mm->hmm);
-}
-
-static void hmm_invalidate_range(struct hmm *hmm,
- enum hmm_update_type action,
- unsigned long start,
- unsigned long end)
-{
- struct hmm_mirror *mirror;
- struct hmm_range *range;
-
- spin_lock(&hmm->lock);
- list_for_each_entry(range, &hmm->ranges, list) {
- unsigned long addr, idx, npages;
-
- if (end < range->start || start >= range->end)
- continue;
-
- range->valid = false;
- addr = max(start, range->start);
- idx = (addr - range->start) >> PAGE_SHIFT;
- npages = (min(range->end, end) - addr) >> PAGE_SHIFT;
- memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages);
- }
- spin_unlock(&hmm->lock);
-
- down_read(&hmm->mirrors_sem);
- list_for_each_entry(mirror, &hmm->mirrors, list)
- mirror->ops->sync_cpu_device_pagetables(mirror, action,
- start, end);
- up_read(&hmm->mirrors_sem);
-}
-
-static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm)
-{
- struct hmm_mirror *mirror;
- struct hmm *hmm = mm->hmm;
-
- down_write(&hmm->mirrors_sem);
- mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror,
- list);
- while (mirror) {
- list_del_init(&mirror->list);
- if (mirror->ops->release) {
- /*
- * Drop mirrors_sem so callback can wait on any pending
- * work that might itself trigger mmu_notifier callback
- * and thus would deadlock with us.
- */
- up_write(&hmm->mirrors_sem);
- mirror->ops->release(mirror);
- down_write(&hmm->mirrors_sem);
- }
- mirror = list_first_entry_or_null(&hmm->mirrors,
- struct hmm_mirror, list);
- }
- up_write(&hmm->mirrors_sem);
-}
-
-static int hmm_invalidate_range_start(struct mmu_notifier *mn,
- struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- bool blockable)
-{
- struct hmm *hmm = mm->hmm;
-
- VM_BUG_ON(!hmm);
-
- atomic_inc(&hmm->sequence);
-
- return 0;
-}
-
-static void hmm_invalidate_range_end(struct mmu_notifier *mn,
- struct mm_struct *mm,
- unsigned long start,
- unsigned long end)
-{
- struct hmm *hmm = mm->hmm;
-
- VM_BUG_ON(!hmm);
-
- hmm_invalidate_range(mm->hmm, HMM_UPDATE_INVALIDATE, start, end);
-}
-
-static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
- .release = hmm_release,
- .invalidate_range_start = hmm_invalidate_range_start,
- .invalidate_range_end = hmm_invalidate_range_end,
-};
-
-/*
- * hmm_mirror_register() - register a mirror against an mm
- *
- * @mirror: new mirror struct to register
- * @mm: mm to register against
- *
- * To start mirroring a process address space, the device driver must register
- * an HMM mirror struct.
- *
- * THE mm->mmap_sem MUST BE HELD IN WRITE MODE !
- */
-int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
-{
- /* Sanity check */
- if (!mm || !mirror || !mirror->ops)
- return -EINVAL;
-
-again:
- mirror->hmm = hmm_register(mm);
- if (!mirror->hmm)
- return -ENOMEM;
-
- down_write(&mirror->hmm->mirrors_sem);
- if (mirror->hmm->mm == NULL) {
- /*
- * A racing hmm_mirror_unregister() is about to destroy the hmm
- * struct. Try again to allocate a new one.
- */
- up_write(&mirror->hmm->mirrors_sem);
- mirror->hmm = NULL;
- goto again;
- } else {
- list_add(&mirror->list, &mirror->hmm->mirrors);
- up_write(&mirror->hmm->mirrors_sem);
- }
-
- return 0;
-}
-EXPORT_SYMBOL(hmm_mirror_register);
-
-/*
- * hmm_mirror_unregister() - unregister a mirror
- *
- * @mirror: new mirror struct to register
- *
- * Stop mirroring a process address space, and cleanup.
- */
-void hmm_mirror_unregister(struct hmm_mirror *mirror)
-{
- bool should_unregister = false;
- struct mm_struct *mm;
- struct hmm *hmm;
-
- if (mirror->hmm == NULL)
- return;
-
- hmm = mirror->hmm;
- down_write(&hmm->mirrors_sem);
- list_del_init(&mirror->list);
- should_unregister = list_empty(&hmm->mirrors);
- mirror->hmm = NULL;
- mm = hmm->mm;
- hmm->mm = NULL;
- up_write(&hmm->mirrors_sem);
-
- if (!should_unregister || mm == NULL)
- return;
-
- mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm);
-
- spin_lock(&mm->page_table_lock);
- if (mm->hmm == hmm)
- mm->hmm = NULL;
- spin_unlock(&mm->page_table_lock);
-
- kfree(hmm);
-}
-EXPORT_SYMBOL(hmm_mirror_unregister);
struct hmm_vma_walk {
struct hmm_range *range;
unsigned long last;
- bool fault;
- bool block;
};
-static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
- bool write_fault, uint64_t *pfn)
+enum {
+ HMM_NEED_FAULT = 1 << 0,
+ HMM_NEED_WRITE_FAULT = 1 << 1,
+ HMM_NEED_ALL_BITS = HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT,
+};
+
+static int hmm_pfns_fill(unsigned long addr, unsigned long end,
+ struct hmm_range *range, unsigned long cpu_flags)
{
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
- struct hmm_vma_walk *hmm_vma_walk = walk->private;
- struct hmm_range *range = hmm_vma_walk->range;
- struct vm_area_struct *vma = walk->vma;
- vm_fault_t ret;
+ unsigned long i = (addr - range->start) >> PAGE_SHIFT;
- flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY;
- flags |= write_fault ? FAULT_FLAG_WRITE : 0;
- ret = handle_mm_fault(vma, addr, flags);
- if (ret & VM_FAULT_RETRY)
- return -EBUSY;
- if (ret & VM_FAULT_ERROR) {
- *pfn = range->values[HMM_PFN_ERROR];
- return -EFAULT;
- }
-
- return -EAGAIN;
-}
-
-static int hmm_pfns_bad(unsigned long addr,
- unsigned long end,
- struct mm_walk *walk)
-{
- 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];
-
+ range->hmm_pfns[i] = cpu_flags;
return 0;
}
/*
- * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s)
- * @start: range virtual start address (inclusive)
+ * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s)
+ * @addr: range virtual start address (inclusive)
* @end: range virtual end address (exclusive)
- * @fault: should we fault or not ?
