diff options
Diffstat (limited to 'include/xen/interface/io')
| -rw-r--r-- | include/xen/interface/io/blkif.h | 36 | ||||
| -rw-r--r-- | include/xen/interface/io/netif.h | 53 |
2 files changed, 68 insertions, 21 deletions
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h index ae665ac59c3..c33e1c489eb 100644 --- a/include/xen/interface/io/blkif.h +++ b/include/xen/interface/io/blkif.h @@ -86,7 +86,7 @@ typedef uint64_t blkif_sector_t; * Interface%20manuals/100293068c.pdf * The backend can optionally provide three extra XenBus attributes to * further optimize the discard functionality: - * 'discard-aligment' - Devices that support discard functionality may + * 'discard-alignment' - Devices that support discard functionality may * internally allocate space in units that are bigger than the exported * logical block size. The discard-alignment parameter indicates how many bytes * the beginning of the partition is offset from the internal allocation unit's @@ -113,13 +113,13 @@ typedef uint64_t blkif_sector_t; * it's less than the number provided by the backend. The indirect_grefs field * in blkif_request_indirect should be filled by the frontend with the * grant references of the pages that are holding the indirect segments. - * This pages are filled with an array of blkif_request_segment_aligned - * that hold the information about the segments. The number of indirect - * pages to use is determined by the maximum number of segments - * a indirect request contains. Every indirect page can contain a maximum - * of 512 segments (PAGE_SIZE/sizeof(blkif_request_segment_aligned)), - * so to calculate the number of indirect pages to use we have to do - * ceil(indirect_segments/512). + * These pages are filled with an array of blkif_request_segment that hold the + * information about the segments. The number of indirect pages to use is + * determined by the number of segments an indirect request contains. Every + * indirect page can contain a maximum of + * (PAGE_SIZE / sizeof(struct blkif_request_segment)) segments, so to + * calculate the number of indirect pages to use we have to do + * ceil(indirect_segments / (PAGE_SIZE / sizeof(struct blkif_request_segment))). * * If a backend does not recognize BLKIF_OP_INDIRECT, it should *not* * create the "feature-max-indirect-segments" node! @@ -135,13 +135,12 @@ typedef uint64_t blkif_sector_t; #define BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST 8 -struct blkif_request_segment_aligned { - grant_ref_t gref; /* reference to I/O buffer frame */ - /* @first_sect: first sector in frame to transfer (inclusive). */ - /* @last_sect: last sector in frame to transfer (inclusive). */ - uint8_t first_sect, last_sect; - uint16_t _pad; /* padding to make it 8 bytes, so it's cache-aligned */ -} __attribute__((__packed__)); +struct blkif_request_segment { + grant_ref_t gref; /* reference to I/O buffer frame */ + /* @first_sect: first sector in frame to transfer (inclusive). */ + /* @last_sect: last sector in frame to transfer (inclusive). */ + uint8_t first_sect, last_sect; +}; struct blkif_request_rw { uint8_t nr_segments; /* number of segments */ @@ -151,12 +150,7 @@ struct blkif_request_rw { #endif 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 { - grant_ref_t gref; /* reference to I/O buffer frame */ - /* @first_sect: first sector in frame to transfer (inclusive). */ - /* @last_sect: last sector in frame to transfer (inclusive). */ - uint8_t first_sect, last_sect; - } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; } __attribute__((__packed__)); struct blkif_request_discard { diff --git a/include/xen/interface/io/netif.h b/include/xen/interface/io/netif.h index c50061db609..70054cc0708 100644 --- a/include/xen/interface/io/netif.h +++ b/include/xen/interface/io/netif.h @@ -51,6 +51,59 @@ */ /* + * Multiple transmit and receive queues: + * If supported, the backend will write the key "multi-queue-max-queues" to + * the directory for that vif, and set its value to the maximum supported + * number of queues. + * Frontends that are aware of this feature and wish to use it can write the + * key "multi-queue-num-queues", set to the number they wish to use, which + * must be greater than zero, and no more than the value reported by the backend + * in "multi-queue-max-queues". + * + * Queues replicate the shared rings and event channels. + * "feature-split-event-channels" may optionally be used when using + * multiple queues, but is not mandatory. + * + * Each queue consists of one shared ring pair, i.e. there must be the same + * number of tx and rx rings. + * + * For frontends requesting just one queue, the usual event-channel and + * ring-ref keys are written as before, simplifying the backend processing + * to avoid distinguishing between a frontend that doesn't understand the + * multi-queue feature, and one that does, but requested only one queue. + * + * Frontends requesting two or more queues must not write the toplevel + * event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys, + * instead writing those keys under sub-keys having the name "queue-N" where + * N is the integer ID of the queue for which those keys belong. Queues + * are indexed from zero. For example, a frontend with two queues and split + * event channels must write the following set of queue-related keys: + * + * /local/domain/1/device/vif/0/multi-queue-num-queues = "2" + * /local/domain/1/device/vif/0/queue-0 = "" + * /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>" + * /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>" + * /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>" + * /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>" + * /local/domain/1/device/vif/0/queue-1 = "" + * /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>" + * /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1" + * /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>" + * /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>" + * + * If there is any inconsistency in the XenStore data, the backend may + * choose not to connect any queues, instead treating the request as an + * error. This includes scenarios where more (or fewer) queues were + * requested than the frontend provided details for. + * + * Mapping of packets to queues is considered to be a function of the + * transmitting system (backend or frontend) and is not negotiated + * between the two. Guests are free to transmit packets on any queue + * they choose, provided it has been set up correctly. Guests must be + * prepared to receive packets on any queue they have requested be set up. + */ + +/* * "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum * offload off or on. If it is missing then the feature is assumed to be on. * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum |