1*dd873966SEric Auger /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2c1fcf220SDr. David Alan Gilbert /* 3c1fcf220SDr. David Alan Gilbert * include/linux/userfaultfd.h 4c1fcf220SDr. David Alan Gilbert * 5c1fcf220SDr. David Alan Gilbert * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> 6c1fcf220SDr. David Alan Gilbert * Copyright (C) 2015 Red Hat, Inc. 7c1fcf220SDr. David Alan Gilbert * 8c1fcf220SDr. David Alan Gilbert */ 9c1fcf220SDr. David Alan Gilbert 10c1fcf220SDr. David Alan Gilbert #ifndef _LINUX_USERFAULTFD_H 11c1fcf220SDr. David Alan Gilbert #define _LINUX_USERFAULTFD_H 12c1fcf220SDr. David Alan Gilbert 13c1fcf220SDr. David Alan Gilbert #include <linux/types.h> 14c1fcf220SDr. David Alan Gilbert 15c1fcf220SDr. David Alan Gilbert /* 163a5eb5b4SPaolo Bonzini * If the UFFDIO_API is upgraded someday, the UFFDIO_UNREGISTER and 173a5eb5b4SPaolo Bonzini * UFFDIO_WAKE ioctls should be defined as _IOW and not as _IOR. In 183a5eb5b4SPaolo Bonzini * userfaultfd.h we assumed the kernel was reading (instead _IOC_READ 193a5eb5b4SPaolo Bonzini * means the userland is reading). 20c1fcf220SDr. David Alan Gilbert */ 213a5eb5b4SPaolo Bonzini #define UFFD_API ((__u64)0xAA) 223a5eb5b4SPaolo Bonzini #define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_FORK | \ 233a5eb5b4SPaolo Bonzini UFFD_FEATURE_EVENT_REMAP | \ 2474c98e20SCornelia Huck UFFD_FEATURE_EVENT_REMOVE | \ 2574c98e20SCornelia Huck UFFD_FEATURE_EVENT_UNMAP | \ 263a5eb5b4SPaolo Bonzini UFFD_FEATURE_MISSING_HUGETLBFS | \ 27d4083f50SAlexey Perevalov UFFD_FEATURE_MISSING_SHMEM | \ 28d4083f50SAlexey Perevalov UFFD_FEATURE_SIGBUS | \ 29d4083f50SAlexey Perevalov UFFD_FEATURE_THREAD_ID) 30c1fcf220SDr. David Alan Gilbert #define UFFD_API_IOCTLS \ 31c1fcf220SDr. David Alan Gilbert ((__u64)1 << _UFFDIO_REGISTER | \ 32c1fcf220SDr. David Alan Gilbert (__u64)1 << _UFFDIO_UNREGISTER | \ 33c1fcf220SDr. David Alan Gilbert (__u64)1 << _UFFDIO_API) 34c1fcf220SDr. David Alan Gilbert #define UFFD_API_RANGE_IOCTLS \ 35c1fcf220SDr. David Alan Gilbert ((__u64)1 << _UFFDIO_WAKE | \ 36c1fcf220SDr. David Alan Gilbert (__u64)1 << _UFFDIO_COPY | \ 37c1fcf220SDr. David Alan Gilbert (__u64)1 << _UFFDIO_ZEROPAGE) 383a5eb5b4SPaolo Bonzini #define UFFD_API_RANGE_IOCTLS_BASIC \ 393a5eb5b4SPaolo Bonzini ((__u64)1 << _UFFDIO_WAKE | \ 403a5eb5b4SPaolo Bonzini (__u64)1 << _UFFDIO_COPY) 41c1fcf220SDr. David Alan Gilbert 42c1fcf220SDr. David Alan Gilbert /* 43c1fcf220SDr. David Alan Gilbert * Valid ioctl command number range with this API is from 0x00 to 44c1fcf220SDr. David Alan Gilbert * 0x3F. UFFDIO_API is the fixed number, everything else can be 45c1fcf220SDr. David Alan Gilbert * changed by implementing a different UFFD_API. If sticking to the 46c1fcf220SDr. David Alan Gilbert * same UFFD_API more ioctl can be added and userland will be aware of 47c1fcf220SDr. David Alan Gilbert * which ioctl the running kernel implements through the ioctl command 48c1fcf220SDr. David Alan Gilbert * bitmask written by the UFFDIO_API. 49c1fcf220SDr. David Alan Gilbert */ 50c1fcf220SDr. David Alan Gilbert #define _UFFDIO_REGISTER (0x00) 51c1fcf220SDr. David Alan Gilbert #define _UFFDIO_UNREGISTER (0x01) 52c1fcf220SDr. David Alan Gilbert #define _UFFDIO_WAKE (0x02) 53c1fcf220SDr. David Alan Gilbert #define _UFFDIO_COPY (0x03) 54c1fcf220SDr. David Alan Gilbert #define _UFFDIO_ZEROPAGE (0x04) 55c1fcf220SDr. David Alan Gilbert #define _UFFDIO_API (0x3F) 56c1fcf220SDr. David Alan Gilbert 57c1fcf220SDr. David Alan Gilbert /* userfaultfd ioctl ids */ 58c1fcf220SDr. David Alan Gilbert #define UFFDIO 0xAA 59c1fcf220SDr. David Alan Gilbert #define UFFDIO_API _IOWR(UFFDIO, _UFFDIO_API, \ 60c1fcf220SDr. David Alan Gilbert struct uffdio_api) 61c1fcf220SDr. David Alan Gilbert #define UFFDIO_REGISTER _IOWR(UFFDIO, _UFFDIO_REGISTER, \ 62c1fcf220SDr. David Alan Gilbert struct uffdio_register) 63c1fcf220SDr. David Alan Gilbert #define UFFDIO_UNREGISTER _IOR(UFFDIO, _UFFDIO_UNREGISTER, \ 64c1fcf220SDr. David Alan Gilbert struct uffdio_range) 65c1fcf220SDr. David Alan Gilbert #define UFFDIO_WAKE _IOR(UFFDIO, _UFFDIO_WAKE, \ 66c1fcf220SDr. David Alan Gilbert struct uffdio_range) 67c1fcf220SDr. David Alan Gilbert #define UFFDIO_COPY _IOWR(UFFDIO, _UFFDIO_COPY, \ 68c1fcf220SDr. David Alan Gilbert struct uffdio_copy) 69c1fcf220SDr. David Alan Gilbert #define UFFDIO_ZEROPAGE _IOWR(UFFDIO, _UFFDIO_ZEROPAGE, \ 70c1fcf220SDr. David Alan Gilbert struct uffdio_zeropage) 71c1fcf220SDr. David Alan Gilbert 72c1fcf220SDr. David Alan Gilbert /* read() structure */ 73c1fcf220SDr. David Alan Gilbert struct uffd_msg { 74c1fcf220SDr. David Alan Gilbert __u8 event; 75c1fcf220SDr. David Alan Gilbert 76c1fcf220SDr. David Alan Gilbert __u8 reserved1; 77c1fcf220SDr. David Alan Gilbert __u16 reserved2; 78c1fcf220SDr. David Alan Gilbert __u32 reserved3; 79c1fcf220SDr. David Alan Gilbert 80c1fcf220SDr. David Alan Gilbert union { 81c1fcf220SDr. David Alan Gilbert struct { 82c1fcf220SDr. David Alan Gilbert __u64 flags; 83c1fcf220SDr. David Alan Gilbert __u64 address; 84d4083f50SAlexey Perevalov union { 85d4083f50SAlexey Perevalov __u32 ptid; 86d4083f50SAlexey Perevalov } feat; 87c1fcf220SDr. David Alan Gilbert } pagefault; 88c1fcf220SDr. David Alan Gilbert 89c1fcf220SDr. David Alan Gilbert struct { 903a5eb5b4SPaolo Bonzini __u32 ufd; 913a5eb5b4SPaolo Bonzini } fork; 923a5eb5b4SPaolo Bonzini 933a5eb5b4SPaolo Bonzini struct { 943a5eb5b4SPaolo Bonzini __u64 from; 953a5eb5b4SPaolo Bonzini __u64 to; 963a5eb5b4SPaolo Bonzini __u64 len; 973a5eb5b4SPaolo Bonzini } remap; 983a5eb5b4SPaolo Bonzini 993a5eb5b4SPaolo Bonzini struct { 1003a5eb5b4SPaolo Bonzini __u64 start; 1013a5eb5b4SPaolo Bonzini __u64 end; 10274c98e20SCornelia Huck } remove; 1033a5eb5b4SPaolo Bonzini 1043a5eb5b4SPaolo Bonzini struct { 105c1fcf220SDr. David Alan Gilbert /* unused reserved fields */ 106c1fcf220SDr. David Alan Gilbert __u64 reserved1; 107c1fcf220SDr. David Alan Gilbert __u64 reserved2; 108c1fcf220SDr. David Alan Gilbert __u64 reserved3; 109c1fcf220SDr. David Alan Gilbert } reserved; 110c1fcf220SDr. David Alan Gilbert } arg; 111b89485a5SPaolo Bonzini } __attribute__((packed)); 112c1fcf220SDr. David Alan Gilbert 113c1fcf220SDr. David Alan Gilbert /* 114c1fcf220SDr. David Alan Gilbert * Start at 0x12 and not at 0 to be more strict against bugs. 115c1fcf220SDr. David Alan Gilbert */ 116c1fcf220SDr. David Alan Gilbert #define UFFD_EVENT_PAGEFAULT 0x12 117c1fcf220SDr. David Alan Gilbert #define UFFD_EVENT_FORK 0x13 1183a5eb5b4SPaolo Bonzini #define UFFD_EVENT_REMAP 0x14 11974c98e20SCornelia Huck #define UFFD_EVENT_REMOVE 0x15 12074c98e20SCornelia Huck #define UFFD_EVENT_UNMAP 0x16 121c1fcf220SDr. David Alan Gilbert 122c1fcf220SDr. David Alan Gilbert /* flags for UFFD_EVENT_PAGEFAULT */ 123c1fcf220SDr. David Alan Gilbert #define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */ 124c1fcf220SDr. David Alan Gilbert #define UFFD_PAGEFAULT_FLAG_WP (1<<1) /* If reason is VM_UFFD_WP */ 125c1fcf220SDr. David Alan Gilbert 126c1fcf220SDr. David Alan Gilbert struct uffdio_api { 127c1fcf220SDr. David Alan Gilbert /* userland asks for an API number and the features to enable */ 128c1fcf220SDr. David Alan Gilbert __u64 api; 129c1fcf220SDr. David Alan Gilbert /* 130c1fcf220SDr. David Alan Gilbert * Kernel answers below with the all available features for 131c1fcf220SDr. David Alan Gilbert * the API, this notifies userland of which events and/or 132c1fcf220SDr. David Alan Gilbert * which flags for each event are enabled in the current 133c1fcf220SDr. David Alan Gilbert * kernel. 134c1fcf220SDr. David Alan Gilbert * 135c1fcf220SDr. David Alan Gilbert * Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE 136c1fcf220SDr. David Alan Gilbert * are to be considered implicitly always enabled in all kernels as 137c1fcf220SDr. David Alan Gilbert * long as the uffdio_api.api requested matches UFFD_API. 1383a5eb5b4SPaolo Bonzini * 1393a5eb5b4SPaolo Bonzini * UFFD_FEATURE_MISSING_HUGETLBFS means an UFFDIO_REGISTER 1403a5eb5b4SPaolo Bonzini * with UFFDIO_REGISTER_MODE_MISSING mode will succeed on 1413a5eb5b4SPaolo Bonzini * hugetlbfs virtual memory ranges. Adding or not adding 1423a5eb5b4SPaolo Bonzini * UFFD_FEATURE_MISSING_HUGETLBFS to uffdio_api.features has 1433a5eb5b4SPaolo Bonzini * no real functional effect after UFFDIO_API