2 * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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.
9 #include <linux/kvm_host.h>
10 #include <linux/preempt.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/spinlock.h>
14 #include <linux/bootmem.h>
15 #include <linux/init.h>
17 #include <asm/cputable.h>
18 #include <asm/kvm_ppc.h>
19 #include <asm/kvm_book3s.h>
22 * This maintains a list of RMAs (real mode areas) for KVM guests to use.
23 * Each RMA has to be physically contiguous and of a size that the
24 * hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB,
25 * and other larger sizes. Since we are unlikely to be allocate that
26 * much physically contiguous memory after the system is up and running,
27 * we preallocate a set of RMAs in early boot for KVM to use.
29 static unsigned long kvm_rma_size = 64 << 20; /* 64MB */
30 static unsigned long kvm_rma_count;
32 static int __init early_parse_rma_size(char *p)
37 kvm_rma_size = memparse(p, &p);
41 early_param("kvm_rma_size", early_parse_rma_size);
43 static int __init early_parse_rma_count(char *p)
48 kvm_rma_count = simple_strtoul(p, NULL, 0);
52 early_param("kvm_rma_count", early_parse_rma_count);
54 static struct kvmppc_rma_info *rma_info;
55 static LIST_HEAD(free_rmas);
56 static DEFINE_SPINLOCK(rma_lock);
58 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
59 Assumes POWER7 or PPC970. */
60 static inline int lpcr_rmls(unsigned long rma_size)
63 case 32ul << 20: /* 32 MB */
64 if (cpu_has_feature(CPU_FTR_ARCH_206))
65 return 8; /* only supported on POWER7 */
67 case 64ul << 20: /* 64 MB */
69 case 128ul << 20: /* 128 MB */
71 case 256ul << 20: /* 256 MB */
73 case 1ul << 30: /* 1 GB */
75 case 16ul << 30: /* 16 GB */
77 case 256ul << 30: /* 256 GB */
85 * Called at boot time while the bootmem allocator is active,
86 * to allocate contiguous physical memory for the real memory
89 void __init kvm_rma_init(void)
92 unsigned long j, npages;
96 /* Only do this on PPC970 in HV mode */
97 if (!cpu_has_feature(CPU_FTR_HVMODE) ||
98 !cpu_has_feature(CPU_FTR_ARCH_201))
101 if (!kvm_rma_size || !kvm_rma_count)
104 /* Check that the requested size is one supported in hardware */
105 if (lpcr_rmls(kvm_rma_size) < 0) {
106 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
110 npages = kvm_rma_size >> PAGE_SHIFT;
111 rma_info = alloc_bootmem(kvm_rma_count * sizeof(struct kvmppc_rma_info));
112 for (i = 0; i < kvm_rma_count; ++i) {
113 rma = alloc_bootmem_align(kvm_rma_size, kvm_rma_size);
114 pr_info("Allocated KVM RMA at %p (%ld MB)\n", rma,
116 rma_info[i].base_virt = rma;
117 rma_info[i].base_pfn = __pa(rma) >> PAGE_SHIFT;
118 rma_info[i].npages = npages;
119 list_add_tail(&rma_info[i].list, &free_rmas);
120 atomic_set(&rma_info[i].use_count, 0);
122 pg = pfn_to_page(rma_info[i].base_pfn);
123 for (j = 0; j < npages; ++j) {
124 atomic_inc(&pg->_count);
130 struct kvmppc_rma_info *kvm_alloc_rma(void)
132 struct kvmppc_rma_info *ri;
135 spin_lock(&rma_lock);
136 if (!list_empty(&free_rmas)) {
137 ri = list_first_entry(&free_rmas, struct kvmppc_rma_info, list);
139 atomic_inc(&ri->use_count);
141 spin_unlock(&rma_lock);
144 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
146 void kvm_release_rma(struct kvmppc_rma_info *ri)
148 if (atomic_dec_and_test(&ri->use_count)) {
149 spin_lock(&rma_lock);
150 list_add_tail(&ri->list, &free_rmas);
151 spin_unlock(&rma_lock);
155 EXPORT_SYMBOL_GPL(kvm_release_rma);