/* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #ifndef __XEN_BLKIF__BACKEND__COMMON_H__ #define __XEN_BLKIF__BACKEND__COMMON_H__ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern unsigned int xen_blkif_max_ring_order; extern unsigned int xenblk_max_queues; /* * This is the maximum number of segments that would be allowed in indirect * requests. This value will also be passed to the frontend. */ #define MAX_INDIRECT_SEGMENTS 256 /* * Xen use 4K pages. The guest may use different page size (4K or 64K) * Number of Xen pages per segment */ #define XEN_PAGES_PER_SEGMENT (PAGE_SIZE / XEN_PAGE_SIZE) #define XEN_PAGES_PER_INDIRECT_FRAME \ (XEN_PAGE_SIZE/sizeof(struct blkif_request_segment)) #define SEGS_PER_INDIRECT_FRAME \ (XEN_PAGES_PER_INDIRECT_FRAME / XEN_PAGES_PER_SEGMENT) #define MAX_INDIRECT_PAGES \ ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME) #define INDIRECT_PAGES(_segs) DIV_ROUND_UP(_segs, XEN_PAGES_PER_INDIRECT_FRAME) /* Not a real protocol. Used to generate ring structs which contain * the elements common to all protocols only. This way we get a * compiler-checkable way to use common struct elements, so we can * avoid using switch(protocol) in a number of places. */ struct blkif_common_request { char dummy; }; /* i386 protocol version */ struct blkif_x86_32_request_rw { uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; } __attribute__((__packed__)); struct blkif_x86_32_request_discard { uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */ blkif_vdev_t _pad1; /* was "handle" for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; } __attribute__((__packed__)); struct blkif_x86_32_request_other { uint8_t _pad1; blkif_vdev_t _pad2; uint64_t id; /* private guest value, echoed in resp */ } __attribute__((__packed__)); struct blkif_x86_32_request_indirect { uint8_t indirect_op; uint16_t nr_segments; uint64_t id; blkif_sector_t sector_number; blkif_vdev_t handle; uint16_t _pad1; grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST]; /* * The maximum number of indirect segments (and pages) that will * be used is determined by MAX_INDIRECT_SEGMENTS, this value * is also exported to the guest (via xenstore * feature-max-indirect-segments entry), so the frontend knows how * many indirect segments the backend supports. */ uint64_t _pad2; /* make it 64 byte aligned */ } __attribute__((__packed__)); struct blkif_x86_32_request { uint8_t operation; /* BLKIF_OP_??? */ union { struct blkif_x86_32_request_rw rw; struct blkif_x86_32_request_discard discard; struct blkif_x86_32_request_other other; struct blkif_x86_32_request_indirect indirect; } u; } __attribute__((__packed__)); /* x86_64 protocol version */ struct blkif_x86_64_request_rw { uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */ uint64_t id; blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; } __attribute__((__packed__)); struct blkif_x86_64_request_discard { uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */ blkif_vdev_t _pad1; /* was "handle" for read/write requests */ uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */ uint64_t id; blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; } __attribute__((__packed__)); struct blkif_x86_64_request_other { uint8_t _pad1; blkif_vdev_t _pad2; uint32_t _pad3; /* offsetof(blkif_..,u.discard.id)==8 */ uint64_t id; /* private guest value, echoed in resp */ } __attribute__((__packed__)); struct blkif_x86_64_request_indirect { uint8_t indirect_op; uint16_t nr_segments; uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */ uint64_t id; blkif_sector_t sector_number; blkif_vdev_t handle; uint16_t _pad2; grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST]; /* * The maximum number of indirect segments (and pages) that will * be used is determined by MAX_INDIRECT_SEGMENTS, this value * is also exported to the guest (via xenstore * feature-max-indirect-segments entry), so the frontend knows how * many indirect segments the backend supports. */ uint32_t _pad3; /* make it 64 byte aligned */ } __attribute__((__packed__)); struct blkif_x86_64_request { uint8_t operation; /* BLKIF_OP_??? */ union { struct blkif_x86_64_request_rw rw; struct blkif_x86_64_request_discard discard; struct blkif_x86_64_request_other