- * @write_fault: write fault ?
+ * @required_fault: HMM_NEED_* flags
* @walk: mm_walk structure
- * Returns: 0 on success, -EAGAIN after page fault, or page fault error
+ * Return: -EBUSY after page fault, or page fault error
*
* This function will be called whenever pmd_none() or pte_none() returns true,
* or whenever there is no page directory covering the virtual address range.
*/
-static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end,
- bool fault, bool write_fault,
- struct mm_walk *walk)
+static int hmm_vma_fault(unsigned long addr, unsigned long end,
+ unsigned int required_fault, struct mm_walk *walk)
{
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;
+ struct vm_area_struct *vma = walk->vma;
+ unsigned int fault_flags = FAULT_FLAG_REMOTE;
+ WARN_ON_ONCE(!required_fault);
hmm_vma_walk->last = addr;
- i = (addr - range->start) >> PAGE_SHIFT;
- for (; addr < end; addr += PAGE_SIZE, i++) {
- pfns[i] = range->values[HMM_PFN_NONE];
- if (fault || write_fault) {
- int ret;
- ret = hmm_vma_do_fault(walk, addr, write_fault,
- &pfns[i]);
- if (ret != -EAGAIN)
- return ret;
- }
+ if (required_fault & HMM_NEED_WRITE_FAULT) {
+ if (!(vma->vm_flags & VM_WRITE))
+ return -EPERM;
+ fault_flags |= FAULT_FLAG_WRITE;
}
- return (fault || write_fault) ? -EAGAIN : 0;
+ for (; addr < end; addr += PAGE_SIZE)
+ if (handle_mm_fault(vma, addr, fault_flags, NULL) &
+ VM_FAULT_ERROR)
+ return -EFAULT;
+ return -EBUSY;
}
-static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
- uint64_t pfns, uint64_t cpu_flags,
- bool *fault, bool *write_fault)
+static unsigned int hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
+ unsigned long pfn_req_flags,
+ unsigned long cpu_flags)
{
struct hmm_range *range = hmm_vma_walk->range;
- *fault = *write_fault = false;
- if (!hmm_vma_walk->fault)
- return;
+ /*
+ * So we not only consider the individual per page request we also
+ * consider the default flags requested for the range. The API can
+ * be used 2 ways. The first one where the HMM user coalesces
+ * multiple page faults into one request and sets flags per pfn for
+ * those faults. The second one where the HMM user wants to pre-
+ * fault a range with specific flags. For the latter one it is a
+ * waste to have the user pre-fill the pfn arrays with a default
+ * flags value.
+ */
+ pfn_req_flags &= range->pfn_flags_mask;
+ pfn_req_flags |= range->default_flags;
/* We aren't ask to do anything ... */
- if (!(pfns & range->flags[HMM_PFN_VALID]))
- return;
- /* If this is device memory than only fault if explicitly requested */
- if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) {
- /* Do we fault on device memory ? */
- if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) {
- *write_fault = pfns & range->flags[HMM_PFN_WRITE];
- *fault = true;
- }
- return;
- }
+ if (!(pfn_req_flags & HMM_PFN_REQ_FAULT))
+ return 0;
+
+ /* Need to write fault ? */
+ if ((pfn_req_flags & HMM_PFN_REQ_WRITE) &&
+ !(cpu_flags & HMM_PFN_WRITE))
+ return HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT;
/* If CPU page table is not valid then we need to fault */
- *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]);
- /* Need to write fault ? */
- if ((pfns & range->flags[HMM_PFN_WRITE]) &&
- !(cpu_flags & range->flags[HMM_PFN_WRITE])) {
- *write_fault = true;
- *fault = true;
- }
+ if (!(cpu_flags & HMM_PFN_VALID))
+ return HMM_NEED_FAULT;
+ return 0;
}
-static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
- const uint64_t *pfns, unsigned long npages,
- uint64_t cpu_flags, bool *fault,
- bool *write_fault)
+static unsigned int
+hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
+ const unsigned long hmm_pfns[], unsigned long npages,
+ unsigned long cpu_flags)
{
+ struct hmm_range *range = hmm_vma_walk->range;
+ unsigned int required_fault = 0;
unsigned long i;
- if (!hmm_vma_walk->fault) {
- *fault = *write_fault = false;
- return;
- }
+ /*
+ * If the default flags do not request to fault pages, and the mask does
+ * not allow for individual pages to be faulted, then
+ * hmm_pte_need_fault() will always return 0.
+ */
+ if (!((range->default_flags | range->pfn_flags_mask) &
+ HMM_PFN_REQ_FAULT))
+ return 0;
for (i = 0; i < npages; ++i) {
- hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags,
- fault, write_fault);
- if ((*fault) || (*write_fault))
- return;
+ required_fault |= hmm_pte_need_fault(hmm_vma_walk, hmm_pfns[i],
+ cpu_flags);
+ if (required_fault == HMM_NEED_ALL_BITS)
+ return required_fault;
}
+ return required_fault;
}
static int hmm_vma_walk_hole(unsigned long addr, unsigned long end,
- struct mm_walk *walk)
+ __always_unused int depth, struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- bool fault, write_fault;
+ unsigned int required_fault;
unsigned long i, npages;
- uint64_t *pfns;
+ unsigned long *hmm_pfns;
i = (addr - range->start) >> PAGE_SHIFT;
npages = (end - addr) >> PAGE_SHIFT;
- pfns = &range->pfns[i];
- hmm_range_need_fault(hmm_vma_walk, pfns, npages,
- 0, &fault, &write_fault);
- return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk);
+ hmm_pfns = &range->hmm_pfns[i];
+ required_fault =
+ hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0);
+ if (!walk->vma) {
+ if (required_fault)
+ return -EFAULT;
+ return hmm_pfns_fill(addr, end, range, HMM_PFN_ERROR);
+ }
+ if (required_fault)
+ return hmm_vma_fault(addr, end, required_fault, walk);
+ return hmm_pfns_fill(addr, end, range, 0);
}
-static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd)
+static inline unsigned long hmm_pfn_flags_order(unsigned long order)
+{
+ return order << HMM_PFN_ORDER_SHIFT;
+}
+
+static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
+ pmd_t pmd)
{
if (pmd_protnone(pmd))
return 0;
- return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] |
- range->flags[HMM_PFN_WRITE] :
- range->flags[HMM_PFN_VALID];
+ return (pmd_write(pmd) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
+ HMM_PFN_VALID) |
+ hmm_pfn_flags_order(PMD_SHIFT - PAGE_SHIFT);
}
-static int hmm_vma_handle_pmd(struct mm_walk *walk,
- unsigned long addr,
- unsigned long end,
- uint64_t *pfns,
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
+ unsigned long end, unsigned long hmm_pfns[],
pmd_t pmd)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned long pfn, npages, i;
- bool fault, write_fault;
- uint64_t cpu_flags;
+ unsigned int required_fault;
+ unsigned long cpu_flags;
npages = (end - addr) >> PAGE_SHIFT;
cpu_flags = pmd_to_hmm_pfn_flags(range, pmd);
- hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags,
- &fault, &write_fault);
+ required_fault =
+ hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, cpu_flags);
+ if (required_fault)
+ return hmm_vma_fault(addr, end, required_fault, walk);
- if (pmd_protnone(pmd) || fault || write_fault)
- return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk);
-
- pfn = pmd_pfn(pmd) + pte_index(addr);
+ pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
- pfns[i] = hmm_pfn_from_pfn(range, pfn) | cpu_flags;
- hmm_vma_walk->last = end;
+ hmm_pfns[i] = pfn | cpu_flags;
return 0;
}
+#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+/* stub to allow the code below to compile */
+int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
+ unsigned long end, unsigned long hmm_pfns[], pmd_t pmd);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte)
+static inline bool hmm_is_device_private_entry(struct hmm_range *range,
+ swp_entry_t entry)
{
- if (pte_none(pte) || !pte_present(pte))
+ return is_device_private_entry(entry) &&
+ device_private_entry_to_page(entry)->pgmap->owner ==
+ range->dev_private_owner;
+}
+
+static inline unsigned long pte_to_hmm_pfn_flags(struct hmm_range *range,
+ pte_t pte)
+{
+ if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte))
return 0;
- return pte_write(pte) ? range->flags[HMM_PFN_VALID] |
- range->flags[HMM_PFN_WRITE] :
- range->flags[HMM_PFN_VALID];
+ return pte_write(pte) ? (HMM_PFN_VALID | HMM_PFN_WRITE) : HMM_PFN_VALID;
}
static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
unsigned long end, pmd_t *pmdp, pte_t *ptep,
- uint64_t *pfn)
+ unsigned long *hmm_pfn)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- struct vm_area_struct *vma = walk->vma;
- bool fault, write_fault;
- uint64_t cpu_flags;
+ unsigned int required_fault;
+ unsigned long cpu_flags;
pte_t pte = *ptep;
- uint64_t orig_pfn = *pfn;
-
- *pfn = range->values[HMM_PFN_NONE];
- cpu_flags = pte_to_hmm_pfn_flags(range, pte);
- hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags,
- &fault, &write_fault);
+ uint64_t pfn_req_flags = *hmm_pfn;
if (pte_none(pte)) {
- if (fault || write_fault)
+ required_fault =
+ hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
+ if (required_fault)
goto fault;
+ *hmm_pfn = 0;
return 0;
}
if (!pte_present(pte)) {
swp_entry_t entry = pte_to_swp_entry(pte);
- if (!non_swap_entry(entry)) {
- if (fault || write_fault)
- goto fault;
+ /*
+ * Never fault in device private pages, but just report
+ * the PFN even if not present.
+ */
+ if (hmm_is_device_private_entry(range, entry)) {
+ cpu_flags = HMM_PFN_VALID;
+ if (is_write_device_private_entry(entry))
+ cpu_flags |= HMM_PFN_WRITE;
+ *hmm_pfn = device_private_entry_to_pfn(entry) |
+ cpu_flags;
return 0;
}
- /*
- * This is a special swap entry, ignore migration, use
- * device and report anything else as error.
- */
- if (is_device_private_entry(entry)) {
- cpu_flags = range->flags[HMM_PFN_VALID] |
- range->flags[HMM_PFN_DEVICE_PRIVATE];
- cpu_flags |= is_write_device_private_entry(entry) ?
- range->flags[HMM_PFN_WRITE] : 0;
- hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags,
- &fault, &write_fault);
- if (fault || write_fault)
- goto fault;
- *pfn = hmm_pfn_from_pfn(range, swp_offset(entry));
- *pfn |= cpu_flags;
+ required_fault =
+ hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
+ if (!required_fault) {
+ *hmm_pfn = 0;
return 0;
}
+
+ if (!non_swap_entry(entry))
+ goto fault;
if (is_migration_entry(entry)) {
- if (fault || write_fault) {
- pte_unmap(ptep);
- hmm_vma_walk->last = addr;
- migration_entry_wait(vma->vm_mm,
- pmdp, addr);
- return -EAGAIN;
- }
- return 0;
+ pte_unmap(ptep);
+ hmm_vma_walk->last = addr;
+ migration_entry_wait(walk->mm, pmdp, addr);
+ return -EBUSY;
}
/* Report error for everything else */
- *pfn = range->values[HMM_PFN_ERROR];
+ pte_unmap(ptep);
return -EFAULT;
}
- if (fault || write_fault)
+ cpu_flags = pte_to_hmm_pfn_flags(range, pte);
+ required_fault =
+ hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
+ if (required_fault)
goto fault;
- *pfn = hmm_pfn_from_pfn(range, pte_pfn(pte)) | cpu_flags;
+ /*
+ * Bypass devmap pte such as DAX page when all pfn requested
+ * flags(pfn_req_flags) are fulfilled.
+ * Since each architecture defines a struct page for the zero page, just
+ * fall through and treat it like a normal page.
