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xen_shm_machdep.c revision 1.13.10.1 
      1 /*      $NetBSD: xen_shm_machdep.c,v 1.13.10.1 2020/04/20 11:29:01 bouyer Exp $      */
      2 
      3 /*
      4  * Copyright (c) 2006 Manuel Bouyer.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include <sys/cdefs.h>
     28 __KERNEL_RCSID(0, "$NetBSD: xen_shm_machdep.c,v 1.13.10.1 2020/04/20 11:29:01 bouyer Exp $");
     29 
     30 #include <sys/types.h>
     31 #include <sys/param.h>
     32 #include <sys/systm.h>
     33 #include <sys/queue.h>
     34 #include <sys/vmem.h>
     35 #include <sys/kernel.h>
     36 #include <uvm/uvm.h>
     37 
     38 #include <machine/pmap.h>
     39 #include <xen/hypervisor.h>
     40 #include <xen/xen.h>
     41 #include <xen/evtchn.h>
     42 #include <xen/xen_shm.h>
     43 
     44 /*
     45  * Helper routines for the backend drivers. This implements the necessary
     46  * functions to map a bunch of pages from foreign domains into our kernel VM
     47  * space, do I/O to it, and unmap it.
     48  *
     49  * At boot time, we grab some kernel VM space that we'll use to map the foreign
     50  * pages. We also maintain a virtual-to-machine mapping table to give back
     51  * the appropriate address to bus_dma if requested.
     52  *
     53  * If no more VM space is available, we return an error. The caller can then
     54  * register a callback which will be called when the required VM space is
     55  * available.
     56  */
     57 
     58 int
     59 xen_shm_map(int nentries, int domid, grant_ref_t *grefp, vaddr_t va,
     60     grant_handle_t *handlep, int flags)
     61 {
     62 	gnttab_map_grant_ref_t op[XENSHM_MAX_PAGES_PER_REQUEST];
     63 	int ret, i;
     64 
     65 #ifdef DIAGNOSTIC
     66 	if (nentries > XENSHM_MAX_PAGES_PER_REQUEST) {
     67 		panic("xen_shm_map: %d entries", nentries);
     68 	}
     69 #endif
     70 
     71 	for (i = 0; i < nentries; i++) {
     72 		op[i].host_addr = va + i * PAGE_SIZE;
     73 		op[i].dom = domid;
     74 		op[i].ref = grefp[i];
     75 		op[i].flags = GNTMAP_host_map |
     76 		    ((flags & XSHM_RO) ? GNTMAP_readonly : 0);
     77 	}
     78 
     79 	ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, op, nentries);
     80 	if (__predict_false(ret)) {
     81 		printf("%s: HYPERVISOR_grant_table_op failed\n", __func__);
     82 		return EINVAL;
     83 	}
     84 
     85 	for (i = 0; i < nentries; i++) {
     86 #ifdef DIAGNOSTIC
     87 		if (__predict_false(op[i].status))
     88 			panic("%s: op[%d] status %d", __func__, i,
     89 			    op[i].status);
     90 #endif
     91 		handlep[i] = op[i].handle;
     92 	}
     93 
     94 	return 0;
     95 }
     96 
     97 void
     98 xen_shm_unmap(vaddr_t va, int nentries, grant_handle_t *handlep)
     99 {
    100 	gnttab_unmap_grant_ref_t op[XENSHM_MAX_PAGES_PER_REQUEST];
    101 	int ret, i;
    102 
    103 #ifdef DIAGNOSTIC
    104 	if (nentries > XENSHM_MAX_PAGES_PER_REQUEST) {
    105 		panic("xen_shm_unmap: %d entries", nentries);
    106 	}
    107 #endif
    108 
    109 	for (i = 0; i < nentries; i++) {
    110 		op[i].host_addr = va + i * PAGE_SIZE;
    111 		op[i].dev_bus_addr = 0;
    112 		op[i].handle = handlep[i];
    113 	}
    114 
    115 	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
    116 	    op, nentries);
    117 	if (__predict_false(ret)) {
    118 		panic("xen_shm_unmap: unmap failed");
    119 	}
    120 }
    121