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/sched.h> 12 #include <linux/spinlock.h> 13 #include <linux/bootmem.h> 14 #include <linux/init.h> 15 16 #include <asm/cputable.h> 17 #include <asm/kvm_ppc.h> 18 #include <asm/kvm_book3s.h> 19 20 /* 21 * This maintains a list of RMAs (real mode areas) for KVM guests to use. 22 * Each RMA has to be physically contiguous and of a size that the 23 * hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB, 24 * and other larger sizes. Since we are unlikely to be allocate that 25 * much physically contiguous memory after the system is up and running, 26 * we preallocate a set of RMAs in early boot for KVM to use. 27 */ 28 static unsigned long kvm_rma_size = 64 << 20; /* 64MB */ 29 static unsigned long kvm_rma_count; 30 31 static int __init early_parse_rma_size(char *p) 32 { 33 if (!p) 34 return 1; 35 36 kvm_rma_size = memparse(p, &p); 37 38 return 0; 39 } 40 early_param("kvm_rma_size", early_parse_rma_size); 41 42 static int __init early_parse_rma_count(char *p) 43 { 44 if (!p) 45 return 1; 46 47 kvm_rma_count = simple_strtoul(p, NULL, 0); 48 49 return 0; 50 } 51 early_param("kvm_rma_count", early_parse_rma_count); 52 53 static struct kvmppc_rma_info *rma_info; 54 static LIST_HEAD(free_rmas); 55 static DEFINE_SPINLOCK(rma_lock); 56 57 /* Work out RMLS (real mode limit selector) field value for a given RMA size. 58 Assumes POWER7. */ 59 static inline int lpcr_rmls(unsigned long rma_size) 60 { 61 switch (rma_size) { 62 case 32ul << 20: /* 32 MB */ 63 return 8; 64 case 64ul << 20: /* 64 MB */ 65 return 3; 66 case 128ul << 20: /* 128 MB */ 67 return 7; 68 case 256ul << 20: /* 256 MB */ 69 return 4; 70 case 1ul << 30: /* 1 GB */ 71 return 2; 72 case 16ul << 30: /* 16 GB */ 73 return 1; 74 case 256ul << 30: /* 256 GB */ 75 return 0; 76 default: 77 return -1; 78 } 79 } 80 81 /* 82 * Called at boot time while the bootmem allocator is active, 83 * to allocate contiguous physical memory for the real memory 84 * areas for guests. 85 */ 86 void kvm_rma_init(void) 87 { 88 unsigned long i; 89 unsigned long j, npages; 90 void *rma; 91 struct page *pg; 92 93 /* Only do this in HV mode */ 94 if (!cpu_has_feature(CPU_FTR_HVMODE)) 95 return; 96 97 if (!kvm_rma_size || !kvm_rma_count) 98 return; 99 100 /* Check that the requested size is one supported in hardware */ 101 if (lpcr_rmls(kvm_rma_size) < 0) { 102 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size); 103 return; 104 } 105 106 npages = kvm_rma_size >> PAGE_SHIFT; 107 rma_info = alloc_bootmem(kvm_rma_count * sizeof(struct kvmppc_rma_info)); 108 for (i = 0; i < kvm_rma_count; ++i) { 109 rma = alloc_bootmem_align(kvm_rma_size, kvm_rma_size); 110 pr_info("Allocated KVM RMA at %p (%ld MB)\n", rma, 111 kvm_rma_size >> 20); 112 rma_info[i].base_virt = rma; 113 rma_info[i].base_pfn = __pa(rma) >> PAGE_SHIFT; 114 rma_info[i].npages = npages; 115 list_add_tail(&rma_info[i].list, &free_rmas); 116 atomic_set(&rma_info[i].use_count, 0); 117 118 pg = pfn_to_page(rma_info[i].base_pfn); 119 for (j = 0; j < npages; ++j) { 120 atomic_inc(&pg->_count); 121 ++pg; 122 } 123 } 124 } 125 126 struct kvmppc_rma_info *kvm_alloc_rma(void) 127 { 128 struct kvmppc_rma_info *ri; 129 130 ri = NULL; 131 spin_lock(&rma_lock); 132 if (!list_empty(&free_rmas)) { 133 ri = list_first_entry(&free_rmas, struct kvmppc_rma_info, list); 134 list_del(&ri->list); 135 atomic_inc(&ri->use_count); 136 } 137 spin_unlock(&rma_lock); 138 return ri; 139 } 140 EXPORT_SYMBOL_GPL(kvm_alloc_rma); 141 142 void kvm_release_rma(struct kvmppc_rma_info *ri) 143 { 144 if (atomic_dec_and_test(&ri->use_count)) { 145 spin_lock(&rma_lock); 146 list_add_tail(&ri->list, &free_rmas); 147 spin_unlock(&rma_lock); 148 149 } 150 } 151 EXPORT_SYMBOL_GPL(kvm_release_rma); 152 153