1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * KVM guest debug register tests 4 * 5 * Copyright (C) 2020, Red Hat, Inc. 6 */ 7 #include <stdio.h> 8 #include <string.h> 9 #include "kvm_util.h" 10 #include "processor.h" 11 #include "apic.h" 12 13 #define DR6_BD (1 << 13) 14 #define DR7_GD (1 << 13) 15 16 #define IRQ_VECTOR 0xAA 17 18 /* For testing data access debug BP */ 19 uint32_t guest_value; 20 21 extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start; 22 23 static void guest_code(void) 24 { 25 /* Create a pending interrupt on current vCPU */ 26 x2apic_enable(); 27 x2apic_write_reg(APIC_ICR, APIC_DEST_SELF | APIC_INT_ASSERT | 28 APIC_DM_FIXED | IRQ_VECTOR); 29 30 /* 31 * Software BP tests. 32 * 33 * NOTE: sw_bp need to be before the cmd here, because int3 is an 34 * exception rather than a normal trap for KVM_SET_GUEST_DEBUG (we 35 * capture it using the vcpu exception bitmap). 36 */ 37 asm volatile("sw_bp: int3"); 38 39 /* Hardware instruction BP test */ 40 asm volatile("hw_bp: nop"); 41 42 /* Hardware data BP test */ 43 asm volatile("mov $1234,%%rax;\n\t" 44 "mov %%rax,%0;\n\t write_data:" 45 : "=m" (guest_value) : : "rax"); 46 47 /* 48 * Single step test, covers 2 basic instructions and 2 emulated 49 * 50 * Enable interrupts during the single stepping to see that 51 * pending interrupt we raised is not handled due to KVM_GUESTDBG_BLOCKIRQ 52 */ 53 asm volatile("ss_start: " 54 "sti\n\t" 55 "xor %%eax,%%eax\n\t" 56 "cpuid\n\t" 57 "movl $0x1a0,%%ecx\n\t" 58 "rdmsr\n\t" 59 "cli\n\t" 60 : : : "eax", "ebx", "ecx", "edx"); 61 62 /* DR6.BD test */ 63 asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax"); 64 GUEST_DONE(); 65 } 66 67 #define CAST_TO_RIP(v) ((unsigned long long)&(v)) 68 69 static void vcpu_skip_insn(struct kvm_vcpu *vcpu, int insn_len) 70 { 71 struct kvm_regs regs; 72 73 vcpu_regs_get(vcpu, ®s); 74 regs.rip += insn_len; 75 vcpu_regs_set(vcpu, ®s); 76 } 77 78 int main(void) 79 { 80 struct kvm_guest_debug debug; 81 unsigned long long target_dr6, target_rip; 82 struct kvm_vcpu *vcpu; 83 struct kvm_run *run; 84 struct kvm_vm *vm; 85 struct ucall uc; 86 uint64_t cmd; 87 int i; 88 /* Instruction lengths starting at ss_start */ 89 int ss_size[6] = { 90 1, /* sti*/ 91 2, /* xor */ 92 2, /* cpuid */ 93 5, /* mov */ 94 2, /* rdmsr */ 95 1, /* cli */ 96 }; 97 98 TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG)); 99 100 vm = vm_create_with_one_vcpu(&vcpu, guest_code); 101 run = vcpu->run; 102 103 /* Test software BPs - int3 */ 104 memset(&debug, 0, sizeof(debug)); 105 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP; 106 vcpu_guest_debug_set(vcpu, &debug); 107 vcpu_run(vcpu); 108 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && 109 run->debug.arch.exception == BP_VECTOR && 110 run->debug.arch.pc == CAST_TO_RIP(sw_bp), 111 "INT3: exit %d exception %d rip 0x%llx (should be 0x%llx)", 112 run->exit_reason, run->debug.arch.exception, 113 run->debug.arch.pc, CAST_TO_RIP(sw_bp)); 114 vcpu_skip_insn(vcpu, 1); 115 116 /* Test instruction HW BP over DR[0-3] */ 117 for (i = 0; i < 4; i++) { 118 memset(&debug, 0, sizeof(debug)); 119 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; 120 debug.arch.debugreg[i] = CAST_TO_RIP(hw_bp); 121 debug.arch.debugreg[7] = 0x400 | (1UL << (2*i+1)); 122 vcpu_guest_debug_set(vcpu, &debug); 123 vcpu_run(vcpu); 124 target_dr6 = 0xffff0ff0 | (1UL << i); 125 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && 