218 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * KVM guest debug register tests4 *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 0xAA17 18/* For testing data access debug BP */19uint32_t guest_value;20 21extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;22 23static 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 an34 * exception rather than a normal trap for KVM_SET_GUEST_DEBUG (we35 * 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 emulated49 *50 * Enable interrupts during the single stepping to see that pending51 * interrupt we raised is not handled due to KVM_GUESTDBG_BLOCKIRQ.52 *53 * Write MSR_IA32_TSC_DEADLINE to verify that KVM's fastpath handler54 * exits to userspace due to single-step being enabled.55 */56 asm volatile("ss_start: "57 "sti\n\t"58 "xor %%eax,%%eax\n\t"59 "cpuid\n\t"60 "movl $" __stringify(MSR_IA32_TSC_DEADLINE) ", %%ecx\n\t"61 "wrmsr\n\t"62 "cli\n\t"63 : : : "eax", "ebx", "ecx", "edx");64 65 /* DR6.BD test */66 asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");67 GUEST_DONE();68}69 70#define CAST_TO_RIP(v) ((unsigned long long)&(v))71 72static void vcpu_skip_insn(struct kvm_vcpu *vcpu, int insn_len)73{74 struct kvm_regs regs;75 76 vcpu_regs_get(vcpu, ®s);77 regs.rip += insn_len;78 vcpu_regs_set(vcpu, ®s);79}80 81int main(void)82{83 struct kvm_guest_debug debug;84 unsigned long long target_dr6, target_rip;85 struct kvm_vcpu *vcpu;86 struct kvm_run *run;87 struct kvm_vm *vm;88 struct ucall uc;89 uint64_t cmd;90 int i;91 /* Instruction lengths starting at ss_start */92 int ss_size[6] = {93 1, /* sti*/94 2, /* xor */95 2, /* cpuid */96 5, /* mov */97 2, /* rdmsr */98 1, /* cli */99 };100 101 TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG));102 103 vm = vm_create_with_one_vcpu(&vcpu, guest_code);104 run = vcpu->run;105 106 /* Test software BPs - int3 */107 memset(&debug, 0, sizeof(debug));108 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;109 vcpu_guest_debug_set(vcpu, &debug);110 vcpu_run(vcpu);111 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&112 run->debug.arch.exception == BP_VECTOR &&113 run->debug.arch.pc == CAST_TO_RIP(sw_bp),114 "INT3: exit %d exception %d rip 0x%llx (should be 0x%llx)",115 run->exit_reason, run->debug.arch.exception,116 run->debug.arch.pc, CAST_TO_RIP(sw_bp));117 vcpu_skip_insn(vcpu, 1);118 119 /* Test instruction HW BP over DR[0-3] */120 for (i = 0; i < 4; i++) {121 memset(&debug, 0, sizeof(debug));122 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;123 debug.arch.debugreg[i] = CAST_TO_RIP(hw_bp);124 debug.arch.debugreg[7] = 0x400 | (1UL << (2*i+1));125 vcpu_guest_debug_set(vcpu, &debug);126 vcpu_run(vcpu);127 target_dr6 = 0xffff0ff0 | (1UL << i);128 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&129 run->debug.arch.exception == DB_VECTOR &&130 run->debug.arch.pc == CAST_TO_RIP(hw_bp) &&131 run->debug.arch.dr6 == target_dr6,132 "INS_HW_BP (DR%d): exit %d exception %d rip 0x%llx "133 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",134 i, run->exit_reason, run->debug.arch.exception,135 run->debug.arch.pc, CAST_TO_RIP(hw_bp),136 run->debug.arch.dr6, target_dr6);137 }138 /* Skip "nop" */139 vcpu_skip_insn(vcpu, 1);140 141 /* Test data access HW BP over DR[0-3] */142 for (i = 0; i < 4; i++) {143 memset(&debug, 0, sizeof(debug));144 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;145 debug.arch.debugreg[i] = CAST_TO_RIP(guest_value);146 debug.arch.debugreg[7] = 0x00000400 | (1UL << (2*i+1)) |147 (0x000d0000UL << (4*i));148 vcpu_guest_debug_set(vcpu, &debug);149 vcpu_run(vcpu);150 target_dr6 = 0xffff0ff0 | (1UL << i);151 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&152 run->debug.arch.exception == DB_VECTOR &&153 run->debug.arch.pc == CAST_TO_RIP(write_data) &&154 run->debug.arch.dr6 == target_dr6,155 "DATA_HW_BP (DR%d): exit %d exception %d rip 0x%llx "156 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",157 i, run->exit_reason, run->debug.arch.exception,158 run->debug.arch.pc, CAST_TO_RIP(write_data),159 run->debug.arch.dr6, target_dr6);160 /* Rollback the 4-bytes "mov" */161 vcpu_skip_insn(vcpu, -7);162 }163 /* Skip the 4-bytes "mov" */164 vcpu_skip_insn(vcpu, 7);165 166 /* Test single step */167 target_rip = CAST_TO_RIP(ss_start);168 target_dr6 = 0xffff4ff0ULL;169 for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) {170 target_rip += ss_size[i];171 memset(&debug, 0, sizeof(debug));172 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP |173 KVM_GUESTDBG_BLOCKIRQ;174 debug.arch.debugreg[7] = 0x00000400;175 vcpu_guest_debug_set(vcpu, &debug);176 vcpu_run(vcpu);177 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&178 run->debug.arch.exception == DB_VECTOR &&179 run->debug.arch.pc == target_rip &&180 run->debug.arch.dr6 == target_dr6,181 "SINGLE_STEP[%d]: exit %d exception %d rip 0x%llx "182 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",183 i, run->exit_reason, run->debug.arch.exception,184 run->debug.arch.pc, target_rip, run->debug.arch.dr6,185 target_dr6);186 }187 188 /* Finally test global disable */189 memset(&debug, 0, sizeof(debug));190 debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;191 debug.arch.debugreg[7] = 0x400 | DR7_GD;192 vcpu_guest_debug_set(vcpu, &debug);193 vcpu_run(vcpu);194 target_dr6 = 0xffff0ff0 | DR6_BD;195 TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&196 run->debug.arch.exception == DB_VECTOR &&197 run->debug.arch.pc == CAST_TO_RIP(bd_start) &&198 run->debug.arch.dr6 == target_dr6,199 "DR7.GD: exit %d exception %d rip 0x%llx "200 "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",201 run->exit_reason, run->debug.arch.exception,202 run->debug.arch.pc, target_rip, run->debug.arch.dr6,203 target_dr6);204 205 /* Disable all debug controls, run to the end */206 memset(&debug, 0, sizeof(debug));207 vcpu_guest_debug_set(vcpu, &debug);208 209 vcpu_run(vcpu);210 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);211 cmd = get_ucall(vcpu, &uc);212 TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE");213 214 kvm_vm_free(vm);215 216 return 0;217}218