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 void hmm_invalidate_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
}
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,
};
if (!mm || !mirror || !mirror->ops)
return -EINVAL;
+again:
mirror->hmm = hmm_register(mm);
if (!mirror->hmm)
return -ENOMEM;
down_write(&mirror->hmm->mirrors_sem);
- list_add(&mirror->list, &mirror->hmm->mirrors);
- up_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;
}
*/
void hmm_mirror_unregister(struct hmm_mirror *mirror)
{
- struct hmm *hmm = mirror->hmm;
+ 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(&mirror->list);
+ 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;
+
+ spin_lock(&mm->page_table_lock);
+ if (mm->hmm == hmm)
+ mm->hmm = NULL;
+ spin_unlock(&mm->page_table_lock);
+
+ mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm);
+ kfree(hmm);
}
EXPORT_SYMBOL(hmm_mirror_unregister);
unsigned long last;
bool fault;
bool block;
- bool write;
};
-static int hmm_vma_do_fault(struct mm_walk *walk,
- unsigned long addr,
- hmm_pfn_t *pfn)
+static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
+ bool write_fault, uint64_t *pfn)
{
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;
int r;
flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY;
- flags |= hmm_vma_walk->write ? FAULT_FLAG_WRITE : 0;
+ flags |= write_fault ? FAULT_FLAG_WRITE : 0;
r = handle_mm_fault(vma, addr, flags);
if (r & VM_FAULT_RETRY)
return -EBUSY;
if (r & VM_FAULT_ERROR) {
- *pfn = HMM_PFN_ERROR;
+ *pfn = range->values[HMM_PFN_ERROR];
return -EFAULT;
}
return -EAGAIN;
}
-static void hmm_pfns_special(hmm_pfn_t *pfns,
- unsigned long addr,
- unsigned long end)
-{
- for (; addr < end; addr += PAGE_SIZE, pfns++)
- *pfns = HMM_PFN_SPECIAL;
-}
-
static int hmm_pfns_bad(unsigned long addr,
unsigned long end,
struct mm_walk *walk)
{
- struct hmm_range *range = walk->private;
- hmm_pfn_t *pfns = range->pfns;
+ 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] = HMM_PFN_ERROR;
+ pfns[i] = range->values[HMM_PFN_ERROR];
return 0;
}
-static void hmm_pfns_clear(hmm_pfn_t *pfns,
- unsigned long addr,
- unsigned long end)
-{
- for (; addr < end; addr += PAGE_SIZE, pfns++)
- *pfns = 0;
-}
-
-static int hmm_vma_walk_hole(unsigned long addr,
- unsigned long end,
- struct mm_walk *walk)
+/*
+ * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s)
+ * @start: range virtual start address (inclusive)
+ * @end: range virtual end address (exclusive)
+ * @fault: should we fault or not ?
+ * @write_fault: write fault ?
+ * @walk: mm_walk structure
+ * Returns: 0 on success, -EAGAIN 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)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- hmm_pfn_t *pfns = range->pfns;
+ uint64_t *pfns = range->pfns;
unsigned long i;
hmm_vma_walk->last = addr;
i = (addr - range->start) >> PAGE_SHIFT;
for (; addr < end; addr += PAGE_SIZE, i++) {
- pfns[i] = HMM_PFN_EMPTY;
- if (hmm_vma_walk->fault) {
+ pfns[i] = range->values[HMM_PFN_NONE];
+ if (fault || write_fault) {
int ret;
- ret = hmm_vma_do_fault(walk, addr, &pfns[i]);
+ ret = hmm_vma_do_fault(walk, addr, write_fault,
+ &pfns[i]);
if (ret != -EAGAIN)
return ret;
}
}
- return hmm_vma_walk->fault ? -EAGAIN : 0;
+ return (fault || write_fault) ? -EAGAIN : 0;
}
-static int hmm_vma_walk_clear(unsigned long addr,
- unsigned long end,
- struct mm_walk *walk)
+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)
{
- struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- hmm_pfn_t *pfns = range->pfns;
+
+ *fault = *write_fault = false;
+ if (!hmm_vma_walk->fault)
+ return;
+
+ /* 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 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;
+ }
+}
+
+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)
+{
unsigned long i;
- hmm_vma_walk->last = addr;
+ if (!hmm_vma_walk->fault) {
+ *fault = *write_fault = false;
