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 #include <linux/memblock.h>
  17 #include <linux/sizes.h>
  18
  19 #include <asm/cputable.h>
  20 #include <asm/kvm_ppc.h>
  21 #include <asm/kvm_book3s.h>
  22
  23 #include "book3s_hv_cma.h"
  24 /*
  25  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  26  * should be power of 2.
  27  */
  28 #define HPT_ALIGN_PAGES         ((1 << 18) >> PAGE_SHIFT) /* 256k */
  29 /*
  30  * By default we reserve 5% of memory for hash pagetable allocation.
  31  */
  32 static unsigned long kvm_cma_resv_ratio = 5;
  33 /*
  34  * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
  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 using CMA.
  40  * should be power of 2.
  41  */
  42 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;  /* 128MB */
  43 EXPORT_SYMBOL_GPL(kvm_rma_pages);
  44
  45 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
  46    Assumes POWER7 or PPC970. */
  47 static inline int lpcr_rmls(unsigned long rma_size)
  48 {
  49         switch (rma_size) {
  50         case 32ul << 20:        /* 32 MB */
  51                 if (cpu_has_feature(CPU_FTR_ARCH_206))
  52                         return 8;       /* only supported on POWER7 */
  53                 return -1;
  54         case 64ul << 20:        /* 64 MB */
  55                 return 3;
  56         case 128ul << 20:       /* 128 MB */
  57                 return 7;
  58         case 256ul << 20:       /* 256 MB */
  59                 return 4;
  60         case 1ul << 30:         /* 1 GB */
  61                 return 2;
  62         case 16ul << 30:        /* 16 GB */
  63                 return 1;
  64         case 256ul << 30:       /* 256 GB */
  65                 return 0;
  66         default:
  67                 return -1;
  68         }
  69 }
  70
  71 static int __init early_parse_rma_size(char *p)
  72 {
  73         unsigned long kvm_rma_size;
  74
  75         pr_debug("%s(%s)\n", __func__, p);
  76         if (!p)
  77                 return -EINVAL;
  78         kvm_rma_size = memparse(p, &p);
  79         /*
  80          * Check that the requested size is one supported in hardware
  81          */
  82         if (lpcr_rmls(kvm_rma_size) < 0) {
  83                 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
  84                 return -EINVAL;
  85         }
  86         kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
  87         return 0;
  88 }
  89 early_param("kvm_rma_size", early_parse_rma_size);
  90
  91 struct kvm_rma_info *kvm_alloc_rma()
  92 {
  93         struct page *page;
  94         struct kvm_rma_info *ri;
  95
  96         ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
  97         if (!ri)
  98                 return NULL;
  99         page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
 100         if (!page)
 101                 goto err_out;
 102         atomic_set(&ri->use_count, 1);
 103         ri->base_pfn = page_to_pfn(page);
 104         return ri;
 105 err_out:
 106         kfree(ri);
 107         return NULL;
 108 }
 109 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 110
 111 void kvm_release_rma(struct kvm_rma_info *ri)
 112 {
 113         if (atomic_dec_and_test(&ri->use_count)) {
 114                 kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
 115                 kfree(ri);
 116         }
 117 }
 118 EXPORT_SYMBOL_GPL(kvm_release_rma);
 119
 120 static int __init early_parse_kvm_cma_resv(char *p)
 121 {
 122         pr_debug("%s(%s)\n", __func__, p);
 123         if (!p)
 124                 return -EINVAL;
 125         return kstrtoul(p, 0, &kvm_cma_resv_ratio);
 126 }
 127 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
 128
 129 struct page *kvm_alloc_hpt(unsigned long nr_pages)
 130 {
 131         unsigned long align_pages = HPT_ALIGN_PAGES;
 132
 133         /* Old CPUs require HPT aligned on a multiple of its size */
 134         if (!cpu_has_feature(CPU_FTR_ARCH_206))
 135                 align_pages = nr_pages;
 136         return kvm_alloc_cma(nr_pages, align_pages);
 137 }
 138 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 139
 140 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 141 {
 142         kvm_release_cma(page, nr_pages);
 143 }
 144 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 145
 146 /**
 147  * kvm_cma_reserve() - reserve area for kvm hash pagetable
 148  *
 149  * This function reserves memory from early allocator. It should be
 150  * called by arch specific code once the early allocator (memblock or bootmem)
 151  * has been activated and all other subsystems have already allocated/reserved
 152  * memory.
 153  */
 154 void __init kvm_cma_reserve(void)
 155 {
 156         unsigned long align_size;
 157         struct memblock_region *reg;
 158         phys_addr_t selected_size = 0;
 159         /*
 160          * We cannot use memblock_phys_mem_size() here, because
 161          * memblock_analyze() has not been called yet.
 162          */
 163         for_each_memblock(memory, reg)
 164                 selected_size += memblock_region_memory_end_pfn(reg) -
 165                                  memblock_region_memory_base_pfn(reg);
 166
 167         selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
 168         if (selected_size) {
 169                 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
 170                          (unsigned long)selected_size / SZ_1M);
 171                 /*
 172                  * Old CPUs require HPT aligned on a multiple of its size. So for them
 173                  * make the alignment as max size we could request.
 174                  */
 175                 if (!cpu_has_feature(CPU_FTR_ARCH_206))
 176                         align_size = __rounddown_pow_of_two(selected_size);
 177                 else
 178                         align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 179
 180                 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
 181                 kvm_cma_declare_contiguous(selected_size, align_size);
 182         }
 183 }