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xen_shm_machdep.c revision 1.11.2.1
      1  1.11.2.1  christos /*      $NetBSD: xen_shm_machdep.c,v 1.11.2.1 2019/06/10 22:06:56 christos Exp $      */
      2       1.2    bouyer 
      3       1.2    bouyer /*
      4       1.2    bouyer  * Copyright (c) 2006 Manuel Bouyer.
      5       1.2    bouyer  *
      6       1.2    bouyer  * Redistribution and use in source and binary forms, with or without
      7       1.2    bouyer  * modification, are permitted provided that the following conditions
      8       1.2    bouyer  * are met:
      9       1.2    bouyer  * 1. Redistributions of source code must retain the above copyright
     10       1.2    bouyer  *    notice, this list of conditions and the following disclaimer.
     11       1.2    bouyer  * 2. Redistributions in binary form must reproduce the above copyright
     12       1.2    bouyer  *    notice, this list of conditions and the following disclaimer in the
     13       1.2    bouyer  *    documentation and/or other materials provided with the distribution.
     14       1.2    bouyer  *
     15       1.2    bouyer  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     16       1.2    bouyer  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     17       1.2    bouyer  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     18       1.2    bouyer  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     19       1.2    bouyer  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     20       1.2    bouyer  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21       1.2    bouyer  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22       1.2    bouyer  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23       1.2    bouyer  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     24       1.2    bouyer  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25       1.2    bouyer  */
     26       1.2    bouyer 
     27       1.3    bouyer #include <sys/cdefs.h>
     28  1.11.2.1  christos __KERNEL_RCSID(0, "$NetBSD: xen_shm_machdep.c,v 1.11.2.1 2019/06/10 22:06:56 christos Exp $");
     29       1.3    bouyer 
     30       1.2    bouyer #include <sys/types.h>
     31       1.2    bouyer #include <sys/param.h>
     32       1.2    bouyer #include <sys/systm.h>
     33       1.2    bouyer #include <sys/queue.h>
     34       1.2    bouyer #include <sys/vmem.h>
     35       1.2    bouyer #include <sys/kernel.h>
     36       1.2    bouyer #include <uvm/uvm.h>
     37       1.2    bouyer 
     38       1.2    bouyer #include <machine/pmap.h>
     39       1.2    bouyer #include <xen/hypervisor.h>
     40       1.2    bouyer #include <xen/xen.h>
     41       1.2    bouyer #include <xen/evtchn.h>
     42       1.2    bouyer #include <xen/xen_shm.h>
     43       1.2    bouyer 
     44       1.2    bouyer /*
     45  1.11.2.1  christos  * Helper routines for the backend drivers. This implements the necessary
     46  1.11.2.1  christos  * functions to map a bunch of pages from foreign domains into our kernel VM
     47       1.2    bouyer  * space, do I/O to it, and unmap it.
     48       1.2    bouyer  *
     49       1.9       jym  * At boot time, we grab some kernel VM space that we'll use to map the foreign
     50  1.11.2.1  christos  * pages. We also maintain a virtual-to-machine mapping table to give back
     51       1.2    bouyer  * the appropriate address to bus_dma if requested.
     52  1.11.2.1  christos  *
     53       1.2    bouyer  * If no more VM space is available, we return an error. The caller can then
     54       1.2    bouyer  * register a callback which will be called when the required VM space is
     55       1.2    bouyer  * available.
     56       1.2    bouyer  */
     57       1.2    bouyer 
     58       1.8       snj /* Grab enough VM space to map an entire vbd ring. */
     59       1.2    bouyer /* Xen3 linux guests seems to eat more pages, gives enough for 10 vbd rings */
     60       1.2    bouyer #define BLKIF_RING_SIZE __RING_SIZE((blkif_sring_t *)0, PAGE_SIZE)
     61       1.2    bouyer #define XENSHM_NPAGES (BLKIF_RING_SIZE * (BLKIF_MAX_SEGMENTS_PER_REQUEST + 1) * 10)
     62       1.2    bouyer 
     63       1.2    bouyer /* vm space management */
     64  1.11.2.1  christos static vmem_t *xen_shm_arena __read_mostly;
     65       1.2    bouyer 
     66       1.2    bouyer /* callbacks are registered in a FIFO list. */
     67       1.2    bouyer static SIMPLEQ_HEAD(xen_shm_callback_head, xen_shm_callback_entry)
     68       1.2    bouyer     xen_shm_callbacks;
     69  1.11.2.1  christos 
     70       1.2    bouyer struct xen_shm_callback_entry {
     71       1.2    bouyer 	SIMPLEQ_ENTRY(xen_shm_callback_entry) xshmc_entries;
     72       1.2    bouyer 	int (*xshmc_callback)(void *); /* our callback */
     73       1.2    bouyer 	void *xshmc_arg; /* cookie passed to the callback */
     74       1.2    bouyer };
     75  1.11.2.1  christos 
     76       1.2    bouyer /* a pool of struct xen_shm_callback_entry */
     77       1.2    bouyer static struct pool xen_shm_callback_pool;
     78       1.2    bouyer 
     79       1.2    bouyer #ifdef DEBUG
     80       1.2    bouyer /* for ratecheck(9) */
     81       1.2    bouyer static struct timeval xen_shm_errintvl = { 60, 0 };  /* a minute, each */
     82       1.2    bouyer #endif
     83       1.2    bouyer 
     84       1.2    bouyer void
     85       1.5    cegger xen_shm_init(void)
     86       1.2    bouyer {
     87  1.11.2.1  christos 	vaddr_t xen_shm_base_address;
     88  1.11.2.1  christos 	vaddr_t xen_shm_end_address;
     89  1.11.2.1  christos 	u_long xen_shm_base_address_pg;
     90  1.11.2.1  christos 	vsize_t xen_shm_size;
     91  1.11.2.1  christos 
     92       1.2    bouyer 	SIMPLEQ_INIT(&xen_shm_callbacks);
     93       1.2    bouyer 	pool_init(&xen_shm_callback_pool, sizeof(struct xen_shm_callback_entry),
     94       1.2    bouyer 	    0, 0, 0, "xshmc", NULL, IPL_VM);
     95       1.2    bouyer 	/* ensure we'll always get items */
     96       1.2    bouyer 	if (pool_prime(&xen_shm_callback_pool,
     97       1.2    bouyer 	    PAGE_SIZE / sizeof(struct xen_shm_callback_entry)) != 0) {
     98       1.2    bouyer 		panic("xen_shm_init can't prime pool");
     99       1.2    bouyer 	}
    100       1.2    bouyer 
    101  1.11.2.1  christos 	xen_shm_size = (XENSHM_NPAGES * PAGE_SIZE);
    102  1.11.2.1  christos 
    103       1.2    bouyer 	xen_shm_base_address = uvm_km_alloc(kernel_map, xen_shm_size, 0,
    104       1.2    bouyer 	    UVM_KMF_VAONLY);
    105       1.2    bouyer 	xen_shm_end_address = xen_shm_base_address + xen_shm_size;
    106       1.2    bouyer 	xen_shm_base_address_pg = xen_shm_base_address >> PAGE_SHIFT;
    107       1.2    bouyer 	if (xen_shm_base_address == 0) {
    108       1.2    bouyer 		panic("xen_shm_init no VM space");
    109       1.2    bouyer 	}
    110  1.11.2.1  christos 	xen_shm_arena = vmem_create("xen_shm", xen_shm_base_address_pg,
    111       1.2    bouyer 	    (xen_shm_end_address >> PAGE_SHIFT) - 1 - xen_shm_base_address_pg,
    112       1.2    bouyer 	    1, NULL, NULL, NULL, 1, VM_NOSLEEP, IPL_VM);
    113       1.2    bouyer 	if (xen_shm_arena == NULL) {
    114       1.2    bouyer 		panic("xen_shm_init no arena");
    115       1.2    bouyer 	}
    116       1.2    bouyer }
    117       1.2    bouyer 
    118       1.2    bouyer int
    119       1.2    bouyer xen_shm_map(int nentries, int domid, grant_ref_t *grefp, vaddr_t *vap,
    120       1.2    bouyer     grant_handle_t *handlep, int flags)
    121       1.2    bouyer {
    122       1.2    bouyer 	gnttab_map_grant_ref_t op[XENSHM_MAX_PAGES_PER_REQUEST];
    123  1.11.2.1  christos 	vmem_addr_t new_va_pg;
    124  1.11.2.1  christos 	vaddr_t new_va;
    125  1.11.2.1  christos 	int ret, i, s;
    126       1.2    bouyer 
    127       1.2    bouyer #ifdef DIAGNOSTIC
    128       1.2    bouyer 	if (nentries > XENSHM_MAX_PAGES_PER_REQUEST) {
    129  1.11.2.1  christos 		panic("xen_shm_map: %d entries", nentries);
    130       1.2    bouyer 	}
    131       1.2    bouyer #endif
    132  1.11.2.1  christos 
    133      1.11  jdolecek 	/* XXXSMP */
    134       1.2    bouyer 	s = splvm(); /* splvm is the lowest level blocking disk and net IRQ */
    135  1.11.2.1  christos 
    136       1.2    bouyer 	/*
    137  1.11.2.1  christos 	 * If a driver is waiting for resources, don't try to allocate
    138       1.2    bouyer 	 * yet. This is to avoid a flood of small requests stalling large
    139       1.2    bouyer 	 * ones.