+ return;
+ }
+
+ 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;
+ }
+}
+
+static int hmm_vma_walk_hole(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;
+ bool fault, write_fault;
+ unsigned long i, npages;
+ uint64_t *pfns;
+
i = (addr - range->start) >> PAGE_SHIFT;
- for (; addr < end; addr += PAGE_SIZE, i++) {
- pfns[i] = 0;
- if (hmm_vma_walk->fault) {
- int ret;
+ 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);
+}
- ret = hmm_vma_do_fault(walk, addr, &pfns[i]);
- if (ret != -EAGAIN)
- return ret;
+static inline uint64_t 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];
+}
+
+static int hmm_vma_handle_pmd(struct mm_walk *walk,
+ unsigned long addr,
+ unsigned long end,
+ uint64_t *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;
+
+ 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);
+
+ 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);
+ 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;
+ return 0;
+}
+
+static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte)
+{
+ if (pte_none(pte) || !pte_present(pte))
+ return 0;
+ return pte_write(pte) ? range->flags[HMM_PFN_VALID] |
+ range->flags[HMM_PFN_WRITE] :
+ range->flags[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)
+{
+ 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;
+ 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);
+
+ if (pte_none(pte)) {
+ if (fault || write_fault)
+ goto fault;
+ 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;
+ 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;
+ return 0;
+ }
+
+ 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;
+ }
+
+ /* Report error for everything else */
+ *pfn = range->values[HMM_PFN_ERROR];
+ return -EFAULT;
}
- return hmm_vma_walk->fault ? -EAGAIN : 0;
+ if (fault || write_fault)
+ goto fault;
+
+ *pfn = hmm_pfn_from_pfn(range, 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);
}
static int hmm_vma_walk_pmd(pmd_t *pmdp,
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- struct vm_area_struct *vma = walk->vma;
- hmm_pfn_t *pfns = range->pfns;
+ uint64_t *pfns = range->pfns;
unsigned long addr = start, i;
- bool write_fault;
- hmm_pfn_t flag;
pte_t *ptep;
i = (addr - range->start) >> PAGE_SHIFT;
- flag = vma->vm_flags & VM_READ ? HMM_PFN_READ : 0;
- write_fault = hmm_vma_walk->fault & hmm_vma_walk->write;
again:
if (pmd_none(*pmdp))
return hmm_vma_walk_hole(start, end, walk);
- if (pmd_huge(*pmdp) && vma->vm_flags & VM_HUGETLB)
+ if (pmd_huge(*pmdp) && (range->vma->vm_flags & VM_HUGETLB))
return hmm_pfns_bad(start, end, walk);
if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) {
- unsigned long pfn;
pmd_t pmd;
/*
barrier();
if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
goto again;
- if (pmd_protnone(pmd))
- return hmm_vma_walk_clear(start, end, walk);
- if (write_fault && !pmd_write(pmd))
- return hmm_vma_walk_clear(start, end, walk);
-
- pfn = pmd_pfn(pmd) + pte_index(addr);
- flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
- for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
- pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
- return 0;
+ return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd);
}
if (pmd_bad(*pmdp))
ptep = pte_offset_map(pmdp, addr);
for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
- pte_t pte = *ptep;
-
- pfns[i] = 0;
+ int r;
- if (pte_none(pte)) {
- pfns[i] = HMM_PFN_EMPTY;
- if (hmm_vma_walk->fault)
- goto fault;
- continue;
+ r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]);
+ if (r) {
+ /* hmm_vma_handle_pte() did unmap pte directory */
+ hmm_vma_walk->last = addr;
+ return r;
}
-
- if (!pte_present(pte)) {
- swp_entry_t entry = pte_to_swp_entry(pte);
-
- if (!non_swap_entry(entry)) {
- if (hmm_vma_walk->fault)
- goto fault;
- continue;
- }
-
- /*
- * This is a special swap entry, ignore migration, use
- * device and report anything else as error.
