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.
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>
20 #include <asm/cputable.h>
21 #include <asm/kvm_ppc.h>
22 #include <asm/kvm_book3s.h>
24 #define KVM_CMA_CHUNK_ORDER 18
27 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
28 * should be power of 2.
30 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
32 * By default we reserve 5% of memory for hash pagetable allocation.
34 static unsigned long kvm_cma_resv_ratio = 5;
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.
44 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
45 EXPORT_SYMBOL_GPL(kvm_rma_pages);
47 static struct cma *kvm_cma;
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)
54 case 32ul << 20: /* 32 MB */
55 if (cpu_has_feature(CPU_FTR_ARCH_206))
56 return 8; /* only supported on POWER7 */
58 case 64ul << 20: /* 64 MB */
60 case 128ul << 20: /* 128 MB */
62 case 256ul << 20: /* 256 MB */
64 case 1ul << 30: /* 1 GB */
66 case 16ul << 30: /* 16 GB */
68 case 256ul << 30: /* 256 GB */
75 static int __init early_parse_rma_size(char *p)
77 unsigned long kvm_rma_size;
79 pr_debug("%s(%s)\n", __func__, p);
82 kvm_rma_size = memparse(p, &p);
84 * Check that the requested size is one supported in hardware
86 if (lpcr_rmls(kvm_rma_size) < 0) {
87 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
90 kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
93 early_param("kvm_rma_size", early_parse_rma_size);
95 struct kvm_rma_info *kvm_alloc_rma()
98 struct kvm_rma_info *ri;
100 ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
103 page = cma_alloc(kvm_cma, kvm_rma_pages, order_base_2(kvm_rma_pages));
106 atomic_set(&ri->use_count, 1);
107 ri->base_pfn = page_to_pfn(page);
113 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
115 void kvm_release_rma(struct kvm_rma_info *ri)
117 if (atomic_dec_and_test(&ri->use_count)) {
118 cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
122 EXPORT_SYMBOL_GPL(kvm_release_rma);
124 static int __init early_parse_kvm_cma_resv(char *p)
126 pr_debug("%s(%s)\n", __func__, p);
129 return kstrtoul(p, 0, &kvm_cma_resv_ratio);
131 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
133 struct page *kvm_alloc_hpt(unsigned long nr_pages)
135 unsigned long align_pages = HPT_ALIGN_PAGES;
137 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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));
144 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
146 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
148 cma_release(kvm_cma, page, nr_pages);
150 EXPORT_SYMBOL_GPL(kvm_release_hpt);
153 * kvm_cma_reserve() - reserve area for kvm hash pagetable
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
160 void __init kvm_cma_reserve(void)
162 unsigned long align_size;
163 struct memblock_region *reg;
164 phys_addr_t selected_size = 0;
167 * We need CMA reservation only when we are in HV mode
169 if (!cpu_has_feature(CPU_FTR_HVMODE))
172 * We cannot use memblock_phys_mem_size() here, because
173 * memblock_analyze() has not been called yet.
175 for_each_memblock(memory, reg)
176 selected_size += memblock_region_memory_end_pfn(reg) -
177 memblock_region_memory_base_pfn(reg);
179 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
181 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
182 (unsigned long)selected_size / SZ_1M);
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.
187 if (!cpu_has_feature(CPU_FTR_ARCH_206))
188 align_size = __rounddown_pow_of_two(selected_size);
190 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
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);
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.
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().
205 static atomic_t hv_vm_count;
207 void kvm_hv_vm_activated(void)
210 atomic_inc(&hv_vm_count);
213 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
215 void kvm_hv_vm_deactivated(void)
218 atomic_dec(&hv_vm_count);
221 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
223 bool kvm_hv_mode_active(void)
225 return atomic_read(&hv_vm_count) != 0;
228 extern int hcall_real_table[], hcall_real_table_end[];
230 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd)
233 if (cmd < hcall_real_table_end - hcall_real_table &&
234 hcall_real_table[cmd])
239 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode);