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/cpu.h> 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> 19 #include <linux/bitops.h> 20 21 #include <asm/cputable.h> 22 #include <asm/kvm_ppc.h> 23 #include <asm/kvm_book3s.h> 24 #include <asm/archrandom.h> 25 #include <asm/xics.h> 26 #include <asm/dbell.h> 27 #include <asm/cputhreads.h> 28 29 #define KVM_CMA_CHUNK_ORDER 18 30 31 /* 32 * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206) 33 * should be power of 2. 34 */ 35 #define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */ 36 /* 37 * By default we reserve 5% of memory for hash pagetable allocation. 38 */ 39 static unsigned long kvm_cma_resv_ratio = 5; 40 41 static struct cma *kvm_cma; 42 43 static int __init early_parse_kvm_cma_resv(char *p) 44 { 45 pr_debug("%s(%s)\n", __func__, p); 46 if (!p) 47 return -EINVAL; 48 return kstrtoul(p, 0, &kvm_cma_resv_ratio); 49 } 50 early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv); 51 52 struct page *kvm_alloc_hpt(unsigned long nr_pages) 53 { 54 VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); 55 56 return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_ALIGN_PAGES)); 57 } 58 EXPORT_SYMBOL_GPL(kvm_alloc_hpt); 59 60 void kvm_release_hpt(struct page *page, unsigned long nr_pages) 61 { 62 cma_release(kvm_cma, page, nr_pages); 63 } 64 EXPORT_SYMBOL_GPL(kvm_release_hpt); 65 66 /** 67 * kvm_cma_reserve() - reserve area for kvm hash pagetable 68 * 69 * This function reserves memory from early allocator. It should be 70 * called by arch specific code once the memblock allocator 71 * has been activated and all other subsystems have already allocated/reserved 72 * memory. 73 */ 74 void __init kvm_cma_reserve(void) 75 { 76 unsigned long align_size; 77 struct memblock_region *reg; 78 phys_addr_t selected_size = 0; 79 80 /* 81 * We need CMA reservation only when we are in HV mode 82 */ 83 if (!cpu_has_feature(CPU_FTR_HVMODE)) 84 return; 85 /* 86 * We cannot use memblock_phys_mem_size() here, because 87 * memblock_analyze() has not been called yet. 88 */ 89 for_each_memblock(memory, reg) 90 selected_size += memblock_region_memory_end_pfn(reg) - 91 memblock_region_memory_base_pfn(reg); 92 93 selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT; 94 if (selected_size) { 95 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 96 (unsigned long)selected_size / SZ_1M); 97 align_size = HPT_ALIGN_PAGES << PAGE_SHIFT; 98 cma_declare_contiguous(0, selected_size, 0, align_size, 99 KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma); 100 } 101 } 102 103 /* 104 * Real-mode H_CONFER implementation. 105 * We check if we are the only vcpu out of this virtual core 106 * still running in the guest and not ceded. If so, we pop up 107 * to the virtual-mode implementation; if not, just return to 108 * the guest. 109 */ 110 long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target, 111 unsigned int yield_count) 112 { 113 struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore; 114 int ptid = local_paca->kvm_hstate.ptid; 115 int threads_running; 116 int threads_ceded; 117 int threads_conferring; 118 u64 stop = get_tb() + 10 * tb_ticks_per_usec; 119 int rv = H_SUCCESS; /* => don't yield */ 120 121 set_bit(ptid, &vc->conferring_threads); 122 while ((get_tb() < stop) && !VCORE_IS_EXITING(vc)) { 123 threads_running = VCORE_ENTRY_MAP(vc); 124 threads_ceded = vc->napping_threads; 125 threads_conferring = vc->conferring_threads; 126 if ((threads_ceded | threads_conferring) == threads_running) { 127 rv = H_TOO_HARD; /* => do yield */ 128 break; 129 } 130 } 131 clear_bit(ptid, &vc->conferring_threads); 132 return rv; 133 } 134 135 /* 136 * When running HV mode KVM we need to block certain operations while KVM VMs 137 * exist in the system. We use a counter of VMs to track this. 138 * 139 * One of the operations we need to block is onlining of secondaries, so we 140 * protect hv_vm_count with get/put_online_cpus(). 