From 449aa906e67e57636086967bf0edc1328fd0ca9f Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Tue, 5 May 2020 16:50:00 -0400 Subject: KVM: selftests: Add KVM_SET_GUEST_DEBUG test Covers fundamental tests for KVM_SET_GUEST_DEBUG. It is very close to the debug test in kvm-unit-test, but doing it from outside the guest. Signed-off-by: Peter Xu Message-Id: <20200505205000.188252-4-peterx@redhat.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/Makefile | 1 + tools/testing/selftests/kvm/include/kvm_util.h | 2 + tools/testing/selftests/kvm/lib/kvm_util.c | 9 ++ tools/testing/selftests/kvm/x86_64/debug_regs.c | 180 ++++++++++++++++++++++++ 4 files changed, 192 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/debug_regs.c (limited to 'tools') diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 712a2ddd2a27..44b6ef513164 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -28,6 +28,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test +TEST_GEN_PROGS_x86_64 += x86_64/debug_regs TEST_GEN_PROGS_x86_64 += clear_dirty_log_test TEST_GEN_PROGS_x86_64 += demand_paging_test TEST_GEN_PROGS_x86_64 += dirty_log_test diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index a99b875f50d2..92e184a422ee 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -143,6 +143,8 @@ struct kvm_run *vcpu_state(struct kvm_vm *vm, uint32_t vcpuid); void vcpu_run(struct kvm_vm *vm, uint32_t vcpuid); int _vcpu_run(struct kvm_vm *vm, uint32_t vcpuid); void vcpu_run_complete_io(struct kvm_vm *vm, uint32_t vcpuid); +void vcpu_set_guest_debug(struct kvm_vm *vm, uint32_t vcpuid, + struct kvm_guest_debug *debug); void vcpu_set_mp_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_mp_state *mp_state); void vcpu_regs_get(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_regs *regs); diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 8a3523d4434f..9622431069bc 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1201,6 +1201,15 @@ void vcpu_run_complete_io(struct kvm_vm *vm, uint32_t vcpuid) ret, errno); } +void vcpu_set_guest_debug(struct kvm_vm *vm, uint32_t vcpuid, + struct kvm_guest_debug *debug) +{ + struct vcpu *vcpu = vcpu_find(vm, vcpuid); + int ret = ioctl(vcpu->fd, KVM_SET_GUEST_DEBUG, debug); + + TEST_ASSERT(ret == 0, "KVM_SET_GUEST_DEBUG failed: %d", ret); +} + /* * VM VCPU Set MP State * diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c new file mode 100644 index 000000000000..077f25d61d1a --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM guest debug register tests + * + * Copyright (C) 2020, Red Hat, Inc. + */ +#include +#include +#include "kvm_util.h" +#include "processor.h" + +#define VCPU_ID 0 + +/* For testing data access debug BP */ +uint32_t guest_value; + +extern unsigned char sw_bp, hw_bp, write_data, ss_start; + +static void guest_code(void) +{ + /* + * Software BP tests. + * + * NOTE: sw_bp need to be before the cmd here, because int3 is an + * exception rather than a normal trap for KVM_SET_GUEST_DEBUG (we + * capture it using the vcpu exception bitmap). + */ + asm volatile("sw_bp: int3"); + + /* Hardware instruction BP test */ + asm volatile("hw_bp: nop"); + + /* Hardware data BP test */ + asm volatile("mov $1234,%%rax;\n\t" + "mov %%rax,%0;\n\t write_data:" + : "=m" (guest_value) : : "rax"); + + /* Single step test, covers 2 basic instructions and 2 emulated */ + asm volatile("ss_start: " + "xor %%rax,%%rax\n\t" + "cpuid\n\t" + "movl $0x1a0,%%ecx\n\t" + "rdmsr\n\t" + : : : "rax", "ecx"); + + GUEST_DONE(); +} + +#define CLEAR_DEBUG() memset(&debug, 0, sizeof(debug)) +#define APPLY_DEBUG() vcpu_set_guest_debug(vm, VCPU_ID, &debug) +#define CAST_TO_RIP(v) ((unsigned long long)&(v)) +#define SET_RIP(v) do { \ + vcpu_regs_get(vm, VCPU_ID, ®s); \ + regs.rip = (v); \ + vcpu_regs_set(vm, VCPU_ID, ®s); \ + } while (0) +#define MOVE_RIP(v) SET_RIP(regs.rip + (v)); + +int main(void) +{ + struct kvm_guest_debug debug; + unsigned long long target_dr6, target_rip; + struct kvm_regs regs; + struct kvm_run *run; + struct kvm_vm *vm; + struct ucall uc; + uint64_t cmd; + int i; + /* Instruction lengths starting at ss_start */ + int ss_size[4] = { + 3, /* xor */ + 2, /* cpuid */ + 5, /* mov */ + 2, /* rdmsr */ + }; + + if (!kvm_check_cap(KVM_CAP_SET_GUEST_DEBUG)) { + print_skip("KVM_CAP_SET_GUEST_DEBUG not supported"); + return 0; + } + + vm = vm_create_default(VCPU_ID, 0, guest_code); + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid()); + run = vcpu_state(vm, VCPU_ID); + + /* Test software BPs - int3 */ + CLEAR_DEBUG(); + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP; + APPLY_DEBUG(); + vcpu_run(vm, VCPU_ID); + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && + run->debug.arch.exception == BP_VECTOR && + run->debug.arch.pc == CAST_TO_RIP(sw_bp), + "INT3: exit %d exception %d rip 0x%llx (should be 0x%llx)", + run->exit_reason, run->debug.arch.exception, + run->debug.arch.pc, CAST_TO_RIP(sw_bp)); + MOVE_RIP(1); + + /* Test instruction HW BP over DR[0-3] */ + for (i = 0; i < 