- */
- if (is_device_private_entry(entry)) {
- pfns[i] = hmm_pfn_t_from_pfn(swp_offset(entry));
- if (is_write_device_private_entry(entry)) {
- pfns[i] |= HMM_PFN_WRITE;
- } else if (write_fault)
- goto fault;
- pfns[i] |= HMM_PFN_DEVICE_UNADDRESSABLE;
- pfns[i] |= flag;
- } else if (is_migration_entry(entry)) {
- if (hmm_vma_walk->fault) {
- pte_unmap(ptep);
- hmm_vma_walk->last = addr;
- migration_entry_wait(vma->vm_mm,
- pmdp, addr);
- return -EAGAIN;
- }
- continue;
- } else {
- /* Report error for everything else */
- pfns[i] = HMM_PFN_ERROR;
- }
- continue;
- }
-
- if (write_fault && !pte_write(pte))
- goto fault;
-
- pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag;
- pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
- continue;
-
-fault:
- pte_unmap(ptep);
- /* Fault all pages in range */
- return hmm_vma_walk_clear(start, end, walk);
}
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)
+{
+ for (; addr < end; addr += PAGE_SIZE, pfns++)
+ *pfns = range->values[HMM_PFN_NONE];
+}
+
+static void hmm_pfns_special(struct hmm_range *range)
+{
+ unsigned long addr = range->start, i = 0;
+
+ for (; addr < range->end; addr += PAGE_SIZE, i++)
+ range->pfns[i] = range->values[HMM_PFN_SPECIAL];
+}
+
/*
* hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
- * @vma: virtual memory area containing the virtual address range
- * @range: used to track snapshot validity
- * @start: range virtual start address (inclusive)
- * @end: range virtual end address (exclusive)
- * @entries: array of hmm_pfn_t: provided by the caller, filled in by function
- * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, 0 success
+ * @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
* 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 vm_area_struct *vma,
- struct hmm_range *range,
- unsigned long start,
- unsigned long end,
- hmm_pfn_t *pfns)
+int hmm_vma_get_pfns(struct hmm_range *range)
{
+ struct vm_area_struct *vma = range->vma;
struct hmm_vma_walk hmm_vma_walk;
struct mm_walk mm_walk;
struct hmm *hmm;
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
- hmm_pfns_special(pfns, start, end);
- return -EINVAL;
- }
-
/* Sanity check, this really should not happen ! */
- if (start < vma->vm_start || start >= vma->vm_end)
+ if (range->start < vma->vm_start || range->start >= vma->vm_end)
return -EINVAL;
- if (end < vma->vm_start || end > vma->vm_end)
+ if (range->end < vma->vm_start || range->end > vma->vm_end)
return -EINVAL;
hmm = hmm_register(vma->vm_mm);
if (!hmm->mmu_notifier.ops)
return -EINVAL;
+ /* FIXME support hugetlb fs */
+ if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
+ 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 */
- range->start = start;
- range->pfns = pfns;
- range->end = end;
spin_lock(&hmm->lock);
range->valid = true;
list_add_rcu(&range->list, &hmm->ranges);
mm_walk.pmd_entry = hmm_vma_walk_pmd;
mm_walk.pte_hole = hmm_vma_walk_hole;
- walk_page_range(start, end, &mm_walk);
+ walk_page_range(range->start, range->end, &mm_walk);
return 0;
}
EXPORT_SYMBOL(hmm_vma_get_pfns);
/*
* hmm_vma_range_done() - stop tracking change to CPU page table over a range
- * @vma: virtual memory area containing the virtual address range
* @range: range being tracked
* Returns: false if range data has been invalidated, true otherwise
*
*
* There are two ways to use this :
* again:
- * hmm_vma_get_pfns(vma, range, start, end, pfns); or hmm_vma_fault(...);
+ * 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(vma, range)) {
+ * if (!hmm_vma_range_done(range)) {
* device_page_table_unlock();
* goto again;
* }
* device_page_table_unlock();
*
* Or:
- * hmm_vma_get_pfns(vma, range, start, end, pfns); or hmm_vma_fault(...);
+ * hmm_vma_get_pfns(range); or hmm_vma_fault(...);
* device_page_table_lock();
- * hmm_vma_range_done(vma, range);
- * device_update_page_table(pfns);
+ * hmm_vma_range_done(range);
+ * device_update_page_table(range->pfns);
* device_page_table_unlock();
*/
-bool hmm_vma_range_done(struct vm_area_struct *vma, struct hmm_range *range)
+bool hmm_vma_range_done(struct hmm_range *range)
{
unsigned long npages = (range->end - range->start) >> PAGE_SHIFT;
struct hmm *hmm;
return false;
}
- hmm = hmm_register(vma->vm_mm);
+ hmm = hmm_register(range->vma->vm_mm);
if (!hmm) {
memset(range->pfns, 0, sizeof(*range->pfns) * npages);
return false;
/*
* hmm_vma_fault() - try to fault some address in a virtual address range
- * @vma: virtual memory area containing the virtual address range
- * @range: use to track pfns array content validity
- * @start: fault range virtual start address (inclusive)
- * @end: fault range virtual end address (exclusive)
- * @pfns: array of hmm_pfn_t, only entry with fault flag set will be faulted
- * @write: is it a write fault
+ * @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)
*
* 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.
