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/cpu.h>
10 #include <linux/kvm_host.h>
11 #include <linux/preempt.h>
12 #include <linux/export.h>
13 #include <linux/sched.h>
14 #include <linux/spinlock.h>
15 #include <linux/bootmem.h>
16 #include <linux/init.h>
17 #include <linux/memblock.h>
18 #include <linux/sizes.h>
19 #include <linux/cma.h>
20
21 #include <asm/cputable.h>
22 #include <asm/kvm_ppc.h>
23 #include <asm/kvm_book3s.h>
24
25 #define KVM_CMA_CHUNK_ORDER 18
26
27 /*
28 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
29 * should be power of 2.
30 */
31 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
32 /*
33 * By default we reserve 5% of memory for hash pagetable allocation.
34 */
35 static unsigned long kvm_cma_resv_ratio = 5;
36 /*
37 * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
38 * Each RMA has to be physically contiguous and of a size that the
39 * hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB,
40 * and other larger sizes. Since we are unlikely to be allocate that
41 * much physically contiguous memory after the system is up and running,
42 * we preallocate a set of RMAs in early boot using CMA.
43 * should be power of 2.
44 */
45 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
46 EXPORT_SYMBOL_GPL(kvm_rma_pages);
47
48 static struct cma *kvm_cma;
49
50 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
51 Assumes POWER7 or PPC970. */
lpcr_rmls(unsigned long rma_size)52 static inline int lpcr_rmls(unsigned long rma_size)
53 {
54 switch (rma_size) {
55 case 32ul << 20: /* 32 MB */
56 if (cpu_has_feature(CPU_FTR_ARCH_206))
57 return 8; /* only supported on POWER7 */
58 return -1;
59 case 64ul << 20: /* 64 MB */
60 return 3;
61 case 128ul << 20: /* 128 MB */
62 return 7;
63 case 256ul << 20: /* 256 MB */
64 return 4;
65 case 1ul << 30: /* 1 GB */
66 return 2;
67 case 16ul << 30: /* 16 GB */
68 return 1;
69 case 256ul << 30: /* 256 GB */
70 return 0;
71 default:
72 return -1;
73 }
74 }
75
early_parse_rma_size(char * p)76 static int __init early_parse_rma_size(char *p)
77 {
78 unsigned long kvm_rma_size;
79
80 pr_debug("%s(%s)\n", __func__, p);
81 if (!p)
82 return -EINVAL;
83 kvm_rma_size = memparse(p, &p);
84 /*
85 * Check that the requested size is one supported in hardware
86 */
87 if (lpcr_rmls(kvm_rma_size) < 0) {
88 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
89 return -EINVAL;
90 }
91 kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
92 return 0;
93 }
94 early_param("kvm_rma_size", early_parse_rma_size);
95
kvm_alloc_rma()96 struct kvm_rma_info *kvm_alloc_rma()
97 {
98 struct page *page;
99 struct kvm_rma_info *ri;
100
101 ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
102 if (!ri)
103 return NULL;
104 page = cma_alloc(kvm_cma, kvm_rma_pages, order_base_2(kvm_rma_pages));
105 if (!page)
106 goto err_out;
107 atomic_set(&ri->use_count, 1);
108 ri->base_pfn = page_to_pfn(page);
109 return ri;
110 err_out:
111 kfree(ri);
112 return NULL;
113 }
114 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
115
kvm_release_rma(struct kvm_rma_info * ri)116 void kvm_release_rma(struct kvm_rma_info *ri)
117 {
118 if (atomic_dec_and_test(&ri->use_count)) {
119 cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
120 kfree(ri);
121 }
122 }
123 EXPORT_SYMBOL_GPL(kvm_release_rma);
124
early_parse_kvm_cma_resv(char * p)125 static int __init early_parse_kvm_cma_resv(char *p)
126 {
127 pr_debug("%s(%s)\n", __func__, p);
128 if (!p)
129 return -EINVAL;
130 return kstrtoul(p, 0, &kvm_cma_resv_ratio);
131 }
132 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
133
kvm_alloc_hpt(unsigned long nr_pages)134 struct page *kvm_alloc_hpt(unsigned long nr_pages)
135 {
136 unsigned long align_pages = HPT_ALIGN_PAGES;
137
138 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
139
140 /* Old CPUs require HPT aligned on a multiple of its size */
141 if (!cpu_has_feature(CPU_FTR_ARCH_206))
142 align_pages = nr_pages;
143 return cma_alloc(kvm_cma, nr_pages, order_base_2(align_pages));
144 }
145 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
146
kvm_release_hpt(struct page * page,unsigned long nr_pages)147 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
148 {
149 cma_release(kvm_cma, page, nr_pages);
150 }
151 EXPORT_SYMBOL_GPL(kvm_release_hpt);
152
153 /**
154 * kvm_cma_reserve() - reserve area for kvm hash pagetable
155 *
156 * This function reserves memory from early allocator. It should be
157 * called by arch specific code once the early allocator (memblock or bootmem)
158 * has been activated and all other subsystems have already allocated/reserved
159 * memory.
160 */
kvm_cma_reserve(void)161 void __init kvm_cma_reserve(void)
162 {
163 unsigned long align_size;
164 struct memblock_region *reg;
165 phys_addr_t selected_size = 0;
166
167 /*
168 * We need CMA reservation only when we are in HV mode
169 */
170 if (!cpu_has_feature(CPU_FTR_HVMODE))
171 return;
172 /*
173 * We cannot use memblock_phys_mem_size() here, because
174 * memblock_analyze() has not been called yet.
175 */
176 for_each_memblock(memory, reg)
177 selected_size += memblock_region_memory_end_pfn(reg) -
178 memblock_region_memory_base_pfn(reg);
179
180 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
181 if (selected_size) {
182 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
183 (unsigned long)selected_size / SZ_1M);
184 /*
185 * Old CPUs require HPT aligned on a multiple of its size. So for them
186 * make the alignment as max size we could request.
187 */
188 if (!cpu_has_feature(CPU_FTR_ARCH_206))
189 align_size = __rounddown_pow_of_two(selected_size);
190 else
191 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
192
193 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
194 cma_declare_contiguous(0, selected_size, 0, align_size,
195 KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
196 }
197 }
198
199 /*
200 * When running HV mode KVM we need to block certain operations while KVM VMs
201 * exist in the system. We use a counter of VMs to track this.
202 *
203 * One of the operations we need to block is onlining of secondaries, so we
204 * protect hv_vm_count with get/put_online_cpus().
205 */
206 static atomic_t hv_vm_count;
207
kvm_hv_vm_activated(void)208 void kvm_hv_vm_activated(void)
209 {
210 get_online_cpus();
211 atomic_inc(&hv_vm_count);
212 put_online_cpus();
213 }
214 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
215
kvm_hv_vm_deactivated(void)216 void kvm_hv_vm_deactivated(void)
217 {
218 get_online_cpus();
219 atomic_dec(&hv_vm_count);
220 put_online_cpus();
221 }
222 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
223
kvm_hv_mode_active(void)224 bool kvm_hv_mode_active(void)
225 {
226 return atomic_read(&hv_vm_count) != 0;
227 }
228
229 extern int hcall_real_table[], hcall_real_table_end[];
230
kvmppc_hcall_impl_hv_realmode(unsigned long cmd)231 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd)
232 {
233 cmd /= 4;
234 if (cmd < hcall_real_table_end - hcall_real_table &&
235 hcall_real_table[cmd])
236 return 1;
237
238 return 0;
239 }
240 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode);
241