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 #include <linux/cma.h> 20 21 #include <asm/cputable.h> 22 #include <asm/kvm_ppc.h> 23 #include <asm/kvm_book3s.h> 24 25 #define KVM_CMA_CHUNK_ORDER 18 26 27 /* 28 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206) 29 * should be power of 2. 30 */ 31 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */ 32 /* 33 * By default we reserve 5% of memory for hash pagetable allocation. 34 */ 35 static unsigned long kvm_cma_resv_ratio = 5; 36 /* 37 * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area. 38 * Each RMA has to be physically contiguous and of a size that the 39 * hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB, 40 * and other larger sizes. Since we are unlikely to be allocate that 41 * much physically contiguous memory after the system is up and running, 42 * we preallocate a set of RMAs in early boot using CMA. 43 * should be power of 2. 44 */ 45 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */ 46 EXPORT_SYMBOL_GPL(kvm_rma_pages); 47 48 static struct cma *kvm_cma; 49 50 /* Work out RMLS (real mode limit selector) field value for a given RMA size. 51 Assumes POWER7 or PPC970. */ 52 static inline int lpcr_rmls(unsigned long rma_size) 53 { 54 switch (rma_size) { 55 case 32ul << 20: /* 32 MB */ 56 if (cpu_has_feature(CPU_FTR_ARCH_206)) 57 return 8; /* only supported on POWER7 */ 58 return -1; 59 case 64ul << 20: /* 64 MB */ 60 return 3; 61 case 128ul << 20: /* 128 MB */ 62 return 7; 63 case 256ul << 20: /* 256 MB */ 64 return 4; 65 case 1ul << 30: /* 1 GB */ 66 return 2; 67 case 16ul << 30: /* 16 GB */ 68 return 1; 69 case 256ul << 30: /* 256 GB */ 70 return 0; 71 default: 72 return -1; 73 } 74 } 75 76 static int __init early_parse_rma_size(char *p) 77 { 78 unsigned long kvm_rma_size; 79 80 pr_debug("%s(%s)\n", __func__, p); 81 if (!p) 82 return -EINVAL; 83 kvm_rma_size = memparse(p, &p); 84 /* 85 * Check that the requested size is one supported in hardware 86 */ 87 if (lpcr_rmls(kvm_rma_size) < 0) { 88 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size); 89 return -EINVAL; 90 } 91 kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT; 92 return 0; 93 } 94 early_param("kvm_rma_size", early_parse_rma_size); 95 96 struct kvm_rma_info *kvm_alloc_rma() 97 { 98 struct page *page; 99 struct kvm_rma_info *ri; 100 101 ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL); 102 if (!ri) 103 return NULL; 104 page = cma_alloc(kvm_cma, kvm_rma_pages, order_base_2(kvm_rma_pages)); 105 if (!page) 106 goto err_out; 107 atomic_set(&ri->use_count, 1); 108 ri->base_pfn = page_to_pfn(page); 109 return ri; 110 err_out: 111 kfree(ri); 112 return NULL; 113 } 114 EXPORT_SYMBOL_GPL(kvm_alloc_rma); 115 116 void kvm_release_rma(struct kvm_rma_info *ri) 117 { 118 if (atomic_dec_and_test(&ri->use_count)) { 119 cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages); 120 kfree(ri); 121 } 122 } 123 EXPORT_SYMBOL_GPL(kvm_release_rma); 124 125 static int __init early_parse_kvm_cma_resv(char *p) 126 { 127 pr_debug("%s(%s)\n", __func__, p); 128 if (!p) 129 return -EINVAL; 130 return kstrtoul(p, 0, &kvm_cma_resv_ratio); 131 } 132 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv); 133 134 struct page *kvm_alloc_hpt(unsigned long nr_pages) 135 { 136 unsigned long align_pages = HPT_ALIGN_PAGES; 137 138 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); 139 140 /* Old CPUs require HPT aligned on a multiple of its size */ 141 if (!cpu_has_feature(CPU_FTR_ARCH_206)) 142 align_pages = nr_pages; 143 return cma_alloc(kvm_cma, nr_pages, order_base_2(align_pages)); 144 } 145 EXPORT_SYMBOL_GPL(kvm_alloc_hpt); 146 147 void kvm_release_hpt(struct page *page, unsigned long nr_pages) 148 { 149 cma_release(kvm_cma, page, nr_pages); 150 } 151 EXPORT_SYMBOL_GPL(kvm_release_hpt); 152 153 /** 154 * kvm_cma_reserve() - reserve area for kvm hash pagetable 155 * 156 * This function reserves memory from early allocator. It should be 157 * called by arch specific code once the early allocator (memblock or bootmem) 158 * has been activated and all other subsystems have already allocated/reserved 159 * memory. 160 */ 161 void __init kvm_cma_reserve(void) 162 { 163 unsigned long align_size; 164 struct memblock_region *reg; 165 phys_addr_t selected_size = 0; 166 167 /* 168 * We need CMA reservation only when we are in HV mode 169 */ 170 if (!cpu_has_feature(CPU_FTR_HVMODE)) 171 return; 172 /* 173 * We cannot use memblock_phys_mem_size() here, because 174 * memblock_analyze() has not been called yet. 175 */ 176 for_each_memblock(memory, reg) 177 selected_size += memblock_region_memory_end_pfn(reg) - 178 memblock_region_memory_base_pfn(reg); 179 180 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT; 181 if (selected_size) { 182 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 183 (unsigned long)selected_size / SZ_1M); 184 /* 185 * Old CPUs require HPT aligned on a multiple of its size. So for them 186 * make the alignment as max size we could request. 187 */ 188 if (!cpu_has_feature(CPU_FTR_ARCH_206)) 189 align_size = __rounddown_pow_of_two(selected_size); 190 else 191 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT; 192 193 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size); 194 cma_declare_contiguous(0, selected_size, 0, align_size, 195 KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma); 196 } 197 } 198 199 /* 200 * When running HV mode KVM we need to block certain operations while KVM VMs 201 * exist in the system. We use a counter of VMs to track this. 202 * 203 * One of the operations we need to block is onlining of secondaries, so we 204 * protect hv_vm_count with get/put_online_cpus(). 205 */ 206 static atomic_t hv_vm_count; 207 208 void kvm_hv_vm_activated(void) 209 { 210 get_online_cpus(); 211 atomic_inc(&hv_vm_count); 212 put_online_cpus(); 213 } 214 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated); 215 216 void kvm_hv_vm_deactivated(void) 217 { 218 get_online_cpus(); 219 atomic_dec(&hv_vm_count); 220 put_online_cpus(); 221 } 222 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated); 223 224 bool kvm_hv_mode_active(void) 225 { 226 return atomic_read(&hv_vm_count) != 0; 227 } 228 229 extern int hcall_real_table[], hcall_real_table_end[]; 230 231 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd) 232 { 233 cmd /= 4; 234 if (cmd < hcall_real_table_end - hcall_real_table && 235 hcall_real_table[cmd]) 236 return 1; 237 238 return 0; 239 } 240 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode); 241