diff options
Diffstat (limited to 'drivers/vfio/pci/vfio_pci_config.c')
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_config.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c index 7e2e62ab0869..97422aafaa7b 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -1966,3 +1966,45 @@ ssize_t vfio_pci_config_rw(struct vfio_pci_core_device *vdev, char __user *buf, return done; } + +/** + * vfio_pci_core_range_intersect_range() - Determine overlap between a buffer + * and register offset ranges. + * @buf_start: start offset of the buffer + * @buf_cnt: number of buffer bytes + * @reg_start: start register offset + * @reg_cnt: number of register bytes + * @buf_offset: start offset of overlap in the buffer + * @intersect_count: number of overlapping bytes + * @register_offset: start offset of overlap in register + * + * Returns: true if there is overlap, false if not. + * The overlap start and size is returned through function args. + */ +bool vfio_pci_core_range_intersect_range(loff_t buf_start, size_t buf_cnt, + loff_t reg_start, size_t reg_cnt, + loff_t *buf_offset, + size_t *intersect_count, + size_t *register_offset) +{ + if (buf_start <= reg_start && + buf_start + buf_cnt > reg_start) { + *buf_offset = reg_start - buf_start; + *intersect_count = min_t(size_t, reg_cnt, + buf_start + buf_cnt - reg_start); + *register_offset = 0; + return true; + } + + if (buf_start > reg_start && + buf_start < reg_start + reg_cnt) { + *buf_offset = 0; + *intersect_count = min_t(size_t, buf_cnt, + reg_start + reg_cnt - buf_start); + *register_offset = buf_start - reg_start; + return true; + } + + return false; +} +EXPORT_SYMBOL_GPL(vfio_pci_core_range_intersect_range); |