other; struct blkif_x86_64_request_indirect indirect; } u; } __attribute__((__packed__)); DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_response); DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_response __packed); DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_response); union blkif_back_rings { struct blkif_back_ring native; struct blkif_common_back_ring common; struct blkif_x86_32_back_ring x86_32; struct blkif_x86_64_back_ring x86_64; }; enum blkif_protocol { BLKIF_PROTOCOL_NATIVE = 1, BLKIF_PROTOCOL_X86_32 = 2, BLKIF_PROTOCOL_X86_64 = 3, }; /* * Default protocol if the frontend doesn't specify one. */ #ifdef CONFIG_X86 # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_X86_32 #else # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_NATIVE #endif struct xen_vbd { /* What the domain refers to this vbd as. */ blkif_vdev_t handle; /* Non-zero -> read-only */ unsigned char readonly; /* VDISK_xxx */ unsigned char type; /* phys device that this vbd maps to. */ u32 pdevice; struct block_device *bdev; /* Cached size parameter. */ sector_t size; unsigned int flush_support:1; unsigned int discard_secure:1; /* Connect-time cached feature_persistent parameter value */ unsigned int feature_gnt_persistent_parm:1; /* Persistent grants feature negotiation result */ unsigned int feature_gnt_persistent:1; unsigned int overflow_max_grants:1; }; struct backend_info; /* Number of requests that we can fit in a ring */ #define XEN_BLKIF_REQS_PER_PAGE 32 struct persistent_gnt { struct page *page; grant_ref_t gnt; grant_handle_t handle; unsigned long last_used; bool active; struct rb_node node; struct list_head remove_node; }; /* Per-ring information. */ struct xen_blkif_ring { /* Physical parameters of the comms window. */ unsigned int irq; union blkif_back_rings blk_rings; void *blk_ring; /* Private fields. */ spinlock_t blk_ring_lock; wait_queue_head_t wq; atomic_t inflight; bool active; /* One thread per blkif ring. */ struct task_struct *xenblkd; unsigned int waiting_reqs; /* List of all 'pending_req' available */ struct list_head pending_free; /* And its spinlock. */ spinlock_t pending_free_lock; wait_queue_head_t pending_free_wq; /* Tree to store persistent grants. */ struct rb_root persistent_gnts; unsigned int persistent_gnt_c; atomic_t persistent_gnt_in_use; unsigned long next_lru; /* Statistics. */ unsigned long st_print; unsigned long long st_rd_req; unsigned long long st_wr_req; unsigned long long st_oo_req; unsigned long long st_f_req; unsigned long long st_ds_req; unsigned long long st_rd_sect; unsigned long long st_wr_sect; /* Used by the kworker that offload work from the persistent purge. */ struct list_head persistent_purge_list; struct work_struct persistent_purge_work; /* Buffer of free pages to map grant refs. */ struct gnttab_page_cache free_pages; struct work_struct free_work; /* Thread shutdown wait queue. */ wait_queue_head_t shutdown_wq; struct xen_blkif *blkif; }; struct xen_blkif { /* Unique identifier for this interface. */ domid_t domid; unsigned int handle; /* Comms information. */ enum blkif_protocol blk_protocol; /* The VBD attached to this interface. */ struct xen_vbd vbd; /* Back pointer to the backend_info. */ struct backend_info *be; atomic_t refcnt; /* for barrier (drain) requests */ struct completion drain_complete; atomic_t drain; struct work_struct free_work; unsigned int nr_ring_pages; bool multi_ref; /* All rings for this device. */ struct xen_blkif_ring *rings; unsigned int nr_rings; unsigned long buffer_squeeze_end; }; struct seg_buf { unsigned long offset; unsigned int nsec; }; struct grant_page { struct page *page; struct persistent_gnt *persistent_gnt; grant_handle_t handle; grant_ref_t gref; }; /* * Each outstanding request that we've passed to the lower device layers has a * 'pending_req' allocated to it. Each buffer_head that completes decrements * the pendcnt towards zero. When it hits zero, the specified domain has a * response queued for it, with the saved 'id' passed back. */ struct pending_req { struct xen_blkif_ring *ring; u64 id; int nr_segs; atomic_t pendcnt; unsigned short operation; int status; struct list_head free_list; struct grant_page *segments[MAX_INDIRECT_SEGMENTS]; /* Indirect