    140       1.2    bouyer 	 */
    141       1.2    bouyer 	if (__predict_false(SIMPLEQ_FIRST(&xen_shm_callbacks) != NULL) &&
    142       1.2    bouyer 	    (flags & XSHM_CALLBACK) == 0) {
    143       1.2    bouyer 		splx(s);
    144       1.2    bouyer #ifdef DEBUG
    145  1.11.2.1  christos 		static struct timeval lasttime;
    146       1.2    bouyer 		if (ratecheck(&lasttime, &xen_shm_errintvl))
    147       1.2    bouyer 			printf("xen_shm_map: ENOMEM1\n");
    148       1.2    bouyer #endif
    149       1.2    bouyer 		return ENOMEM;
    150       1.2    bouyer 	}
    151  1.11.2.1  christos 
    152  1.11.2.1  christos 	/* Allocate the needed virtual space. */
    153      1.10    dyoung 	if (vmem_alloc(xen_shm_arena, nentries,
    154      1.10    dyoung 	    VM_INSTANTFIT | VM_NOSLEEP, &new_va_pg) != 0) {
    155       1.2    bouyer 		splx(s);
    156       1.2    bouyer #ifdef DEBUG
    157  1.11.2.1  christos 		static struct timeval lasttime;
    158       1.2    bouyer 		if (ratecheck(&lasttime, &xen_shm_errintvl))
    159       1.2    bouyer 			printf("xen_shm_map: ENOMEM\n");
    160       1.2    bouyer #endif
    161       1.2    bouyer 		return ENOMEM;
    162       1.2    bouyer 	}
    163       1.2    bouyer 	splx(s);
    164       1.2    bouyer 
    165       1.2    bouyer 	new_va = new_va_pg << PAGE_SHIFT;
    166       1.2    bouyer 	for (i = 0; i < nentries; i++) {
    167       1.2    bouyer 		op[i].host_addr = new_va + i * PAGE_SIZE;
    168       1.2    bouyer 		op[i].dom = domid;
    169       1.2    bouyer 		op[i].ref = grefp[i];
    170       1.2    bouyer 		op[i].flags = GNTMAP_host_map |
    171       1.2    bouyer 		    ((flags & XSHM_RO) ? GNTMAP_readonly : 0);
    172       1.2    bouyer 	}
    173  1.11.2.1  christos 
    174  1.11.2.1  christos 	ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, op, nentries);
    175  1.11.2.1  christos 	if (__predict_false(ret)) {
    176       1.2    bouyer 		panic("xen_shm_map: HYPERVISOR_grant_table_op failed");
    177  1.11.2.1  christos 	}
    178  1.11.2.1  christos 
    179       1.2    bouyer 	for (i = 0; i < nentries; i++) {
    180       1.2    bouyer 		if (__predict_false(op[i].status))
    181       1.2    bouyer 			return op[i].status;
    182       1.2    bouyer 		handlep[i] = op[i].handle;
    183       1.2    bouyer 	}
    184  1.11.2.1  christos 
    185       1.2    bouyer 	*vap = new_va;
    186       1.2    bouyer 	return 0;
    187       1.2    bouyer }
    188       1.2    bouyer 
    189       1.2    bouyer void
    190       1.2    bouyer xen_shm_unmap(vaddr_t va, int nentries, grant_handle_t *handlep)
    191       1.2    bouyer {
    192       1.2    bouyer 	gnttab_unmap_grant_ref_t op[XENSHM_MAX_PAGES_PER_REQUEST];
    193       1.2    bouyer 	struct xen_shm_callback_entry *xshmc;
    194  1.11.2.1  christos 	int ret, i, s;
    195       1.2    bouyer 
    196       1.2    bouyer #ifdef DIAGNOSTIC
    197       1.2    bouyer 	if (nentries > XENSHM_MAX_PAGES_PER_REQUEST) {