+ */
+ if (!vm_normal_page(walk->vma, addr, pte) &&
+ !pte_devmap(pte) &&
+ !is_zero_pfn(pte_pfn(pte))) {
+ if (hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0)) {
+ pte_unmap(ptep);
+ return -EFAULT;
+ }
+ *hmm_pfn = HMM_PFN_ERROR;
+ return 0;
+ }
+
+ *hmm_pfn = pte_pfn(pte) | cpu_flags;
return 0;
fault:
pte_unmap(ptep);
/* Fault any virtual address we were asked to fault */
- return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk);
+ return hmm_vma_fault(addr, end, required_fault, walk);
}
static int hmm_vma_walk_pmd(pmd_t *pmdp,
@@ -577,28 +323,40 @@
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- uint64_t *pfns = range->pfns;
- unsigned long addr = start, i;
+ unsigned long *hmm_pfns =
+ &range->hmm_pfns[(start - range->start) >> PAGE_SHIFT];
+ unsigned long npages = (end - start) >> PAGE_SHIFT;
+ unsigned long addr = start;
pte_t *ptep;
-
- i = (addr - range->start) >> PAGE_SHIFT;
+ pmd_t pmd;
again:
- if (pmd_none(*pmdp))
- return hmm_vma_walk_hole(start, end, walk);
+ pmd = READ_ONCE(*pmdp);
+ if (pmd_none(pmd))
+ return hmm_vma_walk_hole(start, end, -1, walk);
- if (pmd_huge(*pmdp) && (range->vma->vm_flags & VM_HUGETLB))
- return hmm_pfns_bad(start, end, walk);
+ if (thp_migration_supported() && is_pmd_migration_entry(pmd)) {
+ if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0)) {
+ hmm_vma_walk->last = addr;
+ pmd_migration_entry_wait(walk->mm, pmdp);
+ return -EBUSY;
+ }
+ return hmm_pfns_fill(start, end, range, 0);
+ }
- if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) {
- pmd_t pmd;
+ if (!pmd_present(pmd)) {
+ if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
+ return -EFAULT;
+ return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
+ }
+ if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) {
/*
- * No need to take pmd_lock here, even if some other threads
+ * No need to take pmd_lock here, even if some other thread
* is splitting the huge pmd we will get that event through
* mmu_notifier callback.
*
- * So just read pmd value and check again its a transparent
+ * So just read pmd value and check again it's a transparent
* huge or device mapping one and compute corresponding pfn
* values.
*/
@@ -607,742 +365,235 @@
if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
goto again;
- return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd);
+ return hmm_vma_handle_pmd(walk, addr, end, hmm_pfns, pmd);
}
- if (pmd_bad(*pmdp))
- return hmm_pfns_bad(start, end, walk);
+ /*
+ * We have handled all the valid cases above ie either none, migration,
+ * huge or transparent huge. At this point either it is a valid pmd
+ * entry pointing to pte directory or it is a bad pmd that will not
+ * recover.
+ */
+ if (pmd_bad(pmd)) {
+ if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
+ return -EFAULT;
+ return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
+ }
ptep = pte_offset_map(pmdp, addr);
- for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
+ for (; addr < end; addr += PAGE_SIZE, ptep++, hmm_pfns++) {
int r;
- r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]);
+ r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, hmm_pfns);
if (r) {
- /* hmm_vma_handle_pte() did unmap pte directory */
- hmm_vma_walk->last = addr;
+ /* hmm_vma_handle_pte() did pte_unmap() */
return r;
}
}
pte_unmap(ptep - 1);
-
- hmm_vma_walk->last = addr;
return 0;
}
-static void hmm_pfns_clear(struct hmm_range *range,
- uint64_t *pfns,
- unsigned long addr,
- unsigned long end)
+#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \
+ defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
+static inline unsigned long pud_to_hmm_pfn_flags(struct hmm_range *range,
+ pud_t pud)
{
- for (; addr < end; addr += PAGE_SIZE, pfns++)
- *pfns = range->values[HMM_PFN_NONE];
+ if (!pud_present(pud))
+ return 0;
+ return (pud_write(pud) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
+ HMM_PFN_VALID) |
+ hmm_pfn_flags_order(PUD_SHIFT - PAGE_SHIFT);
}
-static void hmm_pfns_special(struct hmm_range *range)
+static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
+ struct mm_walk *walk)
{
- unsigned long addr = range->start, i = 0;
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ struct hmm_range *range = hmm_vma_walk->range;
+ unsigned long addr = start;
+ pud_t pud;
+ int ret = 0;
+ spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma);
- for (; addr < range->end; addr += PAGE_SIZE, i++)
- range->pfns[i] = range->values[HMM_PFN_SPECIAL];
+ if (!ptl)
+ return 0;
+
+ /* Normally we don't want to split the huge page */
+ walk->action = ACTION_CONTINUE;
+
+ pud = READ_ONCE(*pudp);
+ if (pud_none(pud)) {
+ spin_unlock(ptl);
+ return hmm_vma_walk_hole(start, end, -1, walk);
+ }
+
+ if (pud_huge(pud) && pud_devmap(pud)) {
+ unsigned long i, npages, pfn;
+ unsigned int required_fault;
+ unsigned long *hmm_pfns;
+ unsigned long cpu_flags;
+
+ if (!pud_present(pud)) {
+ spin_unlock(ptl);
+ return hmm_vma_walk_hole(start, end, -1, walk);
+ }
+
+ i = (addr - range->start) >> PAGE_SHIFT;
+ npages = (end - addr) >> PAGE_SHIFT;
+ hmm_pfns = &range->hmm_pfns[i];
+
+ cpu_flags = pud_to_hmm_pfn_flags(range, pud);
+ required_fault = hmm_range_need_fault(hmm_vma_walk, hmm_pfns,
+ npages, cpu_flags);
+ if (required_fault) {
+ spin_unlock(ptl);
+ return hmm_vma_fault(addr, end, required_fault, walk);
+ }
+
+ pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
+ for (i = 0; i < npages; ++i, ++pfn)
+ hmm_pfns[i] = pfn | cpu_flags;
+ goto out_unlock;
+ }
+
+ /* Ask for the PUD to be split */
+ walk->action = ACTION_SUBTREE;
+
+out_unlock:
+ spin_unlock(ptl);
+ return ret;
}
+#else
+#define hmm_vma_walk_pud NULL
+#endif
-/*
- * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
- * @range: range being snapshotted
- * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
- * vma permission, 0 success
- *
- * This snapshots the CPU page table for a range of virtual addresses. Snapshot
- * validity is tracked by range struct. See hmm_vma_range_done() for further
- * information.
