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 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 }