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/init.h> 16 #include <linux/memblock.h> 17 #include <linux/sizes.h> 18 #include <linux/cma.h> 19 20 #include <asm/cputable.h> 21 #include <asm/kvm_ppc.h> 22 #include <asm/kvm_book3s.h> 23 24 #define KVM_CMA_CHUNK_ORDER 18 25 26 /* 27 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206) 28 * should be power of 2. 29 */ 30 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */ 31 /* 32 * By default we reserve 5% of memory for hash pagetable allocation. 33 */ 34 static unsigned long kvm_cma_resv_ratio = 5; 35 /* 36 * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area. 37 * Each RMA has to be physically contiguous and of a size that the 38 * hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB, 39 * and other larger sizes. Since we are unlikely to be allocate that 40 * much physically contiguous memory after the system is up and running, 41 * we preallocate a set of RMAs in early boot using CMA. 42 * should be power of 2. 43 */ 44 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */ 45 EXPORT_SYMBOL_GPL(kvm_rma_pages); 46 47 static struct cma *kvm_cma; 48 49 /* Work out RMLS (real mode limit selector) field value for a given RMA size. 50 Assumes POWER7 or PPC970. */ 51 static inline int lpcr_rmls(unsigned long rma_size) 52 { 53 switch (rma_size) { 54 case 32ul << 20: /* 32 MB */ 55 if (cpu_has_feature(CPU_FTR_ARCH_206)) 56 return 8; /* only supported on POWER7 */ 57 return -1; 58 case 64ul << 20: /* 64 MB */ 59 return 3; 60 case 128ul << 20: /* 128 MB */ 61 return 7; 62 case 256ul << 20: /* 256 MB */ 63 return 4; 64 case 1ul << 30: /* 1 GB */ 65 return 2; 66 case 16ul << 30: /* 16 GB */ 67 return 1; 68 case 256ul << 30: /* 256 GB */ 69 return 0; 70 default: 71 return -1; 72 } 73 } 74 75 static int __init early_parse_rma_size(char *p) 76 { 77 unsigned long kvm_rma_size; 78 79 pr_debug("%s(%s)\n", __func__, p); 80 if (!p) 81 return -EINVAL; 82 kvm_rma_size = memparse(p, &p); 83 /* 84 * Check that the requested size is one supported in hardware 85 */ 86 if (lpcr_rmls(kvm_rma_size) < 0) { 87 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size); 88 return -EINVAL; 89 } 90 kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT; 91 return 0; 92 } 93 early_param("kvm_rma_size", early_parse_rma_size); 94 95 struct kvm_rma_info *kvm_alloc_rma() 96 { 97 struct page *page; 98 struct kvm_rma_info *ri; 99 100 ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL); 101 if (!ri) 102 return NULL; 103 page = cma_alloc(kvm_cma, kvm_rma_pages, order_base_2(kvm_rma_pages)); 104 if (!page) 105 goto err_out; 106 atomic_set(&ri->use_count, 1); 107 ri->base_pfn = page_to_pfn(page); 108 return ri; 109 err_out: 110 kfree(ri); 111 return NULL; 112 } 113 EXPORT_SYMBOL_GPL(kvm_alloc_rma); 114 115 void kvm_release_rma(struct kvm_rma_info *ri) 116 { 117 if (atomic_dec_and_test(&ri->use_count)) { 118 cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages); 119 kfree(ri); 120 } 121 } 122 EXPORT_SYMBOL_GPL(kvm_release_rma); 123 124 static int __init early_parse_kvm_cma_resv(char *p) 125 { 126 pr_debug("%s(%s)\n", __func__, p); 127 if (!p) 128 return -EINVAL; 129 return kstrtoul(p, 0, &kvm_cma_resv_ratio); 130 } 131 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv); 132 133 struct page *kvm_alloc_hpt(unsigned long nr_pages) 134 { 135 unsigned long align_pages = HPT_ALIGN_PAGES; 136 137 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); 138 139 /* Old CPUs require HPT aligned on a multiple of its size */ 140 if (!cpu_has_feature(CPU_FTR_ARCH_206)) 141 align_pages = nr_pages; 142 return cma_alloc(kvm_cma, nr_pages, order_base_2(align_pages)); 143 } 144 EXPORT_SYMBOL_GPL(kvm_alloc_hpt); 145 146 void kvm_release_hpt(struct page *page, unsigned long nr_pages) 147 { 148 cma_release(kvm_cma, page, nr_pages); 149 } 150 EXPORT_SYMBOL_GPL(kvm_release_hpt); 151 152 /** 153 * kvm_cma_reserve() - reserve area for kvm hash pagetable 154 * 155 * This function reserves memory from early allocator. It should be 156 * called by arch specific code once the memblock allocator 157 * has been activated and all other subsystems have already allocated/reserved 158 * memory. 159 */ 160 void __init kvm_cma_reserve(void) 161 { 162 unsigned long align_size; 163 struct memblock_region *reg; 164 phys_addr_t selected_size = 0; 165 166 /* 167 * We need CMA reservation only when we are in HV mode 168 */ 169 if (!cpu_has_feature(CPU_FTR_HVMODE)) 170 return; 171 /* 172 * We cannot use memblock_phys_mem_size() here, because 173 * memblock_analyze() has not been called yet. 174 */ 175 for_each_memblock(memory, reg) 176 selected_size += memblock_region_memory_end_pfn(reg) - 177 memblock_region_memory_base_pfn(reg); 178 179 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT; 180 if (selected_size) { 181 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 182 (unsigned long)selected_size / SZ_1M); 183 /* 184 * Old CPUs require HPT aligned on a multiple of its size. So for them 185 * make the alignment as max size we could request. 186 */ 187 if (!cpu_has_feature(CPU_FTR_ARCH_206)) 188 align_size = __rounddown_pow_of_two(selected_size); 189 else 190 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT; 191 192 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size); 193 cma_declare_contiguous(0, selected_size, 0, align_size, 194 KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma); 195 } 196 } 197 198 /* 199 * When running HV mode KVM we need to block certain operations while KVM VMs 200 * exist in the system. We use a counter of VMs to track this. 201 * 202 * One of the operations we need to block is onlining of secondaries, so we 203 * protect hv_vm_count with get/put_online_cpus(). 204 */ 205 static atomic_t hv_vm_count; 206 207 void kvm_hv_vm_activated(void) 208 { 209 get_online_cpus(); 210 atomic_inc(&hv_vm_count); 211 put_online_cpus(); 212 } 213 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated); 214 215 void kvm_hv_vm_deactivated(void) 216 { 217 get_online_cpus(); 218 atomic_dec(&hv_vm_count); 219 put_online_cpus(); 220 } 221 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated); 222 223 bool kvm_hv_mode_active(void) 224 { 225 return atomic_read(&hv_vm_count) != 0; 226 } 227 228 extern int hcall_real_table[], hcall_real_table_end[]; 229 230 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd) 231 { 232 cmd /= 4; 233 if (cmd < hcall_real_table_end - hcall_real_table && 234 hcall_real_table[cmd]) 235 return 1; 236 237 return 0; 238 } 239 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode); 240