141 */ 142 static atomic_t hv_vm_count; 143 144 void kvm_hv_vm_activated(void) 145 { 146 get_online_cpus(); 147 atomic_inc(&hv_vm_count); 148 put_online_cpus(); 149 } 150 EXPORT_SYMBOL_GPL(kvm_hv_vm_activated); 151 152 void kvm_hv_vm_deactivated(void) 153 { 154 get_online_cpus(); 155 atomic_dec(&hv_vm_count); 156 put_online_cpus(); 157 } 158 EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated); 159 160 bool kvm_hv_mode_active(void) 161 { 162 return atomic_read(&hv_vm_count) != 0; 163 } 164 165 extern int hcall_real_table[], hcall_real_table_end[]; 166 167 int kvmppc_hcall_impl_hv_realmode(unsigned long cmd) 168 { 169 cmd /= 4; 170 if (cmd < hcall_real_table_end - hcall_real_table && 171 hcall_real_table[cmd]) 172 return 1; 173 174 return 0; 175 } 176 EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode); 177 178 int kvmppc_hwrng_present(void) 179 { 180 return powernv_hwrng_present(); 181 } 182 EXPORT_SYMBOL_GPL(kvmppc_hwrng_present); 183 184 long kvmppc_h_random(struct kvm_vcpu *vcpu) 185 { 186 if (powernv_get_random_real_mode(&vcpu->arch.gpr[4])) 187 return H_SUCCESS; 188 189 return H_HARDWARE; 190 } 191 192 static inline void rm_writeb(unsigned long paddr, u8 val) 193 { 194 __asm__ __volatile__("stbcix %0,0,%1" 195 : : "r" (val), "r" (paddr) : "memory"); 196 } 197 198 /* 199 * Send an interrupt or message to another CPU. 200 * This can only be called in real mode. 201 * The caller needs to include any barrier needed to order writes 202 * to memory vs. the IPI/message. 203 */ 204 void kvmhv_rm_send_ipi(int cpu) 205 { 206 unsigned long xics_phys; 207 208 /* On POWER8 for IPIs to threads in the same core, use msgsnd */ 209 if (cpu_has_feature(CPU_FTR_ARCH_207S) && 210 cpu_first_thread_sibling(cpu) == 211 cpu_first_thread_sibling(raw_smp_processor_id())) { 212 unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); 213 msg |= cpu_thread_in_core(cpu); 214 __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); 215 return; 216 } 217 218 /* Else poke the target with an IPI */ 219 xics_phys = paca[cpu].kvm_hstate.xics_phys; 220 rm_writeb(xics_phys + XICS_MFRR, IPI_PRIORITY); 221 } 222 223 /* 224 * The following functions are called from the assembly code 225 * in book3s_hv_rmhandlers.S. 226 */ 227 static void kvmhv_interrupt_vcore(struct kvmppc_vcore *vc, int active) 228 { 229 int cpu = vc->pcpu; 230 231 /* Order setting of exit map vs. msgsnd/IPI */ 232 smp_mb(); 233 for (; active; active >>= 1, ++cpu) 234 if (active & 1) 235 kvmhv_rm_send_ipi(cpu); 236 } 237 238 void kvmhv_commence_exit(int trap) 239 { 240 struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore; 241 int ptid = local_paca->kvm_hstate.ptid; 242 int me, ee; 243 244 /* Set our bit in the threads-exiting-guest map in the 0xff00 245 bits of vcore->entry_exit_map */ 246 me = 0x100 << ptid; 247 do { 248 ee = vc->entry_exit_map; 249 } while (cmpxchg(&vc->entry_exit_map, ee, ee | me) != ee); 250 251 /* Are we the first here? */ 252 if ((ee >> 8) != 0) 253 return; 254 255 /* 256 * Trigger the other threads in this vcore to exit the guest. 257 * If this is a hypervisor decrementer interrupt then they 258 * will be already on their way out of the guest. 259 */ 260 if (trap != BOOK3S_INTERRUPT_HV_DECREMENTER) 261 kvmhv_interrupt_vcore(vc, ee & ~(1 << ptid)); 262 } 263