1 /* $NetBSD: xen_shm_machdep.c,v 1.16 2020/04/25 15:26:17 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 1.16 2020/04/25 15:26:17 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