- *
- * The range struct is initialized here. It tracks the CPU page table, but only
- * if the function returns success (0), in which case the caller must then call
- * hmm_vma_range_done() to stop CPU page table update tracking on this range.
- *
- * NOT CALLING hmm_vma_range_done() IF FUNCTION RETURNS 0 WILL LEAD TO SERIOUS
- * MEMORY CORRUPTION ! YOU HAVE BEEN WARNED !
- */
-int hmm_vma_get_pfns(struct hmm_range *range)
+#ifdef CONFIG_HUGETLB_PAGE
+static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
+ unsigned long start, unsigned long end,
+ struct mm_walk *walk)
{
- struct vm_area_struct *vma = range->vma;
- struct hmm_vma_walk hmm_vma_walk;
- struct mm_walk mm_walk;
- struct hmm *hmm;
+ unsigned long addr = start, i, pfn;
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ struct hmm_range *range = hmm_vma_walk->range;
+ struct vm_area_struct *vma = walk->vma;
+ unsigned int required_fault;
+ unsigned long pfn_req_flags;
+ unsigned long cpu_flags;
+ spinlock_t *ptl;
+ pte_t entry;
- /* Sanity check, this really should not happen ! */
- if (range->start < vma->vm_start || range->start >= vma->vm_end)
- return -EINVAL;
- if (range->end < vma->vm_start || range->end > vma->vm_end)
- return -EINVAL;
+ ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte);
+ entry = huge_ptep_get(pte);
- hmm = hmm_register(vma->vm_mm);
- if (!hmm)
- return -ENOMEM;
- /* Caller must have registered a mirror, via hmm_mirror_register() ! */
- if (!hmm->mmu_notifier.ops)
- return -EINVAL;
-
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) ||
- vma_is_dax(vma)) {
- hmm_pfns_special(range);
- return -EINVAL;
+ i = (start - range->start) >> PAGE_SHIFT;
+ pfn_req_flags = range->hmm_pfns[i];
+ cpu_flags = pte_to_hmm_pfn_flags(range, entry) |
+ hmm_pfn_flags_order(huge_page_order(hstate_vma(vma)));
+ required_fault =
+ hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
+ if (required_fault) {
+ spin_unlock(ptl);
+ return hmm_vma_fault(addr, end, required_fault, walk);
}
- if (!(vma->vm_flags & VM_READ)) {
- /*
- * If vma do not allow read access, then assume that it does
- * not allow write access, either. Architecture that allow
- * write without read access are not supported by HMM, because
- * operations such has atomic access would not work.
- */
- hmm_pfns_clear(range, range->pfns, range->start, range->end);
- return -EPERM;
- }
+ pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT);
+ for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
+ range->hmm_pfns[i] = pfn | cpu_flags;
- /* Initialize range to track CPU page table update */
- spin_lock(&hmm->lock);
- range->valid = true;
- list_add_rcu(&range->list, &hmm->ranges);
- spin_unlock(&hmm->lock);
-
- hmm_vma_walk.fault = false;
- hmm_vma_walk.range = range;
- mm_walk.private = &hmm_vma_walk;
-
- mm_walk.vma = vma;
- mm_walk.mm = vma->vm_mm;
- mm_walk.pte_entry = NULL;
- mm_walk.test_walk = NULL;
- mm_walk.hugetlb_entry = NULL;
- mm_walk.pmd_entry = hmm_vma_walk_pmd;
- mm_walk.pte_hole = hmm_vma_walk_hole;
-
- walk_page_range(range->start, range->end, &mm_walk);
+ spin_unlock(ptl);
return 0;
}
-EXPORT_SYMBOL(hmm_vma_get_pfns);
+#else
+#define hmm_vma_walk_hugetlb_entry NULL
+#endif /* CONFIG_HUGETLB_PAGE */
-/*
- * hmm_vma_range_done() - stop tracking change to CPU page table over a range
- * @range: range being tracked
- * Returns: false if range data has been invalidated, true otherwise
- *
- * Range struct is used to track updates to the CPU page table after a call to
- * either hmm_vma_get_pfns() or hmm_vma_fault(). Once the device driver is done
- * using the data, or wants to lock updates to the data it got from those
- * functions, it must call the hmm_vma_range_done() function, which will then
- * stop tracking CPU page table updates.
- *
- * Note that device driver must still implement general CPU page table update
- * tracking either by using hmm_mirror (see hmm_mirror_register()) or by using
- * the mmu_notifier API directly.
- *
- * CPU page table update tracking done through hmm_range is only temporary and
- * to be used while trying to duplicate CPU page table contents for a range of
- * virtual addresses.
- *
- * There are two ways to use this :
- * again:
- * hmm_vma_get_pfns(range); or hmm_vma_fault(...);
- * trans = device_build_page_table_update_transaction(pfns);
- * device_page_table_lock();
- * if (!hmm_vma_range_done(range)) {
- * device_page_table_unlock();
- * goto again;
- * }
- * device_commit_transaction(trans);
- * device_page_table_unlock();
- *
- * Or:
- * hmm_vma_get_pfns(range); or hmm_vma_fault(...);
- * device_page_table_lock();
- * hmm_vma_range_done(range);
- * device_update_page_table(range->pfns);
- * device_page_table_unlock();
- */
-bool hmm_vma_range_done(struct hmm_range *range)
+static int hmm_vma_walk_test(unsigned long start, unsigned long end,
+ struct mm_walk *walk)
{
- unsigned long npages = (range->end - range->start) >> PAGE_SHIFT;
- struct hmm *hmm;
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ struct hmm_range *range = hmm_vma_walk->range;
+ struct vm_area_struct *vma = walk->vma;
- if (range->end <= range->start) {
- BUG();
- return false;
- }
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)) &&
+ vma->vm_flags & VM_READ)
+ return 0;
- hmm = hmm_register(range->vma->vm_mm);
- if (!hmm) {
- memset(range->pfns, 0, sizeof(*range->pfns) * npages);
- return false;
- }
+ /*
+ * vma ranges that don't have struct page backing them or map I/O
+ * devices directly cannot be handled by hmm_range_fault().
+ *
+ * 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 a fault is requested for an unsupported range then it is a hard
+ * failure.
