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      1 /*	$NetBSD: vmid.c,v 1.2 2021/12/18 23:45:08 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright 2019 Advanced Micro Devices, Inc.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included in
     14  * all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  *
     24  * Authors: AMD
     25  *
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 __KERNEL_RCSID(0, "$NetBSD: vmid.c,v 1.2 2021/12/18 23:45:08 riastradh Exp $");
     30 
     31 #include "mod_vmid.h"
     32 
     33 struct core_vmid {
     34 	struct mod_vmid public;
     35 	struct dc *dc;
     36 
     37 	unsigned int num_vmid;
     38 	unsigned int num_vmids_available;
     39 	uint64_t ptb_assigned_to_vmid[MAX_VMID];
     40 	struct dc_virtual_addr_space_config base_config;
     41 };
     42 
     43 #define MOD_VMID_TO_CORE(mod_vmid)\
     44 		container_of(mod_vmid, struct core_vmid, public)
     45 
     46 static void add_ptb_to_table(struct core_vmid *core_vmid, unsigned int vmid, uint64_t ptb)
     47 {
     48 	core_vmid->ptb_assigned_to_vmid[vmid] = ptb;
     49 	core_vmid->num_vmids_available--;
     50 }
     51 
     52 static void clear_entry_from_vmid_table(struct core_vmid *core_vmid, unsigned int vmid)
     53 {
     54 	core_vmid->ptb_assigned_to_vmid[vmid] = 0;
     55 	core_vmid->num_vmids_available++;
     56 }
     57 
     58 static void evict_vmids(struct core_vmid *core_vmid)
     59 {
     60 	int i;
     61 	uint16_t ord = dc_get_vmid_use_vector(core_vmid->dc);
     62 
     63 	// At this point any positions with value 0 are unused vmids, evict them
     64 	for (i = 1; i < core_vmid->num_vmid; i++) {
     65 		if (ord & (1u << i))
     66 			clear_entry_from_vmid_table(core_vmid, i);
     67 	}
     68 }
     69 
     70 // Return value of -1 indicates vmid table unitialized or ptb dne in the table
     71 static int get_existing_vmid_for_ptb(struct core_vmid *core_vmid, uint64_t ptb)
     72 {
     73 	int i;
     74 
     75 	for (i = 0; i < core_vmid->num_vmid; i++) {
     76 		if (core_vmid->ptb_assigned_to_vmid[i] == ptb)
     77 			return i;
     78 	}
     79 
     80 	return -1;
     81 }
     82 
     83 // Expected to be called only when there's an available vmid
     84 static int get_next_available_vmid(struct core_vmid *core_vmid)
     85 {
     86 	int i;
     87 
     88 	for (i = 1; i < core_vmid->num_vmid; i++) {
     89 		if (core_vmid->ptb_assigned_to_vmid[i] == 0)
     90 			return i;
     91 	}
     92 
     93 	return -1;
     94 }
     95 
     96 uint8_t mod_vmid_get_for_ptb(struct mod_vmid *mod_vmid, uint64_t ptb)
     97 {
     98 	struct core_vmid *core_vmid = MOD_VMID_TO_CORE(mod_vmid);
     99 	unsigned int vmid = 0;
    100 
    101 	// Physical address gets vmid 0
    102 	if (ptb == 0)
    103 		return 0;
    104 
    105 	vmid = get_existing_vmid_for_ptb(core_vmid, ptb);
    106 
    107 	if (vmid == -1) {
    108 		struct dc_virtual_addr_space_config va_config = core_vmid->base_config;
    109 
    110 		va_config.page_table_base_addr = ptb;
    111 
    112 		if (core_vmid->num_vmids_available == 0)
    113 			evict_vmids(core_vmid);
    114 
    115 		vmid = get_next_available_vmid(core_vmid);
    116 		add_ptb_to_table(core_vmid, vmid, ptb);
    117 
    118 		dc_setup_vm_context(core_vmid->dc, &va_config, vmid);
    119 	}
    120 
    121 	return vmid;
    122 }
    123 
    124 void mod_vmid_reset(struct mod_vmid *mod_vmid)
    125 {
    126 	struct core_vmid *core_vmid = MOD_VMID_TO_CORE(mod_vmid);
    127 
    128 	core_vmid->num_vmids_available = core_vmid->num_vmid - 1;
    129 	memset(core_vmid->ptb_assigned_to_vmid, 0, sizeof(core_vmid->ptb_assigned_to_vmid[0]) * MAX_VMID);
    130 }
    131 
    132 struct mod_vmid *mod_vmid_create(
    133 		struct dc *dc,
    134 		unsigned int num_vmid,
    135 		struct dc_virtual_addr_space_config *va_config)
    136 {
    137 	struct core_vmid *core_vmid;
    138 
    139 	if (num_vmid <= 1)
    140 		goto fail_no_vm_ctx;
    141 
    142 	if (dc == NULL)
    143 		goto fail_dc_null;
    144 
    145 	core_vmid = kzalloc(sizeof(struct core_vmid), GFP_KERNEL);
    146 
    147 	if (core_vmid == NULL)
    148 		goto fail_alloc_context;
    149 
    150 	core_vmid->dc = dc;
    151 	core_vmid->num_vmid = num_vmid;
    152 	core_vmid->num_vmids_available = num_vmid - 1;
    153 	core_vmid->base_config = *va_config;
    154 
    155 	memset(core_vmid->ptb_assigned_to_vmid, 0, sizeof(core_vmid->ptb_assigned_to_vmid[0]) * MAX_VMID);
    156 
    157 	return &core_vmid->public;
    158 
    159 fail_no_vm_ctx:
    160 fail_alloc_context:
    161 fail_dc_null:
    162 	return NULL;
    163 }
    164 
    165 void mod_vmid_destroy(struct mod_vmid *mod_vmid)
    166 {
    167 	if (mod_vmid != NULL) {
    168 		struct core_vmid *core_vmid = MOD_VMID_TO_CORE(mod_vmid);
    169 
    170 		kfree(core_vmid);
    171 	}
    172 }
    173