diff options
Diffstat (limited to 'include/linux/hmm.h')
| -rw-r--r-- | include/linux/hmm.h | 111 |
1 files changed, 39 insertions, 72 deletions
diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 7475051100c7..e912b9dc4633 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -19,51 +19,47 @@ #include <linux/mmu_notifier.h> /* - * hmm_pfn_flag_e - HMM flag enums + * On output: + * 0 - The page is faultable and a future call with + * HMM_PFN_REQ_FAULT could succeed. + * HMM_PFN_VALID - the pfn field points to a valid PFN. This PFN is at + * least readable. If dev_private_owner is !NULL then this could + * point at a DEVICE_PRIVATE page. + * HMM_PFN_WRITE - if the page memory can be written to (requires HMM_PFN_VALID) + * HMM_PFN_ERROR - accessing the pfn is impossible and the device should + * fail. ie poisoned memory, special pages, no vma, etc * - * Flags: - * HMM_PFN_VALID: pfn is valid. It has, at least, read permission. - * HMM_PFN_WRITE: CPU page table has write permission set - * - * The driver provides a flags array for mapping page protections to device - * PTE bits. If the driver valid bit for an entry is bit 3, - * i.e., (entry & (1 << 3)), then the driver must provide - * an array in hmm_range.flags with hmm_range.flags[HMM_PFN_VALID] == 1 << 3. - * Same logic apply to all flags. This is the same idea as vm_page_prot in vma - * except that this is per device driver rather than per architecture. + * On input: + * 0 - Return the current state of the page, do not fault it. + * HMM_PFN_REQ_FAULT - The output must have HMM_PFN_VALID or hmm_range_fault() + * will fail + * HMM_PFN_REQ_WRITE - The output must have HMM_PFN_WRITE or hmm_range_fault() + * will fail. Must be combined with HMM_PFN_REQ_FAULT. */ -enum hmm_pfn_flag_e { - HMM_PFN_VALID = 0, - HMM_PFN_WRITE, - HMM_PFN_FLAG_MAX +enum hmm_pfn_flags { + /* Output flags */ + HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1), + HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2), + HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3), + + /* Input flags */ + HMM_PFN_REQ_FAULT = HMM_PFN_VALID, + HMM_PFN_REQ_WRITE = HMM_PFN_WRITE, + + HMM_PFN_FLAGS = HMM_PFN_VALID | HMM_PFN_WRITE | HMM_PFN_ERROR, }; /* - * hmm_pfn_value_e - HMM pfn special value - * - * Flags: - * HMM_PFN_ERROR: corresponding CPU page table entry points to poisoned memory - * HMM_PFN_NONE: corresponding CPU page table entry is pte_none() - * HMM_PFN_SPECIAL: corresponding CPU page table entry is special; i.e., the - * result of vmf_insert_pfn() or vm_insert_page(). Therefore, it should not - * be mirrored by a device, because the entry will never have HMM_PFN_VALID - * set and the pfn value is undefined. + * hmm_pfn_to_page() - return struct page pointed to by a device entry * - * Driver provides values for none entry, error entry, and special entry. - * Driver can alias (i.e., use same value) error and special, but - * it should not alias none with error or special. - * - * HMM pfn value returned by hmm_vma_get_pfns() or hmm_vma_fault() will be: - * hmm_range.values[HMM_PFN_ERROR] if CPU page table entry is poisonous, - * hmm_range.values[HMM_PFN_NONE] if there is no CPU page table entry, - * hmm_range.values[HMM_PFN_SPECIAL] if CPU page table entry is a special one + * This must be called under the caller 'user_lock' after a successful + * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID + * already. */ -enum hmm_pfn_value_e { - HMM_PFN_ERROR, - HMM_PFN_NONE, - HMM_PFN_SPECIAL, - HMM_PFN_VALUE_MAX -}; +static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn) +{ + return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS); +} /* * struct hmm_range - track invalidation lock on virtual address range @@ -72,12 +68,9 @@ enum hmm_pfn_value_e { * @notifier_seq: result of mmu_interval_read_begin() * @start: range virtual start address (inclusive) * @end: range virtual end address (exclusive) - * @pfns: array of pfns (big enough for the range) - * @flags: pfn flags to match device driver page table - * @values: pfn value for some special case (none, special, error, ...) + * @hmm_pfns: array of pfns (big enough for the range) * @default_flags: default flags for the range (write, read, ... see hmm doc) * @pfn_flags_mask: allows to mask pfn flags so that only default_flags matter - * @pfn_shift: pfn shift value (should be <= PAGE_SHIFT) * @dev_private_owner: owner of device private pages */ struct hmm_range { @@ -85,42 +78,16 @@ struct hmm_range { unsigned long notifier_seq; unsigned long start; unsigned long end; - uint64_t *pfns; - const uint64_t *flags; - const uint64_t *values; - uint64_t default_flags; - uint64_t pfn_flags_mask; - uint8_t pfn_shift; + unsigned long *hmm_pfns; + unsigned long default_flags; + unsigned long pfn_flags_mask; void *dev_private_owner; }; /* - * hmm_device_entry_to_page() - return struct page pointed to by a device entry - * @range: range use to decode device entry value - * @entry: device entry value to get corresponding struct page from - * Return: struct page pointer if entry is a valid, NULL otherwise - * - * If the device entry is valid (ie valid flag set) then return the struct page - * matching the entry value. Otherwise return NULL. - */ -static inline struct page *hmm_device_entry_to_page(const struct hmm_range *range, - uint64_t entry) -{ - if (entry == range->values[HMM_PFN_NONE]) - return NULL; - if (entry == range->values[HMM_PFN_ERROR]) - return NULL; - if (entry == range->values[HMM_PFN_SPECIAL]) - return NULL; - if (!(entry & range->flags[HMM_PFN_VALID])) - return NULL; - return pfn_to_page(entry >> range->pfn_shift); -} - -/* * Please see Documentation/vm/hmm.rst for how to use the range API. */ -long hmm_range_fault(struct hmm_range *range); +int hmm_range_fault(struct hmm_range *range); /* * HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range |