+ */
+ if (hmm_range_need_fault(hmm_vma_walk,
+ range->hmm_pfns +
+ ((start - range->start) >> PAGE_SHIFT),
+ (end - start) >> PAGE_SHIFT, 0))
+ return -EFAULT;
- spin_lock(&hmm->lock);
- list_del_rcu(&range->list);
- spin_unlock(&hmm->lock);
+ hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
- return range->valid;
+ /* Skip this vma and continue processing the next vma. */
+ return 1;
}
-EXPORT_SYMBOL(hmm_vma_range_done);
-/*
- * hmm_vma_fault() - try to fault some address in a virtual address range
- * @range: range being faulted
- * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
- * Returns: 0 success, error otherwise (-EAGAIN means mmap_sem have been drop)
+static const struct mm_walk_ops hmm_walk_ops = {
+ .pud_entry = hmm_vma_walk_pud,
+ .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,
+};
+
+/**
+ * hmm_range_fault - try to fault some address in a virtual address range
+ * @range: argument structure
*
- * This is similar to a regular CPU page fault except that it will not trigger
- * any memory migration if the memory being faulted is not accessible by CPUs.
+ * Returns 0 on success or one of the following error codes:
*
- * On error, for one virtual address in the range, the function will mark the
- * corresponding HMM pfn entry with an error flag.
+ * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma
+ * (e.g., device file vma).
+ * -ENOMEM: Out of memory.
+ * -EPERM: Invalid permission (e.g., asking for write and range is read
+ * only).
+ * -EBUSY: The range has been invalidated and the caller needs to wait for
+ * the invalidation to finish.
+ * -EFAULT: A page was requested to be valid and could not be made valid
+ * ie it has no backing VMA or it is illegal to access
*
- * Expected use pattern:
- * retry:
- * down_read(&mm->mmap_sem);
- * // Find vma and address device wants to fault, initialize hmm_pfn_t
- * // array accordingly
- * ret = hmm_vma_fault(range, write, block);
- * switch (ret) {
- * case -EAGAIN:
- * hmm_vma_range_done(range);
- * // You might want to rate limit or yield to play nicely, you may
- * // also commit any valid pfn in the array assuming that you are
- * // getting true from hmm_vma_range_monitor_end()
- * goto retry;
- * case 0:
- * break;
- * case -ENOMEM:
- * case -EINVAL:
- * case -EPERM:
- * default:
- * // Handle error !
- * up_read(&mm->mmap_sem)
- * return;
- * }
- * // Take device driver lock that serialize device page table update
- * driver_lock_device_page_table_update();
- * hmm_vma_range_done(range);
- * // Commit pfns we got from hmm_vma_fault()
- * driver_unlock_device_page_table_update();
- * up_read(&mm->mmap_sem)
- *
- * YOU MUST CALL hmm_vma_range_done() AFTER THIS FUNCTION RETURN SUCCESS (0)
- * BEFORE FREEING THE range struct OR YOU WILL HAVE SERIOUS MEMORY CORRUPTION !
- *
- * YOU HAVE BEEN WARNED !
+ * This is similar to get_user_pages(), except that it can read the page tables
+ * without mutating them (ie causing faults).
*/
-int hmm_vma_fault(struct hmm_range *range, bool block)
+int hmm_range_fault(struct hmm_range *range)
{
- struct vm_area_struct *vma = range->vma;
- unsigned long start = range->start;
- struct hmm_vma_walk hmm_vma_walk;
- struct mm_walk mm_walk;
- struct hmm *hmm;
+ struct hmm_vma_walk hmm_vma_walk = {
+ .range = range,
+ .last = range->start,
+ };
+ struct mm_struct *mm = range->notifier->mm;
int ret;
- /* Sanity check, this really should not happen ! */
- if (range->start < vma->vm_start || range->start >= vma->vm_end)
- return -EINVAL;
- if (range->end < vma->vm_start || range->end > vma->vm_end)
- return -EINVAL;
-
- hmm = hmm_register(vma->vm_mm);
- if (!hmm) {
- hmm_pfns_clear(range, range->pfns, range->start, range->end);
- return -ENOMEM;
- }
- /* Caller must have registered a mirror using hmm_mirror_register() */
- if (!hmm->mmu_notifier.ops)
- return -EINVAL;
-
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) ||
- vma_is_dax(vma)) {
- hmm_pfns_special(range);
- return -EINVAL;
- }
-
- if (!(vma->vm_flags & VM_READ)) {
- /*
- * If vma do not allow read access, then assume that it does
- * not allow write access, either. Architecture that allow
- * write without read access are not supported by HMM, because
- * operations such has atomic access would not work.
- */
- hmm_pfns_clear(range, range->pfns, range->start, range->end);
- return -EPERM;
- }
-
- /* Initialize range to track CPU page table update */
- spin_lock(&hmm->lock);
- range->valid = true;
- list_add_rcu(&range->list, &hmm->ranges);
- spin_unlock(&hmm->lock);
-
- hmm_vma_walk.fault = true;
- hmm_vma_walk.block = block;
- hmm_vma_walk.range = range;
- mm_walk.private = &hmm_vma_walk;
- hmm_vma_walk.last = range->start;
-
- mm_walk.vma = vma;
- mm_walk.mm = vma->vm_mm;
- mm_walk.pte_entry = NULL;
- mm_walk.test_walk = NULL;
- mm_walk.hugetlb_entry = NULL;
- mm_walk.pmd_entry = hmm_vma_walk_pmd;
- mm_walk.pte_hole = hmm_vma_walk_hole;
+ mmap_assert_locked(mm);
do {
- ret = walk_page_range(start, range->end, &mm_walk);
- start = hmm_vma_walk.last;
- } while (ret == -EAGAIN);
-
- 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);
- hmm_vma_range_done(range);
- }
+ /* If range is no longer valid force retry. */
+ if (mmu_interval_check_retry(range->notifier,
+ range->notifier_seq))
+ return -EBUSY;
+ ret = walk_page_range(mm, hmm_vma_walk.last, range->end,
+ &hmm_walk_ops, &hmm_vma_walk);
+ /*
+ * When -EBUSY is returned the loop restarts with
+ * hmm_vma_walk.last set to an address that has not been stored
+ * in pfns. All entries < last in the pfn array are set to their
+ * output, and all >= are still at their input values.