*
- * On error, for one virtual address in the range, the function will set the
- * hmm_pfn_t error flag for the corresponding pfn entry.
+ * On error, for one virtual address in the range, the function will mark the
+ * corresponding HMM pfn entry with an error flag.
*
* 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(vma, start, end, pfns, allow_retry);
+ * ret = hmm_vma_fault(range, write, block);
* switch (ret) {
* case -EAGAIN:
- * hmm_vma_range_done(vma, range);
+ * 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)
* }
* // Take device driver lock that serialize device page table update
* driver_lock_device_page_table_update();
- * hmm_vma_range_done(vma, range);
+ * 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 HAVE BEEN WARNED !
*/
-int hmm_vma_fault(struct vm_area_struct *vma,
- struct hmm_range *range,
- unsigned long start,
- unsigned long end,
- hmm_pfn_t *pfns,
- bool write,
- bool block)
+int hmm_vma_fault(struct hmm_range *range, bool block)
{
+ 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;
int ret;
/* Sanity check, this really should not happen ! */
- if (start < vma->vm_start || start >= vma->vm_end)
+ if (range->start < vma->vm_start || range->start >= vma->vm_end)
return -EINVAL;
- if (end < vma->vm_start || end > vma->vm_end)
+ if (range->end < vma->vm_start || range->end > vma->vm_end)
return -EINVAL;
hmm = hmm_register(vma->vm_mm);
if (!hmm) {
- hmm_pfns_clear(pfns, start, end);
+ 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)) {
+ 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 */
- range->start = start;
- range->pfns = pfns;
- range->end = end;
spin_lock(&hmm->lock);
range->valid = true;
list_add_rcu(&range->list, &hmm->ranges);
spin_unlock(&hmm->lock);
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
- hmm_pfns_special(pfns, start, end);
- return 0;
- }
-
hmm_vma_walk.fault = true;
- hmm_vma_walk.write = write;
hmm_vma_walk.block = block;
hmm_vma_walk.range = range;
mm_walk.private = &hmm_vma_walk;
mm_walk.pte_hole = hmm_vma_walk_hole;
do {
- ret = walk_page_range(start, end, &mm_walk);
+ ret = walk_page_range(start, range->end, &mm_walk);
start = hmm_vma_walk.last;
} while (ret == -EAGAIN);
unsigned long i;
i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
- hmm_pfns_clear(&pfns[i], hmm_vma_walk.last, end);
- hmm_vma_range_done(vma, range);
+ hmm_pfns_clear(range, &range->pfns[i], hmm_vma_walk.last,
+ range->end);
+ hmm_vma_range_done(range);
}
return ret;
}
hmm_devmem_radix_release(resource);
}
-static struct hmm_devmem *hmm_devmem_find(resource_size_t phys)
-{
- WARN_ON_ONCE(!rcu_read_lock_held());
-
- return radix_tree_lookup(&hmm_devmem_radix, phys >> PA_SECTION_SHIFT);
-}
-
static int hmm_devmem_pages_create(struct hmm_devmem *devmem)
{
resource_size_t key, align_start, align_size, align_end;
for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) {
struct hmm_devmem *dup;
- rcu_read_lock();
- dup = hmm_devmem_find(key);
- rcu_read_unlock();
+ 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));
git.samba.org / sfrench / cifs-2.6.git / blobdiff