126 run->debug.arch.exception == DB_VECTOR && 127 run->debug.arch.pc == CAST_TO_RIP(hw_bp) && 128 run->debug.arch.dr6 == target_dr6, 129 "INS_HW_BP (DR%d): exit %d exception %d rip 0x%llx " 130 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", 131 i, run->exit_reason, run->debug.arch.exception, 132 run->debug.arch.pc, CAST_TO_RIP(hw_bp), 133 run->debug.arch.dr6, target_dr6); 134 } 135 /* Skip "nop" */ 136 vcpu_skip_insn(vcpu, 1); 137 138 /* Test data access HW BP over DR[0-3] */ 139 for (i = 0; i < 4; i++) { 140 memset(&debug, 0, sizeof(debug)); 141 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; 142 debug.arch.debugreg[i] = CAST_TO_RIP(guest_value); 143 debug.arch.debugreg[7] = 0x00000400 | (1UL << (2*i+1)) | 144 (0x000d0000UL << (4*i)); 145 vcpu_guest_debug_set(vcpu, &debug); 146 vcpu_run(vcpu); 147 target_dr6 = 0xffff0ff0 | (1UL << i); 148 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && 149 run->debug.arch.exception == DB_VECTOR && 150 run->debug.arch.pc == CAST_TO_RIP(write_data) && 151 run->debug.arch.dr6 == target_dr6, 152 "DATA_HW_BP (DR%d): exit %d exception %d rip 0x%llx " 153 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", 154 i, run->exit_reason, run->debug.arch.exception, 155 run->debug.arch.pc, CAST_TO_RIP(write_data), 156 run->debug.arch.dr6, target_dr6); 157 /* Rollback the 4-bytes "mov" */ 158 vcpu_skip_insn(vcpu, -7); 159 } 160 /* Skip the 4-bytes "mov" */ 161 vcpu_skip_insn(vcpu, 7); 162 163 /* Test single step */ 164 target_rip = CAST_TO_RIP(ss_start); 165 target_dr6 = 0xffff4ff0ULL; 166 for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) { 167 target_rip += ss_size[i]; 168 memset(&debug, 0, sizeof(debug)); 169 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP | 170 KVM_GUESTDBG_BLOCKIRQ; 171 debug.arch.debugreg[7] = 0x00000400; 172 vcpu_guest_debug_set(vcpu, &debug); 173 vcpu_run(vcpu); 174 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && 175 run->debug.arch.exception == DB_VECTOR && 176 run->debug.arch.pc == target_rip && 177 run->debug.arch.dr6 == target_dr6, 178 "SINGLE_STEP[%d]: exit %d exception %d rip 0x%llx " 179 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", 180 i, run->exit_reason, run->debug.arch.exception, 181 run->debug.arch.pc, target_rip, run->debug.arch.dr6, 182 target_dr6); 183 } 184 185 /* Finally test global disable */ 186 memset(&debug, 0, sizeof(debug)); 187 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; 188 debug.arch.debugreg[7] = 0x400 | DR7_GD; 189 vcpu_guest_debug_set(vcpu, &debug); 190 vcpu_run(vcpu); 191 target_dr6 = 0xffff0ff0 | DR6_BD; 192 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && 193 run->debug.arch.exception == DB_VECTOR && 194 run->debug.arch.pc == CAST_TO_RIP(bd_start) && 195 run->debug.arch.dr6 == target_dr6, 196 "DR7.GD: exit %d exception %d rip 0x%llx " 197 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", 198 run->exit_reason, run->debug.arch.exception, 199 run->debug.arch.pc, target_rip, run->debug.arch.dr6, 200 target_dr6); 201 202 /* Disable all debug controls, run to the end */ 203 memset(&debug, 0, sizeof(debug)); 204 vcpu_guest_debug_set(vcpu, &debug); 205 206 vcpu_run(vcpu); 207 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, "KVM_EXIT_IO"); 208 cmd = get_ucall(vcpu, &uc); 209 TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE"); 210 211 kvm_vm_free(vm); 212 213 return 0; 214 } 215