returns, but 1443a5eb5b4SPaolo Bonzini * it's only useful for an initial feature set probe at 1453a5eb5b4SPaolo Bonzini * UFFDIO_API time. There are two ways to use it: 1463a5eb5b4SPaolo Bonzini * 1473a5eb5b4SPaolo Bonzini * 1) by adding UFFD_FEATURE_MISSING_HUGETLBFS to the 1483a5eb5b4SPaolo Bonzini * uffdio_api.features before calling UFFDIO_API, an error 1493a5eb5b4SPaolo Bonzini * will be returned by UFFDIO_API on a kernel without 1503a5eb5b4SPaolo Bonzini * hugetlbfs missing support 1513a5eb5b4SPaolo Bonzini * 1523a5eb5b4SPaolo Bonzini * 2) the UFFD_FEATURE_MISSING_HUGETLBFS can not be added in 1533a5eb5b4SPaolo Bonzini * uffdio_api.features and instead it will be set by the 1543a5eb5b4SPaolo Bonzini * kernel in the uffdio_api.features if the kernel supports 1553a5eb5b4SPaolo Bonzini * it, so userland can later check if the feature flag is 1563a5eb5b4SPaolo Bonzini * present in uffdio_api.features after UFFDIO_API 1573a5eb5b4SPaolo Bonzini * succeeded. 1583a5eb5b4SPaolo Bonzini * 1593a5eb5b4SPaolo Bonzini * UFFD_FEATURE_MISSING_SHMEM works the same as 1603a5eb5b4SPaolo Bonzini * UFFD_FEATURE_MISSING_HUGETLBFS, but it applies to shmem 1613a5eb5b4SPaolo Bonzini * (i.e. tmpfs and other shmem based APIs). 162d4083f50SAlexey Perevalov * 163d4083f50SAlexey Perevalov * UFFD_FEATURE_SIGBUS feature means no page-fault 164d4083f50SAlexey Perevalov * (UFFD_EVENT_PAGEFAULT) event will be delivered, instead 165d4083f50SAlexey Perevalov * a SIGBUS signal will be sent to the faulting process. 166d4083f50SAlexey Perevalov * 167d4083f50SAlexey Perevalov * UFFD_FEATURE_THREAD_ID pid of the page faulted task_struct will 168d4083f50SAlexey Perevalov * be returned, if feature is not requested 0 will be returned. 169c1fcf220SDr. David Alan Gilbert */ 170c1fcf220SDr. David Alan Gilbert #define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) 171c1fcf220SDr. David Alan Gilbert #define UFFD_FEATURE_EVENT_FORK (1<<1) 1723a5eb5b4SPaolo Bonzini #define UFFD_FEATURE_EVENT_REMAP (1<<2) 17374c98e20SCornelia Huck #define UFFD_FEATURE_EVENT_REMOVE (1<<3) 1743a5eb5b4SPaolo Bonzini #define UFFD_FEATURE_MISSING_HUGETLBFS (1<<4) 1753a5eb5b4SPaolo Bonzini #define UFFD_FEATURE_MISSING_SHMEM (1<<5) 17674c98e20SCornelia Huck #define UFFD_FEATURE_EVENT_UNMAP (1<<6) 177d4083f50SAlexey Perevalov #define UFFD_FEATURE_SIGBUS (1<<7) 178d4083f50SAlexey Perevalov #define UFFD_FEATURE_THREAD_ID (1<<8) 179c1fcf220SDr. David Alan Gilbert __u64 features; 180c1fcf220SDr. David Alan Gilbert 181c1fcf220SDr. David Alan Gilbert __u64 ioctls; 182c1fcf220SDr. David Alan Gilbert }; 183c1fcf220SDr. David Alan Gilbert 184c1fcf220SDr. David Alan Gilbert struct uffdio_range { 185c1fcf220SDr. David Alan Gilbert __u64 start; 186c1fcf220SDr. David Alan Gilbert __u64 