qemu/util/userfaultfd.c

2  * Linux UFFD-WP support
10  * later.  See the COPYING file in the top-level directory.
15 #include "qemu/error-report.h"
37          * Make /dev/userfaultfd the default approach because it has better  in uffd_open()
38          * permission controls, meanwhile allows kernel faults without any  in uffd_open()
58     return -EINVAL;  in uffd_open()
63  * uffd_query_features: query UFFD features
67  * @features: parameter to receive 'uffdio_api.features'
69 int uffd_query_features(uint64_t *features)  in uffd_query_features()  argument
73     int ret = -1;  in uffd_query_features()
78         return -1;  in uffd_query_features()
82     api_struct.features = 0;  in uffd_query_features()
88     *features = api_struct.features;  in uffd_query_features()
99  * Returns non-negative file descriptor or negative value in case of an error
101  * @features: UFFD features to request
102  * @non_blocking: create UFFD file descriptor for non-blocking operation
104 int uffd_create_fd(uint64_t features, bool non_blocking)  in uffd_create_fd()  argument
115         return -1;  in uffd_create_fd()
119     api_struct.features = features;  in uffd_create_fd()
133     return -1;  in uffd_create_fd()
148  * uffd_register_memory: register memory range via UFFD-IO
169         return -1;  in uffd_register_memory()
179  * uffd_unregister_memory: un-register memory range with UFFD-IO
196         return -1;  in uffd_unregister_memory()
203  * uffd_change_protection: protect/un-protect memory range for writes via UFFD-IO
210  * @wp: write-protect/unprotect
211  * @dont_wake: do not wake threads waiting on wr-protected page
231         return -1;  in uffd_change_protection()
238  * uffd_copy_page: copy range of pages to destination via UFFD-IO
243  * Returns 0 on success, -errno in case of an error
266         return -e;  in uffd_copy_page()
273  * uffd_zero_page: fill range of pages with zeroes via UFFD-IO
277  * Returns 0 on success, -errno in case of an error
297         return -e;  in uffd_zero_page()
304  * uffd_wakeup: wake up threads waiting on page UFFD-managed page fault resolution
308  * via UFFD-IO IOCTLs with MODE_DONTWAKE flag set, then after that all waits
311  * Returns 0 on success, -errno in case of an error
328         return -e;  in uffd_wakeup()
356         return -1;  in uffd_read_events()