    198  1.11.2.1  christos 		panic("xen_shm_unmap: %d entries", nentries);
    199       1.2    bouyer 	}
    200       1.2    bouyer #endif
    201       1.2    bouyer 
    202       1.2    bouyer 	for (i = 0; i < nentries; i++) {
    203       1.2    bouyer 		op[i].host_addr = va + i * PAGE_SIZE;
    204       1.2    bouyer 		op[i].dev_bus_addr = 0;
    205       1.2    bouyer 		op[i].handle = handlep[i];
    206       1.2    bouyer 	}
    207  1.11.2.1  christos 
    208       1.2    bouyer 	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
    209       1.2    bouyer 	    op, nentries);
    210  1.11.2.1  christos 	if (__predict_false(ret)) {
    211       1.2    bouyer 		panic("xen_shm_unmap: unmap failed");
    212  1.11.2.1  christos 	}
    213  1.11.2.1  christos 
    214       1.2    bouyer 	va = va >> PAGE_SHIFT;
    215  1.11.2.1  christos 
    216      1.11  jdolecek 	/* XXXSMP */
    217       1.2    bouyer 	s = splvm(); /* splvm is the lowest level blocking disk and net IRQ */
    218  1.11.2.1  christos 
    219       1.2    bouyer 	vmem_free(xen_shm_arena, va, nentries);
    220       1.2    bouyer 	while (__predict_false((xshmc = SIMPLEQ_FIRST(&xen_shm_callbacks))
    221       1.2    bouyer 	    != NULL)) {
    222       1.2    bouyer 		SIMPLEQ_REMOVE_HEAD(&xen_shm_callbacks, xshmc_entries);
    223       1.2    bouyer 		splx(s);
    224       1.2    bouyer 		if (xshmc->xshmc_callback(xshmc->xshmc_arg) == 0) {
    225       1.2    bouyer 			/* callback succeeded */
    226      1.11  jdolecek 			s = splvm(); /* XXXSMP */
    227       1.2    bouyer 			pool_put(&xen_shm_callback_pool, xshmc);
    228       1.2    bouyer 		} else {
    229  1.11.2.1  christos 			/* callback failed, probably out of resources */
    230      1.11  jdolecek 			s = splvm(); /* XXXSMP */
    231       1.2    bouyer 			SIMPLEQ_INSERT_TAIL(&xen_shm_callbacks, xshmc,
    232  1.11.2.1  christos 			    xshmc_entries);
    233       1.2    bouyer 			break;
    234       1.2    bouyer 		}
    235       1.2    bouyer 	}
    236  1.11.2.1  christos 
    237       1.2    bouyer 	splx(s);
    238       1.2    bouyer }
    239       1.2    bouyer 
    240       1.2    bouyer int
    241       1.2    bouyer xen_shm_callback(int (*callback)(void *), void *arg)
    242       1.2    bouyer {
    243       1.2    bouyer 	struct xen_shm_callback_entry *xshmc;
    244       1.2    bouyer 	int s;
    245       1.2    bouyer 
    246      1.11  jdolecek 	s = splvm(); /* XXXSMP */
    247       1.2    bouyer 	xshmc = pool_get(&xen_shm_callback_pool, PR_NOWAIT);
    248       1.2    bouyer 	if (xshmc == NULL) {
    249       1.2    bouyer 		splx(s);
    250       1.2    bouyer 		return ENOMEM;
    251       1.2    bouyer 	}
    252       1.2    bouyer 	xshmc->xshmc_arg = arg;
    253       1.2    bouyer 	xshmc->xshmc_callback = callback;
    254       1.2    bouyer 	SIMPLEQ_INSERT_TAIL(&xen_shm_callbacks, xshmc, xshmc_entries);
    255       1.2    bouyer 	splx(s);
    256       1.2    bouyer 	return 0;
    257       1.2    bouyer }
    258