Header file copied from vfio live migration patch series v8. [1]. [1] https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg05542.html Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx> Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> --- include/uapi/linux/vfio.h | 149 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 149 insertions(+) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 9e843a147ead..135a1d3fa111 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -306,6 +306,155 @@ struct vfio_region_info_cap_type { #define VFIO_REGION_TYPE_GFX (1) #define VFIO_REGION_TYPE_CCW (2) +/* Migration region type and sub-type */ +#define VFIO_REGION_TYPE_MIGRATION (3) +#define VFIO_REGION_SUBTYPE_MIGRATION (1) + +/** + * Structure vfio_device_migration_info is placed at 0th offset of + * VFIO_REGION_SUBTYPE_MIGRATION region to get/set VFIO device related migration + * information. Field accesses from this structure are only supported at their + * native width and alignment, otherwise the result is undefined and vendor + * drivers should return an error. + * + * device_state: (read/write) + * To indicate vendor driver the state VFIO device should be transitioned + * to. If device state transition fails, write on this field return error. + * It consists of 3 bits: + * - If bit 0 set, indicates _RUNNING state. When its reset, that indicates + * _STOPPED state. When device is changed to _STOPPED, driver should stop + * device before write() returns. + * - If bit 1 set, indicates _SAVING state. + * - If bit 2 set, indicates _RESUMING state. + * Bits 3 - 31 are reserved for future use. User should perform + * read-modify-write operation on this field. + * _SAVING and _RESUMING bits set at the same time is invalid state. + * + * pending bytes: (read only) + * Number of pending bytes yet to be migrated from vendor driver + * + * data_offset: (read only) + * User application should read data_offset in migration region from where + * user application should read device data during _SAVING state or write + * device data during _RESUMING state or read dirty pages bitmap. See below + * for detail of sequence to be followed. + * + * data_size: (read/write) + * User application should read data_size to get size of data copied in + * migration region during _SAVING state and write size of data copied in + * migration region during _RESUMING state. + * + * start_pfn: (write only) + * Start address pfn to get bitmap of dirty pages from vendor driver duing + * _SAVING state. + * + * page_size: (write only) + * User application should write the page_size of pfn. + * + * total_pfns: (write only) + * Total pfn count from start_pfn for which dirty bitmap is requested. + * + * copied_pfns: (read only) + * pfn count for which dirty bitmap is copied to migration region. + * Vendor driver should copy the bitmap with bits set only for pages to be + * marked dirty in migration region. + * - Vendor driver should return VFIO_DEVICE_DIRTY_PFNS_NONE if none of the + * pages are dirty in requested range or rest of the range. + * - Vendor driver should return VFIO_DEVICE_DIRTY_PFNS_ALL to mark all + * pages dirty in the given range or rest of the range. + * - Vendor driver should return pfn count for which bitmap is written in + * the region. + * + * Migration region looks like: + * ------------------------------------------------------------------ + * |vfio_device_migration_info| data section | + * | | /////////////////////////////// | + * ------------------------------------------------------------------ + * ^ ^ ^ + * offset 0-trapped part data_offset data_size + * + * Data section is always followed by vfio_device_migration_info structure + * in the region, so data_offset will always be non-0. Offset from where data + * is copied is decided by kernel driver, data section can be trapped or + * mapped or partitioned, depending on how kernel driver defines data section. + * Data section partition can be defined as mapped by sparse mmap capability. + * If mmapped, then data_offset should be page aligned, where as initial section + * which contain vfio_device_migration_info structure might not end at offset + * which is page aligned. + * Data_offset can be same or different for device data and dirty pages bitmap. + * Vendor driver should decide whether to partition data section and how to + * partition the data section. Vendor driver should return data_offset + * accordingly. + * + * Sequence to be followed for _SAVING|_RUNNING device state or pre-copy phase + * and for _SAVING device state or stop-and-copy phase: + * a. read pending_bytes. If pending_bytes > 0, go through below steps. + * b. read data_offset, indicates kernel driver to write data to staging buffer. + * c. read data_size, amount of data in bytes written by vendor driver in + * migration region. + * d. read data_size bytes of data from data_offset in the migration region. + * e. process data. + * f. Loop through a to e. + * + * To copy system memory content during migration, vendor driver should be able + * to report system memory pages which are dirtied by that driver. For such + * dirty page reporting, user application should query for a range of GFNs + * relative to device address space (IOVA), then vendor driver should provide + * the bitmap of pages from this range which are dirtied by him through + * migration region where each bit represents a page and bit set to 1 represents + * that the page is dirty. + * User space application should take care of copying content of system memory + * for those pages. + * + * Steps to get dirty page bitmap: + * a. write start_pfn, page_size and total_pfns. + * b. read copied_pfns. Vendor driver should take one of the below action: + * - Vendor driver should return VFIO_DEVICE_DIRTY_PFNS_NONE if driver + * doesn't have any page to report dirty in given range or rest of the + * range. Exit the loop. + * - Vendor driver should return VFIO_DEVICE_DIRTY_PFNS_ALL to mark all + * pages dirty for given range or rest of the range. User space + * application mark all pages in the range as dirty and exit the loop. + * - Vendor driver should return copied_pfns and provide bitmap for + * copied_pfn in migration region. + * c. read data_offset, where vendor driver has written bitmap. + * d. read bitmap from the migration region from data_offset. + * e. Iterate through steps a to d while (total copied_pfns < total_pfns) + * + * Sequence to be followed while _RESUMING device state: + * While data for this device is available, repeat below steps: + * a. read data_offset from where user application should write data. + * b. write data of data_size to migration region from data_offset. + * c. write data_size which indicates vendor driver that data is written in + * staging buffer. + * + * For user application, data is opaque. User should write data in the same + * order as received. + */ + +struct vfio_device_migration_info { + __u32 device_state; /* VFIO device state */ +#define VFIO_DEVICE_STATE_RUNNING (1 << 0) +#define VFIO_DEVICE_STATE_SAVING (1 << 1) +#define VFIO_DEVICE_STATE_RESUMING (1 << 2) +#define VFIO_DEVICE_STATE_MASK (VFIO_DEVICE_STATE_RUNNING | \ + VFIO_DEVICE_STATE_SAVING | \ + VFIO_DEVICE_STATE_RESUMING) +#define VFIO_DEVICE_STATE_INVALID (VFIO_DEVICE_STATE_SAVING | \ + VFIO_DEVICE_STATE_RESUMING) + __u32 reserved; + __u64 pending_bytes; + __u64 data_offset; + __u64 data_size; + __u64 start_pfn; + __u64 page_size; + __u64 total_pfns; + __u64 copied_pfns; +#define VFIO_DEVICE_DIRTY_PFNS_NONE (0) +#define VFIO_DEVICE_DIRTY_PFNS_ALL (~0ULL) +} __attribute__((packed)); + + /* sub-types for VFIO_REGION_TYPE_PCI_* */ /* 8086 vendor PCI sub-types */ -- 2.17.1
