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 /*
  22  * This maintains a list of RMAs (real mode areas) for KVM guests to use.
  23  * Each RMA has to be physically contiguous and of a size that the
  24  * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
  25  * and other larger sizes.  Since we are unlikely to be allocate that
  26  * much physically contiguous memory after the system is up and running,
  27  * we preallocate a set of RMAs in early boot for KVM to use.
  28  */
  29 static unsigned long kvm_rma_size = 64 << 20;   /* 64MB */
  30 static unsigned long kvm_rma_count;
  31
  32 static int __init early_parse_rma_size(char *p)
  33 {
  34         if (!p)
  35                 return 1;
  36
  37         kvm_rma_size = memparse(p, &p);
  38
  39         return 0;
  40 }
  41 early_param("kvm_rma_size", early_parse_rma_size);
  42
  43 static int __init early_parse_rma_count(char *p)
  44 {
  45         if (!p)
  46                 return 1;
  47
  48         kvm_rma_count = simple_strtoul(p, NULL, 0);
  49
  50         return 0;
  51 }
  52 early_param("kvm_rma_count", early_parse_rma_count);
  53
  54 static struct kvmppc_rma_info *rma_info;
  55 static LIST_HEAD(free_rmas);
  56 static DEFINE_SPINLOCK(rma_lock);
  57
  58 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
  59    Assumes POWER7 or PPC970. */
  60 static inline int lpcr_rmls(unsigned long rma_size)
  61 {
  62         switch (rma_size) {
  63         case 32ul << 20:        /* 32 MB */
  64                 if (cpu_has_feature(CPU_FTR_ARCH_206))
  65                         return 8;       /* only supported on POWER7 */
  66                 return -1;
  67         case 64ul << 20:        /* 64 MB */
  68                 return 3;
  69         case 128ul << 20:       /* 128 MB */
  70                 return 7;
  71         case 256ul << 20:       /* 256 MB */
  72                 return 4;
  73         case 1ul << 30:         /* 1 GB */
  74                 return 2;
  75         case 16ul << 30:        /* 16 GB */
  76                 return 1;
  77         case 256ul << 30:       /* 256 GB */
  78                 return 0;
  79         default:
  80                 return -1;
  81         }
  82 }
  83
  84 /*
  85  * Called at boot time while the bootmem allocator is active,
  86  * to allocate contiguous physical memory for the real memory
  87  * areas for guests.
  88  */
  89 void __init kvm_rma_init(void)
  90 {
  91         unsigned long i;
  92         unsigned long j, npages;
  93         void *rma;
  94         struct page *pg;
  95
  96         /* Only do this on PPC970 in HV mode */
  97         if (!cpu_has_feature(CPU_FTR_HVMODE) ||
  98             !cpu_has_feature(CPU_FTR_ARCH_201))
  99                 return;
 100
 101         if (!kvm_rma_size || !kvm_rma_count)
 102                 return;
 103
 104         /* Check that the requested size is one supported in hardware */
 105         if (lpcr_rmls(kvm_rma_size) < 0) {
 106                 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
 107                 return;
 108         }
 109
 110         npages = kvm_rma_size >> PAGE_SHIFT;
 111         rma_info = alloc_bootmem(kvm_rma_count * sizeof(struct kvmppc_rma_info));
 112         for (i = 0; i < kvm_rma_count; ++i) {
 113                 rma = alloc_bootmem_align(kvm_rma_size, kvm_rma_size);
 114                 pr_info("Allocated KVM RMA at %p (%ld MB)\n", rma,
 115                         kvm_rma_size >> 20);
 116                 rma_info[i].base_virt = rma;
 117                 rma_info[i].base_pfn = __pa(rma) >> PAGE_SHIFT;
 118                 rma_info[i].npages = npages;
 119                 list_add_tail(&rma_info[i].list, &free_rmas);
 120                 atomic_set(&rma_info[i].use_count, 0);
 121
 122                 pg = pfn_to_page(rma_info[i].base_pfn);
 123                 for (j = 0; j < npages; ++j) {
 124                         atomic_inc(&pg->_count);
 125                         ++pg;
 126                 }
 127         }
 128 }
 129
 130 struct kvmppc_rma_info *kvm_alloc_rma(void)
 131 {
 132         struct kvmppc_rma_info *ri;
 133
 134         ri = NULL;
 135         spin_lock(&rma_lock);
 136         if (!list_empty(&free_rmas)) {
 137                 ri = list_first_entry(&free_rmas, struct kvmppc_rma_info, list);
 138                 list_del(&ri->list);
 139                 atomic_inc(&ri->use_count);
 140         }
 141         spin_unlock(&rma_lock);
 142         return ri;
 143 }
 144 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 145
 146 void kvm_release_rma(struct kvmppc_rma_info *ri)
 147 {
 148         if (atomic_dec_and_test(&ri->use_count)) {
 149                 spin_lock(&rma_lock);
 150                 list_add_tail(&ri->list, &free_rmas);
 151                 spin_unlock(&rma_lock);
 152
 153         }
 154 }
 155 EXPORT_SYMBOL_GPL(kvm_release_rma);
 156