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/bootmem.h>
16 #include <linux/init.h>
17 #include <linux/memblock.h>
18 #include <linux/sizes.h>
20 #include <asm/cputable.h>
21 #include <asm/kvm_ppc.h>
22 #include <asm/kvm_book3s.h>
24 #include "book3s_hv_cma.h"
26 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
27 * should be power of 2.
29 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
31 * By default we reserve 5% of memory for hash pagetable allocation.
33 static unsigned long kvm_cma_resv_ratio = 5;
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.
43 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
44 EXPORT_SYMBOL_GPL(kvm_rma_pages);
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)
51 case 32ul << 20: /* 32 MB */
52 if (cpu_has_feature(CPU_FTR_ARCH_206))
53 return 8; /* only supported on POWER7 */
55 case 64ul << 20: /* 64 MB */
57 case 128ul << 20: /* 128 MB */
59 case 256ul << 20: /* 256 MB */
61 case 1ul << 30: /* 1 GB */
63 case 16ul << 30: /* 16 GB */
65 case 256ul << 30: /* 256 GB */
72 static int __init early_parse_rma_size(char *p)
74 unsigned long kvm_rma_size;
76 pr_debug("%s(%s)\n", __func__, p);
79 kvm_rma_size = memparse(p, &p);
81 * Check that the requested size is one supported in hardware
83 if (lpcr_rmls(kvm_rma_size) < 0) {
84 pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
87 kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
90 early_param("kvm_rma_size", early_parse_rma_size);
92 struct kvm_rma_info *kvm_alloc_rma()
95 struct kvm_rma_info *ri;
97 ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
100 page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
103 atomic_set(&ri->use_count, 1);
104 ri->base_pfn = page_to_pfn(page);
110 EXPORT_SYMBOL_GPL(kvm_alloc_rma);
112 void kvm_release_rma(struct kvm_rma_info *ri)
114 if (atomic_dec_and_test(&ri->use_count)) {
115 kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
119 EXPORT_SYMBOL_GPL(kvm_release_rma);
121 static int __init early_parse_kvm_cma_resv(char *p)
123 pr_debug("%s(%s)\n", __func__, p);
126 return kstrtoul(p, 0, &kvm_cma_resv_ratio);
128 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
130 struct page *kvm_alloc_hpt(unsigned long nr_pages)
132 unsigned long align_pages = HPT_ALIGN_PAGES;
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);
139 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
141 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
143 kvm_release_cma(page, nr_pages);
145 EXPORT_SYMBOL_GPL(kvm_release_hpt);
148 * kvm_cma_reserve() - reserve area for kvm hash pagetable
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
155 void __init kvm_cma_reserve(void)
157 unsigned long align_size;
158 struct memblock_region *reg;
159 phys_addr_t selected_size = 0;
161 * We cannot use memblock_phys_mem_size() here, because
162 * memblock_analyze() has not been called yet.
164 for_each_memblock(memory, reg)
165 selected_size += memblock_region_memory_end_pfn(reg) -
166 memblock_region_memory_base_pfn(reg);
168 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
170 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
171 (unsigned long)selected_size / SZ_1M);
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.
176 if (!cpu_has_feature(CPU_FTR_ARCH_206))
177 align_size = __rounddown_pow_of_two(selected_size);
179 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
181 align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
182 kvm_cma_declare_contiguous(selected_size, align_size);
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.
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().
193 static atomic_t hv_vm_count;
195 void kvm_hv_vm_activated(void)
198 atomic_inc(&hv_vm_count);
201 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
203 void kvm_hv_vm_deactivated(void)
206 atomic_dec(&hv_vm_count);
209 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
211 bool kvm_hv_mode_active(void)
213 return atomic_read(&hv_vm_count) != 0;