xref: /linux/arch/powerpc/kvm/book3s_hv_builtin.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License, version 2, as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/kvm_host.h>
10 #include <linux/preempt.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/spinlock.h>
14 #include <linux/bootmem.h>
15 #include <linux/init.h>
16 
17 #include <asm/cputable.h>
18 #include <asm/kvm_ppc.h>
19 #include <asm/kvm_book3s.h>
20 
21 #define KVM_LINEAR_RMA		0
22 #define KVM_LINEAR_HPT		1
23 
24 static void __init kvm_linear_init_one(ulong size, int count, int type);
25 static struct kvmppc_linear_info *kvm_alloc_linear(int type);
26 static void kvm_release_linear(struct kvmppc_linear_info *ri);
27 
28 int kvm_hpt_order = KVM_DEFAULT_HPT_ORDER;
29 EXPORT_SYMBOL_GPL(kvm_hpt_order);
30 
31 /*************** RMA *************/
32 
33 /*
34  * This maintains a list of RMAs (real mode areas) for KVM guests to use.
35  * Each RMA has to be physically contiguous and of a size that the
36  * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
37  * and other larger sizes.  Since we are unlikely to be allocate that
38  * much physically contiguous memory after the system is up and running,
39  * we preallocate a set of RMAs in early boot for KVM to use.
40  */
41 static unsigned long kvm_rma_size = 64 << 20;	/* 64MB */
42 static unsigned long kvm_rma_count;
43 
44 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
45    Assumes POWER7 or PPC970. */
46 static inline int lpcr_rmls(unsigned long rma_size)
47 {
48 	switch (rma_size) {
49 	case 32ul << 20:	/* 32 MB */
50 		if (cpu_has_feature(CPU_FTR_ARCH_206))
51 			return 8;	/* only supported on POWER7 */
52 		return -1;
53 	case 64ul << 20:	/* 64 MB */
54 		return 3;
55 	case 128ul << 20:	/* 128 MB */
56 		return 7;
57 	case 256ul << 20:	/* 256 MB */
58 		return 4;
59 	case 1ul << 30:		/* 1 GB */
60 		return 2;
61 	case 16ul << 30:	/* 16 GB */
62 		return 1;
63 	case 256ul << 30:	/* 256 GB */
64 		return 0;
65 	default:
66 		return -1;
67 	}
68 }
69 
70 static int __init early_parse_rma_size(char *p)
71 {
72 	if (!p)
73 		return 1;
74 
75 	kvm_rma_size = memparse(p, &p);
76 
77 	return 0;
78 }
79 early_param("kvm_rma_size", early_parse_rma_size);
80 
81 static int __init early_parse_rma_count(char *p)
82 {
83 	if (!p)
84 		return 1;
85 
86 	kvm_rma_count = simple_strtoul(p, NULL, 0);
87 
88 	return 0;
89 }
90 early_param("kvm_rma_count", early_parse_rma_count);
91 
92 struct kvmppc_linear_info *kvm_alloc_rma(void)
93 {
94 	return kvm_alloc_linear(KVM_LINEAR_RMA);
95 }
96 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
97 
98 void kvm_release_rma(struct kvmppc_linear_info *ri)
99 {
100 	kvm_release_linear(ri);
101 }
102 EXPORT_SYMBOL_GPL(kvm_release_rma);
103 
104 /*************** HPT *************/
105 
106 /*
107  * This maintains a list of big linear HPT tables that contain the GVA->HPA
108  * memory mappings. If we don't reserve those early on, we might not be able
109  * to get a big (usually 16MB) linear memory region from the kernel anymore.
110  */
111 
112 static unsigned long kvm_hpt_count;
113 
114 static int __init early_parse_hpt_count(char *p)
115 {
116 	if (!p)
117 		return 1;
118 
119 	kvm_hpt_count = simple_strtoul(p, NULL, 0);
120 
121 	return 0;
122 }
123 early_param("kvm_hpt_count", early_parse_hpt_count);
124 
125 struct kvmppc_linear_info *kvm_alloc_hpt(void)
126 {
127 	return kvm_alloc_linear(KVM_LINEAR_HPT);
128 }
129 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
130 
131 void kvm_release_hpt(struct kvmppc_linear_info *li)
132 {
133 	kvm_release_linear(li);
134 }
135 EXPORT_SYMBOL_GPL(kvm_release_hpt);
136 
137 /*************** generic *************/
138 
139 static LIST_HEAD(free_linears);
140 static DEFINE_SPINLOCK(linear_lock);
141 
142 static void __init kvm_linear_init_one(ulong size, int count, int type)
143 {
144 	unsigned long i;
145 	unsigned long j, npages;
146 	void *linear;
147 	struct page *pg;
148 	const char *typestr;
149 	struct kvmppc_linear_info *linear_info;
150 
151 	if (!count)
152 		return;
153 
154 	typestr = (type == KVM_LINEAR_RMA) ? "RMA" : "HPT";
155 
156 	npages = size >> PAGE_SHIFT;
157 	linear_info = alloc_bootmem(count * sizeof(struct kvmppc_linear_info));
158 	for (i = 0; i < count; ++i) {
159 		linear = alloc_bootmem_align(size, size);
160 		pr_debug("Allocated KVM %s at %p (%ld MB)\n", typestr, linear,
161 			 size >> 20);
162 		linear_info[i].base_virt = linear;
163 		linear_info[i].base_pfn = __pa(linear) >> PAGE_SHIFT;
164 		linear_info[i].npages = npages;
165 		linear_info[i].type = type;
166 		list_add_tail(&linear_info[i].list, &free_linears);
167 		atomic_set(&linear_info[i].use_count, 0);
168 
169 		pg = pfn_to_page(linear_info[i].base_pfn);
170 		for (j = 0; j < npages; ++j) {
171 			atomic_inc(&pg->_count);
172 			++pg;
173 		}
174 	}
175 }
176 
177 static struct kvmppc_linear_info *kvm_alloc_linear(int type)
178 {
179 	struct kvmppc_linear_info *ri, *ret;
180 
181 	ret = NULL;
182 	spin_lock(&linear_lock);
183 	list_for_each_entry(ri, &free_linears, list) {
184 		if (ri->type != type)
185 			continue;
186 
187 		list_del(&ri->list);
188 		atomic_inc(&ri->use_count);
189 		memset(ri->base_virt, 0, ri->npages << PAGE_SHIFT);
190 		ret = ri;
191 		break;
192 	}
193 	spin_unlock(&linear_lock);
194 	return ret;
195 }
196 
197 static void kvm_release_linear(struct kvmppc_linear_info *ri)
198 {
199 	if (atomic_dec_and_test(&ri->use_count)) {
200 		spin_lock(&linear_lock);
201 		list_add_tail(&ri->list, &free_linears);
202 		spin_unlock(&linear_lock);
203 
204 	}
205 }
206 
207 /*
208  * Called at boot time while the bootmem allocator is active,
209  * to allocate contiguous physical memory for the hash page
210  * tables for guests.
211  */
212 void __init kvm_linear_init(void)
213 {
214 	/* HPT */
215 	kvm_linear_init_one(1 << kvm_hpt_order, kvm_hpt_count, KVM_LINEAR_HPT);
216 
217 	/* RMA */
218 	/* Only do this on PPC970 in HV mode */
219 	if (!cpu_has_feature(CPU_FTR_HVMODE) ||
220 	    !cpu_has_feature(CPU_FTR_ARCH_201))
221 		return;
222 
223 	if (!kvm_rma_size || !kvm_rma_count)
224 		return;
225 
226 	/* Check that the requested size is one supported in hardware */
227 	if (lpcr_rmls(kvm_rma_size) < 0) {
228 		pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
229 		return;
230 	}
231 
232 	kvm_linear_init_one(kvm_rma_size, kvm_rma_count, KVM_LINEAR_RMA);
233 }
234