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 } 215