1 /*
2  * Copyright 2018 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: AMD
23  *
24  */
25 
26 #include "vm_helper.h"
27 
28 static void mark_vmid_used(struct vm_helper *vm_helper, unsigned int pos, uint8_t hubp_idx)
29 {
30 	struct vmid_usage vmids = vm_helper->hubp_vmid_usage[hubp_idx];
31 
32 	vmids.vmid_usage[0] = vmids.vmid_usage[1];
33 	vmids.vmid_usage[1] = 1 << pos;
34 }
35 
36 static void add_ptb_to_table(struct vm_helper *vm_helper, unsigned int vmid, uint64_t ptb)
37 {
38 	vm_helper->ptb_assigned_to_vmid[vmid] = ptb;
39 	vm_helper->num_vmids_available--;
40 }
41 
42 static void clear_entry_from_vmid_table(struct vm_helper *vm_helper, unsigned int vmid)
43 {
44 	vm_helper->ptb_assigned_to_vmid[vmid] = 0;
45 	vm_helper->num_vmids_available++;
46 }
47 
48 static void evict_vmids(struct vm_helper *vm_helper)
49 {
50 	int i;
51 	uint16_t ord = 0;
52 
53 	for (i = 0; i < vm_helper->num_vmid; i++)
54 		ord |= vm_helper->hubp_vmid_usage[i].vmid_usage[0] | vm_helper->hubp_vmid_usage[i].vmid_usage[1];
55 
56 	// At this point any positions with value 0 are unused vmids, evict them
57 	for (i = 1; i < vm_helper->num_vmid; i++) {
58 		if (ord & (1u << i))
59 			clear_entry_from_vmid_table(vm_helper, i);
60 	}
61 }
62 
63 // Return value of -1 indicates vmid table unitialized or ptb dne in the table
64 static int get_existing_vmid_for_ptb(struct vm_helper *vm_helper, uint64_t ptb)
65 {
66 	int i;
67 
68 	for (i = 0; i < vm_helper->num_vmid; i++) {
69 		if (vm_helper->ptb_assigned_to_vmid[i] == ptb)
70 			return i;
71 	}
72 
73 	return -1;
74 }
75 
76 // Expected to be called only when there's an available vmid
77 static int get_next_available_vmid(struct vm_helper *vm_helper)
78 {
79 	int i;
80 
81 	for (i = 1; i < vm_helper->num_vmid; i++) {
82 		if (vm_helper->ptb_assigned_to_vmid[i] == 0)
83 			return i;
84 	}
85 
86 	return -1;
87 }
88 
89 uint8_t get_vmid_for_ptb(struct vm_helper *vm_helper, int64_t ptb, uint8_t hubp_idx)
90 {
91 	unsigned int vmid = 0;
92 	int vmid_exists = -1;
93 
94 	// Physical address gets vmid 0
95 	if (ptb == 0)
96 		return 0;
97 
98 	vmid_exists = get_existing_vmid_for_ptb(vm_helper, ptb);
99 
100 	if (vmid_exists != -1) {
101 		mark_vmid_used(vm_helper, vmid_exists, hubp_idx);
102 		vmid = vmid_exists;
103 	} else {
104 		if (vm_helper->num_vmids_available == 0)
105 			evict_vmids(vm_helper);
106 
107 		vmid = get_next_available_vmid(vm_helper);
108 		mark_vmid_used(vm_helper, vmid, hubp_idx);
109 		add_ptb_to_table(vm_helper, vmid, ptb);
110 	}
111 
112 	return vmid;
113 }
114 
115 void init_vm_helper(struct vm_helper *vm_helper, unsigned int num_vmid, unsigned int num_hubp)
116 {
117 	vm_helper->num_vmid = num_vmid;
118 	vm_helper->num_hubp = num_hubp;
119 	vm_helper->num_vmids_available = num_vmid - 1;
120 
121 	memset(vm_helper->hubp_vmid_usage, 0, sizeof(vm_helper->hubp_vmid_usage[0]) * MAX_HUBP);
122 	memset(vm_helper->ptb_assigned_to_vmid, 0, sizeof(vm_helper->ptb_assigned_to_vmid[0]) * MAX_VMID);
123 }
124