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>
19 #include <linux/cma.h>
20 #include <linux/bitops.h>
22 #include <asm/cputable.h>
23 #include <asm/kvm_ppc.h>
24 #include <asm/kvm_book3s.h>
26 #define KVM_CMA_CHUNK_ORDER 18
29 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
30 * should be power of 2.
32 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
34 * By default we reserve 5% of memory for hash pagetable allocation.
36 static unsigned long kvm_cma_resv_ratio = 5;
38 static struct cma *kvm_cma;
40 static int __init early_parse_kvm_cma_resv(char *p)
42 pr_debug("%s(%s)\n", __func__, p);
45 return kstrtoul(p, 0, &kvm_cma_resv_ratio);
47 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
49 struct page *kvm_alloc_hpt(unsigned long nr_pages)
51 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
53 return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_ALIGN_PAGES));
55 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
57 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
59 cma_release(kvm_cma, page, nr_pages);
61 EXPORT_SYMBOL_GPL(kvm_release_hpt);
64 * kvm_cma_reserve() - reserve area for kvm hash pagetable
66 * This function reserves memory from early allocator. It should be
67 * called by arch specific code once the early allocator (memblock or bootmem)
68 * has been activated and all other subsystems have already allocated/reserved
71 void __init kvm_cma_reserve(void)
73 unsigned long align_size;
74 struct memblock_region *reg;
75 phys_addr_t selected_size = 0;
78 * We need CMA reservation only when we are in HV mode
80 if (!cpu_has_feature(CPU_FTR_HVMODE))
83 * We cannot use memblock_phys_mem_size() here, because
84 * memblock_analyze() has not been called yet.
86 for_each_memblock(memory, reg)
87 selected_size += memblock_region_memory_end_pfn(reg) -
88 memblock_region_memory_base_pfn(reg);
90 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
92 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
93 (unsigned long)selected_size / SZ_1M);
94 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
95 cma_declare_contiguous(0, selected_size, 0, align_size,
96 KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
101 * Real-mode H_CONFER implementation.
102 * We check if we are the only vcpu out of this virtual core
103 * still running in the guest and not ceded. If so, we pop up
104 * to the virtual-mode implementation; if not, just return to
107 long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target,
108 unsigned int yield_count)
110 struct kvmppc_vcore *vc = vcpu->arch.vcore;
113 int threads_conferring;
114 u64 stop = get_tb() + 10 * tb_ticks_per_usec;
115 int rv = H_SUCCESS; /* => don't yield */
117 set_bit(vcpu->arch.ptid, &vc->conferring_threads);
118 while ((get_tb() < stop) && (VCORE_EXIT_COUNT(vc) == 0)) {
119 threads_running = VCORE_ENTRY_COUNT(vc);
120 threads_ceded = hweight32(vc->napping_threads);
121 threads_conferring = hweight32(vc->conferring_threads);
122 if (threads_ceded + threads_conferring >= threads_running) {
123 rv = H_TOO_HARD; /* => do yield */
127 clear_bit(vcpu->arch.ptid, &vc->conferring_threads);
132 * When running HV mode KVM we need to block certain operations while KVM VMs
133 * exist in the system. We use a counter of VMs to track this.
135 * One of the operations we need to block is onlining of secondaries, so we
136 * protect hv_vm_count with get/put_online_cpus().
138 static atomic_t hv_vm_count;
140 void kvm_hv_vm_activated(void)
143 atomic_inc(&hv_vm_count);
146 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
148 void kvm_hv_vm_deactivated(void)
151 atomic_dec(&hv_vm_count);
154 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
156 bool kvm_hv_mode_active(void)
158 return atomic_read(&hv_vm_count) != 0;
161 extern int hcall_real_table[], hcall_real_table_end[];
163 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd)
166 if (cmd < hcall_real_table_end - hcall_real_table &&
167 hcall_real_table[cmd])
172 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode);