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/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
  20 #include <asm/cputable.h>
  21 #include <asm/kvm_ppc.h>
  22 #include <asm/kvm_book3s.h>
  23
  24 #include "book3s_hv_cma.h"
  25 /*
  26  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  27  * should be power of 2.
  28  */
  29 #define HPT_ALIGN_PAGES         ((1 << 18) >> PAGE_SHIFT) /* 256k */
  30 /*
  31  * By default we reserve 5% of memory for hash pagetable allocation.
  32  */
  33 static unsigned long kvm_cma_resv_ratio = 5;
  34 /*
  35  * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
  36  * Each RMA has to be physically contiguous and of a size that the
  37  * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
  38  * and other larger sizes.  Since we are unlikely to be allocate that
  39  * much physically contiguous memory after the system is up and running,
  40  * we preallocate a set of RMAs in early boot using CMA.
  41  * should be power of 2.
  42  */
  43 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;  /* 128MB */
  44 EXPORT_SYMBOL_GPL(kvm_rma_pages);
  45
  46 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
  47    Assumes POWER7 or PPC970. */
  48 static inline int lpcr_rmls(unsigned long rma_size)
  49 {
  50         switch (rma_size) {
  51         case 32ul << 20:        /* 32 MB */
  52                 if (cpu_has_feature(CPU_FTR_ARCH_206))
  53                         return 8;       /* only supported on POWER7 */
  54                 return -1;
  55         case 64ul << 20:        /* 64 MB */
  56                 return 3;
  57         case 128ul << 20:       /* 128 MB */
  58                 return 7;
  59         case 256ul << 20:       /* 256 MB */
  60                 return 4;
  61         case 1ul << 30:         /* 1 GB */
  62                 return 2;
  63         case 16ul << 30:        /* 16 GB */
  64                 return 1;
  65         case 256ul << 30:       /* 256 GB */
  66                 return 0;
  67         default:
  68                 return -1;
  69         }
  70 }
  71
  72 static int __init early_parse_rma_size(char *p)
  73 {
  74         unsigned long kvm_rma_size;
  75
  76         pr_debug("%s(%s)\n", __func__, p);
  77         if (!p)
  78                 return -EINVAL;
  79         kvm_rma_size = memparse(p, &p);
  80         /*
  81          * Check that the requested size is one supported in hardware
  82          */
  83         if (lpcr_rmls(kvm_rma_size) < 0) {
  84                 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
  85                 return -EINVAL;
  86         }
  87         kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
  88         return 0;
  89 }
  90 early_param("kvm_rma_size", early_parse_rma_size);
  91
  92 struct kvm_rma_info *kvm_alloc_rma()
  93 {
  94         struct page *page;
  95         struct kvm_rma_info *ri;
  96
  97         ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
  98         if (!ri)
  99                 return NULL;
 100         page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
 101         if (!page)
 102                 goto err_out;
 103         atomic_set(&ri->use_count, 1);
 104         ri->base_pfn = page_to_pfn(page);
 105         return ri;
 106 err_out:
 107         kfree(ri);
 108         return NULL;
 109 }
 110 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 111
 112 void kvm_release_rma(struct kvm_rma_info *ri)
 113 {
 114         if (atomic_dec_and_test(&ri->use_count)) {
 115                 kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
 116                 kfree(ri);
 117         }
 118 }
 119 EXPORT_SYMBOL_GPL(kvm_release_rma);
 120
 121 static int __init early_parse_kvm_cma_resv(char *p)
 122 {
 123         pr_debug("%s(%s)\n", __func__, p);
 124         if (!p)
 125                 return -EINVAL;
 126         return kstrtoul(p, 0, &kvm_cma_resv_ratio);
 127 }
 128 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
 129
 130 struct page *kvm_alloc_hpt(unsigned long nr_pages)
 131 {
 132         unsigned long align_pages = HPT_ALIGN_PAGES;
 133
 134         /* Old CPUs require HPT aligned on a multiple of its size */
 135         if (!cpu_has_feature(CPU_FTR_ARCH_206))
 136                 align_pages = nr_pages;
 137         return kvm_alloc_cma(nr_pages, align_pages);
 138 }
 139 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 140
 141 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 142 {
 143         kvm_release_cma(page, nr_pages);
 144 }
 145 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 146
 147 /**
 148  * kvm_cma_reserve() - reserve area for kvm hash pagetable
 149  *
 150  * This function reserves memory from early allocator. It should be
 151  * called by arch specific code once the early allocator (memblock or bootmem)
 152  * has been activated and all other subsystems have already allocated/reserved
 153  * memory.
 154  */
 155 void __init kvm_cma_reserve(void)
 156 {
 157         unsigned long align_size;
 158         struct memblock_region *reg;
 159         phys_addr_t selected_size = 0;
 160         /*
 161          * We cannot use memblock_phys_mem_size() here, because
 162          * memblock_analyze() has not been called yet.
 163          */
 164         for_each_memblock(memory, reg)
 165                 selected_size += memblock_region_memory_end_pfn(reg) -
 166                                  memblock_region_memory_base_pfn(reg);
 167
 168         selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
 169         if (selected_size) {
 170                 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
 171                          (unsigned long)selected_size / SZ_1M);
 172                 /*
 173                  * Old CPUs require HPT aligned on a multiple of its size. So for them
 174                  * make the alignment as max size we could request.
 175                  */
 176                 if (!cpu_has_feature(CPU_FTR_ARCH_206))
 177                         align_size = __rounddown_pow_of_two(selected_size);
 178                 else
 179                         align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 180
 181                 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
 182                 kvm_cma_declare_contiguous(selected_size, align_size);
 183         }
 184 }
 185
 186 /*
 187  * When running HV mode KVM we need to block certain operations while KVM VMs
 188  * exist in the system. We use a counter of VMs to track this.
 189  *
 190  * One of the operations we need to block is onlining of secondaries, so we
 191  * protect hv_vm_count with get/put_online_cpus().
 192  */
 193 static atomic_t hv_vm_count;
 194
 195 void kvm_hv_vm_activated(void)
 196 {
 197         get_online_cpus();
 198         atomic_inc(&hv_vm_count);
 199         put_online_cpus();
 200 }
 201 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
 202
 203 void kvm_hv_vm_deactivated(void)
 204 {
 205         get_online_cpus();
 206         atomic_dec(&hv_vm_count);
 207         put_online_cpus();
 208 }
 209 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
 210
 211 bool kvm_hv_mode_active(void)
 212 {
 213         return atomic_read(&hv_vm_count) != 0;
 214 }