descriptors */ struct grant_page *indirect_pages[MAX_INDIRECT_PAGES]; struct seg_buf seg[MAX_INDIRECT_SEGMENTS]; struct bio *biolist[MAX_INDIRECT_SEGMENTS]; struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS]; struct page *unmap_pages[MAX_INDIRECT_SEGMENTS]; struct gntab_unmap_queue_data gnttab_unmap_data; }; #define vbd_sz(_v) bdev_nr_sectors((_v)->bdev) #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) #define xen_blkif_put(_b) \ do { \ if (atomic_dec_and_test(&(_b)->refcnt)) \ schedule_work(&(_b)->free_work);\ } while (0) struct phys_req { unsigned short dev; blkif_sector_t nr_sects; struct block_device *bdev; blkif_sector_t sector_number; }; int xen_blkif_interface_init(void); void xen_blkif_interface_fini(void); int xen_blkif_xenbus_init(void); void xen_blkif_xenbus_fini(void); irqreturn_t xen_blkif_be_int(int irq, void *dev_id); int xen_blkif_schedule(void *arg); int xen_blkif_purge_persistent(void *arg); void xen_blkbk_free_caches(struct xen_blkif_ring *ring); int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state); int xen_blkbk_barrier(struct xenbus_transaction xbt, struct backend_info *be, int state); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be); void xen_blkbk_unmap_purged_grants(struct work_struct *work); static inline void blkif_get_x86_32_req(struct blkif_request *dst, struct blkif_x86_32_request *src) { int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j; dst->operation = READ_ONCE(src->operation); switch (dst->operation) { case BLKIF_OP_READ: case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: case BLKIF_OP_FLUSH_DISKCACHE: dst->u.rw.nr_segments = src->u.rw.nr_segments; dst->u.rw.handle = src->u.rw.handle; dst->u.rw.id = src->u.rw.id; dst->u.rw.sector_number = src->u.rw.sector_number; barrier(); if (n > dst->u.rw.nr_segments) n = dst->u.rw.nr_segments; for (i = 0; i < n; i++) dst->u.rw.seg[i] = src->u.rw.seg[i]; break; case BLKIF_OP_DISCARD: dst->u.discard.flag = src->u.discard.flag; dst->u.discard.id = src->u.discard.id; dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break; case BLKIF_OP_INDIRECT: dst->u.indirect.indirect_op = src->u.indirect.indirect_op; dst->u.indirect.nr_segments = src->u.indirect.nr_segments; dst->u.indirect.handle = src->u.indirect.handle; dst->u.indirect.id = src->u.indirect.id; dst->u.indirect.sector_number = src->u.indirect.sector_number; barrier(); j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments)); for (i = 0; i < j; i++) dst->u.indirect.indirect_grefs[i] = src->u.indirect.indirect_grefs[i]; break; default: /* * Don't know how to translate this op. Only get the * ID so failure can be reported to the frontend. */ dst->u.other.id = src->u.other.id; break; } } static inline void blkif_get_x86_64_req(struct blkif_request *dst, struct blkif_x86_64_request *src) { int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j; dst->operation = READ_ONCE(src->operation); switch (dst->operation) { case BLKIF_OP_READ: case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: case BLKIF_OP_FLUSH_DISKCACHE: dst->u.rw.nr_segments = src->u.rw.nr_segments; dst->u.rw.handle = src->u.rw.handle; dst->u.rw.id = src->u.rw.id; dst->u.rw.sector_number = src->u.rw.sector_number; barrier(); if (n > dst->u.rw.nr_segments) n = dst->u.rw.nr_segments; for (i = 0; i < n; i++) dst->u.rw.seg[i] = src->u.rw.seg[i]; break; case BLKIF_OP_DISCARD: dst->u.discard.flag = src->u.discard.flag; dst->u.discard.id = src->u.discard.id; dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break; case BLKIF_OP_INDIRECT: dst->u.indirect.indirect_op = src->u.indirect.indirect_op; dst->u.indirect.nr_segments = src->u.indirect.nr_segments; dst->u.indirect.handle = src->u.indirect.handle; dst->u.indirect.id = src->u.indirect.id; dst->u.indirect.sector_number = src->u.indirect.sector_number; barrier(); j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments)); for (i = 0; i < j; i++) dst->u.indirect.indirect_grefs[i] = src->u.indirect.indirect_grefs[i]; break; default: /* * Don't know how to translate this op. Only get the * ID so failure can be reported to the frontend. */ dst->u.other.id = src->u.other.id; break; } } #endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */