45981dedf5
When KVM_EXIT_DEBUG is raised for the disabled-breakpoints case (DR7.GD), DR6 was incorrectly copied from the value in the VM. Instead, DR6.BD should be set in order to catch this case. On AMD this does not need any special code because the processor triggers a #DB exception that is intercepted. However, the testcase would fail without the previous patch because both DR6.BS and DR6.BD would be set. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
203 lines
6.1 KiB
C
203 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* KVM guest debug register tests
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*
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* Copyright (C) 2020, Red Hat, Inc.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "kvm_util.h"
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#include "processor.h"
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#define VCPU_ID 0
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#define DR6_BD (1 << 13)
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#define DR7_GD (1 << 13)
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/* For testing data access debug BP */
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uint32_t guest_value;
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extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
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static void guest_code(void)
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{
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/*
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* Software BP tests.
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*
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* NOTE: sw_bp need to be before the cmd here, because int3 is an
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* exception rather than a normal trap for KVM_SET_GUEST_DEBUG (we
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* capture it using the vcpu exception bitmap).
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*/
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asm volatile("sw_bp: int3");
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/* Hardware instruction BP test */
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asm volatile("hw_bp: nop");
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/* Hardware data BP test */
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asm volatile("mov $1234,%%rax;\n\t"
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"mov %%rax,%0;\n\t write_data:"
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: "=m" (guest_value) : : "rax");
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/* Single step test, covers 2 basic instructions and 2 emulated */
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asm volatile("ss_start: "
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"xor %%rax,%%rax\n\t"
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"cpuid\n\t"
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"movl $0x1a0,%%ecx\n\t"
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"rdmsr\n\t"
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: : : "rax", "ecx");
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/* DR6.BD test */
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asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
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GUEST_DONE();
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}
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#define CLEAR_DEBUG() memset(&debug, 0, sizeof(debug))
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#define APPLY_DEBUG() vcpu_set_guest_debug(vm, VCPU_ID, &debug)
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#define CAST_TO_RIP(v) ((unsigned long long)&(v))
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#define SET_RIP(v) do { \
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vcpu_regs_get(vm, VCPU_ID, ®s); \
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regs.rip = (v); \
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vcpu_regs_set(vm, VCPU_ID, ®s); \
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} while (0)
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#define MOVE_RIP(v) SET_RIP(regs.rip + (v));
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int main(void)
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{
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struct kvm_guest_debug debug;
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unsigned long long target_dr6, target_rip;
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struct kvm_regs regs;
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struct kvm_run *run;
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struct kvm_vm *vm;
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struct ucall uc;
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uint64_t cmd;
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int i;
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/* Instruction lengths starting at ss_start */
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int ss_size[4] = {
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3, /* xor */
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2, /* cpuid */
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5, /* mov */
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2, /* rdmsr */
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};
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if (!kvm_check_cap(KVM_CAP_SET_GUEST_DEBUG)) {
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print_skip("KVM_CAP_SET_GUEST_DEBUG not supported");
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return 0;
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}
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vm = vm_create_default(VCPU_ID, 0, guest_code);
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vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
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run = vcpu_state(vm, VCPU_ID);
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/* Test software BPs - int3 */
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CLEAR_DEBUG();
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debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
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run->debug.arch.exception == BP_VECTOR &&
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run->debug.arch.pc == CAST_TO_RIP(sw_bp),
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"INT3: exit %d exception %d rip 0x%llx (should be 0x%llx)",
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run->exit_reason, run->debug.arch.exception,
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run->debug.arch.pc, CAST_TO_RIP(sw_bp));
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MOVE_RIP(1);
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/* Test instruction HW BP over DR[0-3] */
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for (i = 0; i < 4; i++) {
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CLEAR_DEBUG();
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debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
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debug.arch.debugreg[i] = CAST_TO_RIP(hw_bp);
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debug.arch.debugreg[7] = 0x400 | (1UL << (2*i+1));
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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target_dr6 = 0xffff0ff0 | (1UL << i);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
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run->debug.arch.exception == DB_VECTOR &&
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run->debug.arch.pc == CAST_TO_RIP(hw_bp) &&
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run->debug.arch.dr6 == target_dr6,
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"INS_HW_BP (DR%d): exit %d exception %d rip 0x%llx "
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"(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
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i, run->exit_reason, run->debug.arch.exception,
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run->debug.arch.pc, CAST_TO_RIP(hw_bp),
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run->debug.arch.dr6, target_dr6);
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}
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/* Skip "nop" */
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MOVE_RIP(1);
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/* Test data access HW BP over DR[0-3] */
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for (i = 0; i < 4; i++) {
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CLEAR_DEBUG();
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debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
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debug.arch.debugreg[i] = CAST_TO_RIP(guest_value);
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debug.arch.debugreg[7] = 0x00000400 | (1UL << (2*i+1)) |
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(0x000d0000UL << (4*i));
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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target_dr6 = 0xffff0ff0 | (1UL << i);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
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run->debug.arch.exception == DB_VECTOR &&
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run->debug.arch.pc == CAST_TO_RIP(write_data) &&
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run->debug.arch.dr6 == target_dr6,
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"DATA_HW_BP (DR%d): exit %d exception %d rip 0x%llx "
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"(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
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i, run->exit_reason, run->debug.arch.exception,
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run->debug.arch.pc, CAST_TO_RIP(write_data),
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run->debug.arch.dr6, target_dr6);
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/* Rollback the 4-bytes "mov" */
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MOVE_RIP(-7);
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}
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/* Skip the 4-bytes "mov" */
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MOVE_RIP(7);
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/* Test single step */
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target_rip = CAST_TO_RIP(ss_start);
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target_dr6 = 0xffff4ff0ULL;
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vcpu_regs_get(vm, VCPU_ID, ®s);
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for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) {
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target_rip += ss_size[i];
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CLEAR_DEBUG();
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debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
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debug.arch.debugreg[7] = 0x00000400;
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
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run->debug.arch.exception == DB_VECTOR &&
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run->debug.arch.pc == target_rip &&
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run->debug.arch.dr6 == target_dr6,
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"SINGLE_STEP[%d]: exit %d exception %d rip 0x%llx "
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"(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
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i, run->exit_reason, run->debug.arch.exception,
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run->debug.arch.pc, target_rip, run->debug.arch.dr6,
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target_dr6);
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}
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/* Finally test global disable */
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CLEAR_DEBUG();
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debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
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debug.arch.debugreg[7] = 0x400 | DR7_GD;
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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target_dr6 = 0xffff0ff0 | DR6_BD;
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TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
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run->debug.arch.exception == DB_VECTOR &&
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run->debug.arch.pc == CAST_TO_RIP(bd_start) &&
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run->debug.arch.dr6 == target_dr6,
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"DR7.GD: exit %d exception %d rip 0x%llx "
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"(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
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run->exit_reason, run->debug.arch.exception,
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run->debug.arch.pc, target_rip, run->debug.arch.dr6,
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target_dr6);
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/* Disable all debug controls, run to the end */
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CLEAR_DEBUG();
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APPLY_DEBUG();
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vcpu_run(vm, VCPU_ID);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, "KVM_EXIT_IO");
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cmd = get_ucall(vm, VCPU_ID, &uc);
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TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE");
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kvm_vm_free(vm);
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return 0;
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}
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