len; 187c1fcf220SDr. David Alan Gilbert }; 188c1fcf220SDr. David Alan Gilbert 189c1fcf220SDr. David Alan Gilbert struct uffdio_register { 190c1fcf220SDr. David Alan Gilbert struct uffdio_range range; 191c1fcf220SDr. David Alan Gilbert #define UFFDIO_REGISTER_MODE_MISSING ((__u64)1<<0) 192c1fcf220SDr. David Alan Gilbert #define UFFDIO_REGISTER_MODE_WP ((__u64)1<<1) 193c1fcf220SDr. David Alan Gilbert __u64 mode; 194c1fcf220SDr. David Alan Gilbert 195c1fcf220SDr. David Alan Gilbert /* 196c1fcf220SDr. David Alan Gilbert * kernel answers which ioctl commands are available for the 197c1fcf220SDr. David Alan Gilbert * range, keep at the end as the last 8 bytes aren't read. 198c1fcf220SDr. David Alan Gilbert */ 199c1fcf220SDr. David Alan Gilbert __u64 ioctls; 200c1fcf220SDr. David Alan Gilbert }; 201c1fcf220SDr. David Alan Gilbert 202c1fcf220SDr. David Alan Gilbert struct uffdio_copy { 203c1fcf220SDr. David Alan Gilbert __u64 dst; 204c1fcf220SDr. David Alan Gilbert __u64 src; 205c1fcf220SDr. David Alan Gilbert __u64 len; 206c1fcf220SDr. David Alan Gilbert /* 207c1fcf220SDr. David Alan Gilbert * There will be a wrprotection flag later that allows to map 208c1fcf220SDr. David Alan Gilbert * pages wrprotected on the fly. And such a flag will be 209c1fcf220SDr. David Alan Gilbert * available if the wrprotection ioctl are implemented for the 210c1fcf220SDr. David Alan Gilbert * range according to the uffdio_register.ioctls. 211c1fcf220SDr. David Alan Gilbert */ 212c1fcf220SDr. David Alan Gilbert #define UFFDIO_COPY_MODE_DONTWAKE ((__u64)1<<0) 213c1fcf220SDr. David Alan Gilbert __u64 mode; 214c1fcf220SDr. David Alan Gilbert 215c1fcf220SDr. David Alan Gilbert /* 216c1fcf220SDr. David Alan Gilbert * "copy" is written by the ioctl and must be at the end: the 217c1fcf220SDr. David Alan Gilbert * copy_from_user will not read the last 8 bytes. 218c1fcf220SDr. David Alan Gilbert */ 219c1fcf220SDr. David Alan Gilbert __s64 copy; 220c1fcf220SDr. David Alan Gilbert }; 221c1fcf220SDr. David Alan Gilbert 222c1fcf220SDr. David Alan Gilbert struct uffdio_zeropage { 223c1fcf220SDr. David Alan Gilbert struct uffdio_range range; 224c1fcf220SDr. David Alan Gilbert #define UFFDIO_ZEROPAGE_MODE_DONTWAKE ((__u64)1<<0) 225c1fcf220SDr. David Alan Gilbert __u64 mode; 226c1fcf220SDr. David Alan Gilbert 227c1fcf220SDr. David Alan Gilbert /* 228c1fcf220SDr. David Alan Gilbert * "zeropage" is written by the ioctl and must be at the end: 229c1fcf220SDr. David Alan Gilbert * the copy_from_user will not read the last 8 bytes. 230c1fcf220SDr. David Alan Gilbert */ 231c1fcf220SDr. David Alan Gilbert __s64 zeropage; 232c1fcf220SDr. David Alan Gilbert }; 233c1fcf220SDr. David Alan Gilbert 234c1fcf220SDr. David Alan Gilbert #endif /* _LINUX_USERFAULTFD_H */ 235