| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * Copyright 2013 Red Hat Inc. |
| * |
| * Authors: Jérôme Glisse <jglisse@redhat.com> |
| * |
| * See Documentation/vm/hmm.rst for reasons and overview of what HMM is. |
| */ |
| #ifndef LINUX_HMM_H |
| #define LINUX_HMM_H |
| |
| #include <linux/kconfig.h> |
| #include <linux/pgtable.h> |
| |
| #include <linux/device.h> |
| #include <linux/migrate.h> |
| #include <linux/memremap.h> |
| #include <linux/completion.h> |
| #include <linux/mmu_notifier.h> |
| |
| /* |
| * 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 |
| * |
| * 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_flags { |
| /* Output fields and 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), |
| HMM_PFN_ORDER_SHIFT = (BITS_PER_LONG - 8), |
| |
| /* Input flags */ |
| HMM_PFN_REQ_FAULT = HMM_PFN_VALID, |
| HMM_PFN_REQ_WRITE = HMM_PFN_WRITE, |
| |
| HMM_PFN_FLAGS = 0xFFUL << HMM_PFN_ORDER_SHIFT, |
| }; |
| |
| /* |
| * hmm_pfn_to_page() - return struct page pointed to by a device entry |
| * |
| * 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. |
| */ |
| static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn) |
| { |
| return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS); |
| } |
| |
| /* |
| * hmm_pfn_to_map_order() - return the CPU mapping size order |
| * |
| * This is optionally useful to optimize processing of the pfn result |
| * array. It indicates that the page starts at the order aligned VA and is |
| * 1<<order bytes long. Every pfn within an high order page will have the |
| * same pfn flags, both access protections and the map_order. The caller must |
| * be careful with edge cases as the start and end VA of the given page may |
| * extend past the range used with hmm_range_fault(). |
| * |
| * 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. |
| */ |
| static inline unsigned int hmm_pfn_to_map_order(unsigned long hmm_pfn) |
| { |
| return (hmm_pfn >> HMM_PFN_ORDER_SHIFT) & 0x1F; |
| } |
| |
| /* |
| * struct hmm_range - track invalidation lock on virtual address range |
| * |
| * @notifier: a mmu_interval_notifier that includes the start/end |
| * @notifier_seq: result of mmu_interval_read_begin() |
| * @start: range virtual start address (inclusive) |
| * @end: range virtual end address (exclusive) |
| * @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 |
| * @dev_private_owner: owner of device private pages |
| */ |
| struct hmm_range { |
| struct mmu_interval_notifier *notifier; |
| unsigned long notifier_seq; |
| unsigned long start; |
| unsigned long end; |
| unsigned long *hmm_pfns; |
| unsigned long default_flags; |
| unsigned long pfn_flags_mask; |
| void *dev_private_owner; |
| }; |
| |
| /* |
| * Please see Documentation/vm/hmm.rst for how to use the range API. |
| */ |
| int hmm_range_fault(struct hmm_range *range); |
| |
| /* |
| * HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range |
| * |
| * When waiting for mmu notifiers we need some kind of time out otherwise we |
| * could potentially wait for ever, 1000ms ie 1s sounds like a long time to |
| * wait already. |
| */ |
| #define HMM_RANGE_DEFAULT_TIMEOUT 1000 |
| |
| #endif /* LINUX_HMM_H */ |