arch/powerpc/kvm/book3s_hv_builtin.c

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