[infiniband] Add support for SRP over Infiniband

SRP is the SCSI RDMA Protocol.  It allows for a method of SAN booting
whereby the target is responsible for reading and writing data using
Remote DMA directly to the initiator's memory.  The software initiator
merely sends and receives SCSI commands; it never has to touch the
actual data.

src/arch/i386/interface/pcbios/ib_srpboot.c

@@ -0,0 +1,63 @@
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <gpxe/sanboot.h>
+#include <int13.h>
+#include <gpxe/srp.h>
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+static int ib_srpboot ( const char *root_path ) {
+	struct scsi_device *scsi;
+	struct int13_drive *drive;
+	int rc;
+
+	scsi = zalloc ( sizeof ( *scsi ) );
+	if ( ! scsi ) {
+		rc = -ENOMEM;
+		goto err_alloc_scsi;
+	}
+	drive = zalloc ( sizeof ( *drive ) );
+	if ( ! drive ) {
+		rc = -ENOMEM;
+		goto err_alloc_drive;
+	}
+
+	if ( ( rc = srp_attach ( scsi, root_path ) ) != 0 ) {
+		printf ( "Could not attach IB_SRP device: %s\n",
+			 strerror ( rc ) );
+		goto err_attach;
+	}
+	if ( ( rc = init_scsidev ( scsi ) ) != 0 ) {
+		printf ( "Could not initialise IB_SRP device: %s\n",
+			 strerror ( rc ) );
+		goto err_init;
+	}
+
+	drive->blockdev = &scsi->blockdev;
+
+	register_int13_drive ( drive );
+	printf ( "Registered as BIOS drive %#02x\n", drive->drive );
+	printf ( "Booting from BIOS drive %#02x\n", drive->drive );
+	rc = int13_boot ( drive->drive );
+	printf ( "Boot failed\n" );
+
+	printf ( "Unregistering BIOS drive %#02x\n", drive->drive );
+	unregister_int13_drive ( drive );
+
+ err_init:
+	srp_detach ( scsi );
+ err_attach:
+	free ( drive );
+ err_alloc_drive:
+	free ( scsi );
+ err_alloc_scsi:
+	return rc;
+}
+
+struct sanboot_protocol ib_srp_sanboot_protocol __sanboot_protocol = {
+	.prefix = "ib_srp:",
+	.boot = ib_srpboot,
+};

src/config/general.h

@@ -62,6 +62,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 //#undef	SANBOOT_PROTO_ISCSI	/* iSCSI protocol */
 //#undef	SANBOOT_PROTO_AOE	/* AoE protocol */
+//#undef	SANBOOT_PROTO_IB_SRP	/* Infiniband SCSI RDMA protocol */
 
 /*
  * Name resolution modules

src/core/config.c

@@ -109,6 +109,9 @@ REQUIRE_OBJECT ( iscsiboot );
 #ifdef SANBOOT_PROTO_AOE
 REQUIRE_OBJECT ( aoeboot );
 #endif
+#ifdef SANBOOT_PROTO_IB_SRP
+REQUIRE_OBJECT ( ib_srpboot );
+#endif
 
 /*
  * Drag in all requested resolvers