/* * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved. * * Authors: * Alexander Graf * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include #include #include #include #include #include #include #include #define KVM_MAGIC_PAGE (-4096L) #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x) #define KVM_INST_LWZ 0x80000000 #define KVM_INST_STW 0x90000000 #define KVM_INST_LD 0xe8000000 #define KVM_INST_STD 0xf8000000 #define KVM_INST_NOP 0x60000000 #define KVM_INST_B 0x48000000 #define KVM_INST_B_MASK 0x03ffffff #define KVM_INST_B_MAX 0x01ffffff #define KVM_MASK_RT 0x03e00000 #define KVM_INST_MFMSR 0x7c0000a6 #define KVM_INST_MFSPR_SPRG0 0x7c1042a6 #define KVM_INST_MFSPR_SPRG1 0x7c1142a6 #define KVM_INST_MFSPR_SPRG2 0x7c1242a6 #define KVM_INST_MFSPR_SPRG3 0x7c1342a6 #define KVM_INST_MFSPR_SRR0 0x7c1a02a6 #define KVM_INST_MFSPR_SRR1 0x7c1b02a6 #define KVM_INST_MFSPR_DAR 0x7c1302a6 #define KVM_INST_MFSPR_DSISR 0x7c1202a6 #define KVM_INST_MTSPR_SPRG0 0x7c1043a6 #define KVM_INST_MTSPR_SPRG1 0x7c1143a6 #define KVM_INST_MTSPR_SPRG2 0x7c1243a6 #define KVM_INST_MTSPR_SPRG3 0x7c1343a6 #define KVM_INST_MTSPR_SRR0 0x7c1a03a6 #define KVM_INST_MTSPR_SRR1 0x7c1b03a6 #define KVM_INST_MTSPR_DAR 0x7c1303a6 #define KVM_INST_MTSPR_DSISR 0x7c1203a6 #define KVM_INST_TLBSYNC 0x7c00046c static bool kvm_patching_worked = true; static char kvm_tmp[1024 * 1024]; static int kvm_tmp_index; static inline void kvm_patch_ins(u32 *inst, u32 new_inst) { *inst = new_inst; flush_icache_range((ulong)inst, (ulong)inst + 4); } static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt) { #ifdef CONFIG_64BIT kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc)); #else kvm_patch_ins(inst, KVM_INST_LWZ | rt | ((addr + 4) & 0x0000fffc)); #endif } static void kvm_patch_ins_lwz(u32 *inst, long addr, u32 rt) { kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000ffff)); } static void kvm_patch_ins_std(u32 *inst, long addr, u32 rt) { #ifdef CONFIG_64BIT kvm_patch_ins(inst, KVM_INST_STD | rt | (addr & 0x0000fffc)); #else kvm_patch_ins(inst, KVM_INST_STW | rt | ((addr + 4) & 0x0000fffc)); #endif } static void kvm_patch_ins_stw(u32 *inst, long addr, u32 rt) { kvm_patch_ins(inst, KVM_INST_STW | rt | (addr & 0x0000fffc)); } static void kvm_patch_ins_nop(u32 *inst) { kvm_patch_ins(inst, KVM_INST_NOP); } static void kvm_patch_ins_b(u32 *inst, int addr) { #ifdef CONFIG_RELOCATABLE /* On relocatable kernels interrupts handlers and our code can be in different regions, so we don't patch them */ extern u32 __end_interrupts; if ((ulong)inst < (ulong)&__end_interrupts) return; #endif kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK)); } static u32 *kvm_alloc(int len) { u32 *p; if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) { printk(KERN_ERR "KVM: No more space (%d + %d)\n", kvm_tmp_index, len); kvm_patching_worked = false; return NULL; } p = (void*)&kvm_tmp[kvm_tmp_index]; kvm_tmp_index += len; return p; } static void kvm_map_magic_page(void *data) { kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE, KVM_MAGIC_PAGE, /* Physical Address */ KVM_MAGIC_PAGE); /* Effective Address */ } static void kvm_check_ins(u32 *inst) { u32 _inst = *inst; u32 inst_no_rt = _inst & ~KVM_MASK_RT; u32 inst_rt = _inst & KVM_MASK_RT; switch (inst_no_rt) { /* Loads */ case KVM_INST_MFMSR: kvm_patch_ins_ld(inst, magic_var(msr), inst_rt); break; case KVM_INST_MFSPR_SPRG0: kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt); break; case KVM_INST_MFSPR_SPRG1: kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt); break; case KVM_INST_MFSPR_SPRG2: kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt); break; case KVM_INST_MFSPR_SPRG3: kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt); break; case KVM_INST_MFSPR_SRR0: kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt); break; case KVM_INST_MFSPR_SRR1: kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt); break; case KVM_INST_MFSPR_DAR: kvm_patch_ins_ld(inst, magic_var(dar), inst_rt); break; case KVM_INST_MFSPR_DSISR: kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt); break; /* Stores */ case KVM_INST_MTSPR_SPRG0: kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt); break; case KVM_INST_MTSPR_SPRG1: kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt); break; case KVM_INST_MTSPR_SPRG2: kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt); break; case KVM_INST_MTSPR_SPRG3: kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt); break; case KVM_INST_MTSPR_SRR0: kvm_patch_ins_std(inst, magic_var(srr0), inst_rt); break; case KVM_INST_MTSPR_SRR1: kvm_patch_ins_std(inst, magic_var(srr1), inst_rt); break; case KVM_INST_MTSPR_DAR: kvm_patch_ins_std(inst, magic_var(dar), inst_rt); break; case KVM_INST_MTSPR_DSISR: kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt); break; /* Nops */ case KVM_INST_TLBSYNC: kvm_patch_ins_nop(inst); break; } switch (_inst) { } } static void kvm_use_magic_page(void) { u32 *p; u32 *start, *end; u32 tmp; /* Tell the host to map the magic page to -4096 on all CPUs */ on_each_cpu(kvm_map_magic_page, NULL, 1); /* Quick self-test to see if the mapping works */ if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) { kvm_patching_worked = false; return; } /* Now loop through all code and find instructions */ start = (void*)_stext; end = (void*)_etext; for (p = start; p < end; p++) kvm_check_ins(p); printk(KERN_INFO "KVM: Live patching for a fast VM %s\n", kvm_patching_worked ? "worked" : "failed"); } unsigned long kvm_hypercall(unsigned long *in, unsigned long *out, unsigned long nr) { unsigned long register r0 asm("r0"); unsigned long register r3 asm("r3") = in[0]; unsigned long register r4 asm("r4") = in[1]; unsigned long register r5 asm("r5") = in[2]; unsigned long register r6 asm("r6") = in[3]; unsigned long register r7 asm("r7") = in[4]; unsigned long register r8 asm("r8") = in[5]; unsigned long register r9 asm("r9") = in[6]; unsigned long register r10 asm("r10") = in[7]; unsigned long register r11 asm("r11") = nr; unsigned long register r12 asm("r12"); asm volatile("bl kvm_hypercall_start" : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6), "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11), "=r"(r12) : "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8), "r"(r9), "r"(r10), "r"(r11) : "memory", "cc", "xer", "ctr", "lr"); out[0] = r4; out[1] = r5; out[2] = r6; out[3] = r7; out[4] = r8; out[5] = r9; out[6] = r10; out[7] = r11; return r3; } EXPORT_SYMBOL_GPL(kvm_hypercall); static int kvm_para_setup(void) { extern u32 kvm_hypercall_start; struct device_node *hyper_node; u32 *insts; int len, i; hyper_node = of_find_node_by_path("/hypervisor"); if (!hyper_node) return -1; insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len); if (len % 4) return -1; if (len > (4 * 4)) return -1; for (i = 0; i < (len / 4); i++) kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]); return 0; } static __init void kvm_free_tmp(void) { unsigned long start, end; start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK; end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK; /* Free the tmp space we don't need */ for (; start < end; start += PAGE_SIZE) { ClearPageReserved(virt_to_page(start)); init_page_count(virt_to_page(start)); free_page(start); totalram_pages++; } } static int __init kvm_guest_init(void) { if (!kvm_para_available()) goto free_tmp; if (kvm_para_setup()) goto free_tmp; if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE)) kvm_use_magic_page(); free_tmp: kvm_free_tmp(); return 0; } postcore_initcall(kvm_guest_init);