+ */
+ } while (ret == -EBUSY);
return ret;
}
-EXPORT_SYMBOL(hmm_vma_fault);
-#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
-
-
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
-struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
- unsigned long addr)
-{
- struct page *page;
-
- page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
- if (!page)
- return NULL;
- lock_page(page);
- return page;
-}
-EXPORT_SYMBOL(hmm_vma_alloc_locked_page);
-
-
-static void hmm_devmem_ref_release(struct percpu_ref *ref)
-{
- struct hmm_devmem *devmem;
-
- devmem = container_of(ref, struct hmm_devmem, ref);
- complete(&devmem->completion);
-}
-
-static void hmm_devmem_ref_exit(void *data)
-{
- struct percpu_ref *ref = data;
- struct hmm_devmem *devmem;
-
- devmem = container_of(ref, struct hmm_devmem, ref);
- percpu_ref_exit(ref);
-}
-
-static void hmm_devmem_ref_kill(void *data)
-{
- struct percpu_ref *ref = data;
- struct hmm_devmem *devmem;
-
- devmem = container_of(ref, struct hmm_devmem, ref);
- percpu_ref_kill(ref);
- wait_for_completion(&devmem->completion);
-}
-
-static int hmm_devmem_fault(struct vm_area_struct *vma,
- unsigned long addr,
- const struct page *page,
- unsigned int flags,
- pmd_t *pmdp)
-{
- struct hmm_devmem *devmem = page->pgmap->data;
-
- return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp);
-}
-
-static void hmm_devmem_free(struct page *page, void *data)
-{
- struct hmm_devmem *devmem = data;
-
- page->mapping = NULL;
-
- devmem->ops->free(devmem, page);
-}
-
-static DEFINE_MUTEX(hmm_devmem_lock);
-static RADIX_TREE(hmm_devmem_radix, GFP_KERNEL);
-
-static void hmm_devmem_radix_release(struct resource *resource)
-{
- resource_size_t key;
-
- mutex_lock(&hmm_devmem_lock);
- for (key = resource->start;
- key <= resource->end;
- key += PA_SECTION_SIZE)
- radix_tree_delete(&hmm_devmem_radix, key >> PA_SECTION_SHIFT);
- mutex_unlock(&hmm_devmem_lock);
-}
-
-static void hmm_devmem_release(void *data)
-{
- struct hmm_devmem *devmem = data;
- struct resource *resource = devmem->resource;
- unsigned long start_pfn, npages;
- struct page *page;
- int nid;
-
- /* pages are dead and unused, undo the arch mapping */
- start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT;
- npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT;
-
- page = pfn_to_page(start_pfn);
- nid = page_to_nid(page);
-
- mem_hotplug_begin();
- if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY)
- __remove_pages(start_pfn, npages, NULL);
- else
- arch_remove_memory(nid, start_pfn << PAGE_SHIFT,
- npages << PAGE_SHIFT, NULL);
- mem_hotplug_done();
-
- hmm_devmem_radix_release(resource);
-}
-
-static int hmm_devmem_pages_create(struct hmm_devmem *devmem)
-{
- resource_size_t key, align_start, align_size, align_end;
- struct device *device = devmem->device;
- int ret, nid, is_ram;
- unsigned long pfn;
-
- align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1);
- align_size = ALIGN(devmem->resource->start +
- resource_size(devmem->resource),
- PA_SECTION_SIZE) - align_start;
-
- is_ram = region_intersects(align_start, align_size,
- IORESOURCE_SYSTEM_RAM,
- IORES_DESC_NONE);
- if (is_ram == REGION_MIXED) {
- WARN_ONCE(1, "%s attempted on mixed region %pr\n",
- __func__, devmem->resource);
- return -ENXIO;
- }
- if (is_ram == REGION_INTERSECTS)
- return -ENXIO;
-
- if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY)
- devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
- else
- devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
-
- devmem->pagemap.res = *devmem->resource;
- devmem->pagemap.page_fault = hmm_devmem_fault;
- devmem->pagemap.page_free = hmm_devmem_free;
- devmem->pagemap.dev = devmem->device;
- devmem->pagemap.ref = &devmem->ref;
- devmem->pagemap.data = devmem;
-
- mutex_lock(&hmm_devmem_lock);
- align_end = align_start + align_size - 1;
- for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) {
- struct hmm_devmem *dup;
-
- dup = radix_tree_lookup(&hmm_devmem_radix,
- key >> PA_SECTION_SHIFT);
- if (dup) {
- dev_err(device, "%s: collides with mapping for %s\n",
- __func__, dev_name(dup->device));
- mutex_unlock(&hmm_devmem_lock);
- ret = -EBUSY;
- goto error;
- }
- ret = radix_tree_insert(&hmm_devmem_radix,
- key >> PA_SECTION_SHIFT,
- devmem);
- if (ret) {
- dev_err(device, "%s: failed: %d\n", __func__, ret);
- mutex_unlock(&hmm_devmem_lock);
- goto error_radix;
- }
- }
- mutex_unlock(&hmm_devmem_lock);
-
- nid = dev_to_node(device);
- if (nid < 0)
- nid = numa_mem_id();
-
- mem_hotplug_begin();
- /*
- * For device private memory we call add_pages() as we only need to
- * allocate and initialize struct page for the device memory. More-
- * over the device memory is un-accessible thus we do not want to
- * create a linear mapping for the memory like arch_add_memory()
- * would do.
- *
- * For device public memory, which is accesible by the CPU, we do
- * want the linear mapping and thus use arch_add_memory().
- */
- if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC)
- ret = arch_add_memory(nid, align_start, align_size, NULL,
- false);
- else
- ret = add_pages(nid, align_start >> PAGE_SHIFT,
- align_size >> PAGE_SHIFT, NULL, false);
- if (ret) {
- mem_hotplug_done();
- goto error_add_memory;
- }
- move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
- align_start >> PAGE_SHIFT,
- align_size >> PAGE_SHIFT, NULL);
- mem_hotplug_done();
-
- for (pfn = devmem->pfn_first; pfn < devmem->pfn_last; pfn++) {
- struct page *page = pfn_to_page(pfn);
-
- page->pgmap = &devmem->pagemap;
- }
- return 0;
-
-error_add_memory:
- untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
-error_radix:
- hmm_devmem_radix_release(devmem->resource);
-error:
- return ret;
-}
-
-/*
- * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory
- *
- * @ops: memory event device driver callback (see struct hmm_devmem_ops)
- * @device: device struct to bind the resource too
- * @size: size in bytes of the device memory to add
- * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise
- *
- * This function first finds an empty range of physical address big enough to
- * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which
- * in turn allocates struct pages. It does not do anything beyond that; all
- * events affecting the memory will go through the various callbacks provided
- * by hmm_devmem_ops struct.
- *
- * Device driver should call this function during device initialization and
- * is then responsible of memory management. HMM only provides helpers.
- */
-struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
- struct device *device,
- unsigned long size)
-{
- struct hmm_devmem *devmem;
- resource_size_t addr;
- int ret;
-
- dev_pagemap_get_ops();
-
- devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
- if (!devmem)
- return ERR_PTR(-ENOMEM);
-
- init_completion(&devmem->completion);
- devmem->pfn_first = -1UL;
- devmem->pfn_last = -1UL;
- devmem->resource = NULL;
- devmem->device = device;
- devmem->ops = ops;
-
- ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
- 0, GFP_KERNEL);
- if (ret)
- return ERR_PTR(ret);
-
- ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref);
- if (ret)
- return ERR_PTR(ret);
-
- size = ALIGN(size, PA_SECTION_SIZE);
- addr = min((unsigned long)iomem_resource.end,
- (1UL << MAX_PHYSMEM_BITS) - 1);
- addr = addr - size + 1UL;
-
- /*
- * FIXME add a new helper to quickly walk resource tree and find free
- * range
- *
- * FIXME what about ioport_resource resource ?
- */
- for (; addr > size && addr >= iomem_resource.start; addr -= size) {
- ret = region_intersects(addr, size, 0, IORES_DESC_NONE);
- if (ret != REGION_DISJOINT)
- continue;
-
- devmem->resource = devm_request_mem_region(device, addr, size,
- dev_name(device));
- if (!devmem->resource)
- return ERR_PTR(-ENOMEM);
- break;
- }
- if (!devmem->resource)
- return ERR_PTR(-ERANGE);
-
- devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
- devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
- devmem->pfn_last = devmem->pfn_first +
- (resource_size(devmem->resource) >> PAGE_SHIFT);
-
- ret = hmm_devmem_pages_create(devmem);
- if (ret)
- return ERR_PTR(ret);
-
- ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
- if (ret)
- return ERR_PTR(ret);
-
- return devmem;
-}
-EXPORT_SYMBOL_GPL(hmm_devmem_add);
-
-struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
- struct device *device,
- struct resource *res)
-{
- struct hmm_devmem *devmem;
- int ret;
-
- if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
- return ERR_PTR(-EINVAL);
-
- dev_pagemap_get_ops();
-
- devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
- if (!devmem)
- return ERR_PTR(-ENOMEM);
-
- init_completion(&devmem->completion);
- devmem->pfn_first = -1UL;
- devmem->pfn_last = -1UL;
- devmem->resource = res;
- devmem->device = device;
- devmem->ops = ops;
-
- ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
- 0, GFP_KERNEL);
- if (ret)
- return ERR_PTR(ret);
-
- ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit,
- &devmem->ref);
- if (ret)
- return ERR_PTR(ret);
-
- devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
- devmem->pfn_last = devmem->pfn_first +
- (resource_size(devmem->resource) >> PAGE_SHIFT);
-
- ret = hmm_devmem_pages_create(devmem);
- if (ret)
- return ERR_PTR(ret);
-
- ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
- if (ret)
- return ERR_PTR(ret);
-
- ret = devm_add_action_or_reset(device, hmm_devmem_ref_kill,
- &devmem->ref);
- if (ret)
- return ERR_PTR(ret);
-
- return devmem;
-}
-EXPORT_SYMBOL_GPL(hmm_devmem_add_resource);
-
-/*
- * A device driver that wants to handle multiple devices memory through a
- * single fake device can use hmm_device to do so. This is purely a helper
- * and it is not needed to make use of any HMM functionality.
- */
-#define HMM_DEVICE_MAX 256
-
-static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX);
-static DEFINE_SPINLOCK(hmm_device_lock);
-static struct class *hmm_device_class;
-static dev_t hmm_device_devt;
-
-static void hmm_device_release(struct device *device)
-{
- struct hmm_device *hmm_device;
-
- hmm_device = container_of(device, struct hmm_device, device);
- spin_lock(&hmm_device_lock);
- clear_bit(hmm_device->minor, hmm_device_mask);
- spin_unlock(&hmm_device_lock);
-
- kfree(hmm_device);
-}
-
-struct hmm_device *hmm_device_new(void *drvdata)
-{
- struct hmm_device *hmm_device;
-
- hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL);
- if (!hmm_device)
- return ERR_PTR(-ENOMEM);
-
- spin_lock(&hmm_device_lock);
- hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX);
- if (hmm_device->minor >= HMM_DEVICE_MAX) {
- spin_unlock(&hmm_device_lock);
- kfree(hmm_device);
- return ERR_PTR(-EBUSY);
- }
- set_bit(hmm_device->minor, hmm_device_mask);
- spin_unlock(&hmm_device_lock);
-
- dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor);
- hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt),
- hmm_device->minor);
- hmm_device->device.release = hmm_device_release;
- dev_set_drvdata(&hmm_device->device, drvdata);
- hmm_device->device.class = hmm_device_class;
- device_initialize(&hmm_device->device);
-
- return hmm_device;
-}
-EXPORT_SYMBOL(hmm_device_new);
-
-void hmm_device_put(struct hmm_device *hmm_device)
-{
- put_device(&hmm_device->device);
-}
-EXPORT_SYMBOL(hmm_device_put);
-
-static int __init hmm_init(void)
-{
- int ret;
-
- ret = alloc_chrdev_region(&hmm_device_devt, 0,
- HMM_DEVICE_MAX,
- "hmm_device");
- if (ret)
- return ret;
-
- hmm_device_class = class_create(THIS_MODULE, "hmm_device");
- if (IS_ERR(hmm_device_class)) {
- unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX);
- return PTR_ERR(hmm_device_class);
- }
- return 0;
-}
-
-device_initcall(hmm_init);
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
+EXPORT_SYMBOL(hmm_range_fault);
--
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