4; i++) { + CLEAR_DEBUG(); + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; + debug.arch.debugreg[i] = CAST_TO_RIP(hw_bp); + debug.arch.debugreg[7] = 0x400 | (1UL << (2*i+1)); + APPLY_DEBUG(); + vcpu_run(vm, VCPU_ID); + target_dr6 = 0xffff0ff0 | (1UL << i); + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && + run->debug.arch.exception == DB_VECTOR && + run->debug.arch.pc == CAST_TO_RIP(hw_bp) && + run->debug.arch.dr6 == target_dr6, + "INS_HW_BP (DR%d): exit %d exception %d rip 0x%llx " + "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", + i, run->exit_reason, run->debug.arch.exception, + run->debug.arch.pc, CAST_TO_RIP(hw_bp), + run->debug.arch.dr6, target_dr6); + } + /* Skip "nop" */ + MOVE_RIP(1); + + /* Test data access HW BP over DR[0-3] */ + for (i = 0; i < 4; i++) { + CLEAR_DEBUG(); + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; + debug.arch.debugreg[i] = CAST_TO_RIP(guest_value); + debug.arch.debugreg[7] = 0x00000400 | (1UL << (2*i+1)) | + (0x000d0000UL << (4*i)); + APPLY_DEBUG(); + vcpu_run(vm, VCPU_ID); + target_dr6 = 0xffff0ff0 | (1UL << i); + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && + run->debug.arch.exception == DB_VECTOR && + run->debug.arch.pc == CAST_TO_RIP(write_data) && + run->debug.arch.dr6 == target_dr6, + "DATA_HW_BP (DR%d): exit %d exception %d rip 0x%llx " + "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", + i, run->exit_reason, run->debug.arch.exception, + run->debug.arch.pc, CAST_TO_RIP(write_data), + run->debug.arch.dr6, target_dr6); + /* Rollback the 4-bytes "mov" */ + MOVE_RIP(-7); + } + /* Skip the 4-bytes "mov" */ + MOVE_RIP(7); + + /* Test single step */ + target_rip = CAST_TO_RIP(ss_start); + target_dr6 = 0xffff4ff0ULL; + vcpu_regs_get(vm, VCPU_ID, ®s); + for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) { + target_rip += ss_size[i]; + CLEAR_DEBUG(); + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP; + debug.arch.debugreg[7] = 0x00000400; + APPLY_DEBUG(); + vcpu_run(vm, VCPU_ID); + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && + run->debug.arch.exception == DB_VECTOR && + run->debug.arch.pc == target_rip && + run->debug.arch.dr6 == target_dr6, + "SINGLE_STEP[%d]: exit %d exception %d rip 0x%llx " + "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", + i, run->exit_reason, run->debug.arch.exception, + run->debug.arch.pc, target_rip, run->debug.arch.dr6, + target_dr6); + } + + /* Disable all debug controls, run to the end */ + CLEAR_DEBUG(); + APPLY_DEBUG(); + + vcpu_run(vm, VCPU_ID); + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, "KVM_EXIT_IO"); + cmd = get_ucall(vm, VCPU_ID, &uc); + TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE"); + + kvm_vm_free(vm); + + return 0; +} -- cgit v1.2.3 From 45981dedf555bd66d86ccb51e4049d9f7ec45bd5 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 May 2020 05:59:39 -0400 Subject: KVM: VMX: pass correct DR6 for GD userspace exit 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 --- arch/x86/kvm/vmx/vmx.c | 2 +- tools/testing/selftests/kvm/x86_64/debug_regs.c | 24 +++++++++++++++++++++++- 2 files changed, 24 insertions(+), 2 deletions(-) (limited to 'tools') diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e2b71b0cdfce..e45cf89c5821 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4927,7 +4927,7 @@ static int handle_dr(struct kvm_vcpu *vcpu) * guest debugging itself. */ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) { - vcpu->run->debug.arch.dr6 = vcpu->arch.dr6; + vcpu->run->debug.arch.dr6 = DR6_BD | DR6_RTM | DR6_FIXED_1; vcpu->run->debug.arch.dr7 = dr7; vcpu->run->debug.arch.pc = kvm_get_linear_rip(vcpu); vcpu->run->debug.arch.exception = DB_VECTOR; diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c index 077f25d61d1a..8162c58a1234 100644 --- a/tools/testing/selftests/kvm/x86_64/debug_regs.c +++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c @@ -11,10 +11,13 @@ #define VCPU_ID 0 +#define DR6_BD (1 << 13) +#define DR7_GD (1 << 13) + /* For testing data access debug BP */ uint32_t guest_value; -extern unsigned char sw_bp, hw_bp, write_data, ss_start; +extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start; static void guest_code(void) { @@ -43,6 +46,8 @@ static void guest_code(void) "rdmsr\n\t" : : : "rax", "ecx"); + /* DR6.BD test */ + asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax"); GUEST_DONE(); } @@ -165,6 +170,23 @@ int main(void) target_dr6); } + /* Finally test global disable */ + CLEAR_DEBUG(); + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP; + debug.arch.debugreg[7] = 0x400 | DR7_GD; + APPLY_DEBUG(); + vcpu_run(vm, VCPU_ID); + target_dr6 = 0xffff0ff0 | DR6_BD; + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG && + run->debug.arch.exception == DB_VECTOR && + run->debug.arch.pc == CAST_TO_RIP(bd_start) && + run->debug.arch.dr6 == target_dr6, + "DR7.GD: exit %d exception %d rip 0x%llx " + "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)", + run->exit_reason, run->debug.arch.exception, + run->debug.arch.pc, target_rip, run->debug.arch.dr6, + target_dr6); + /* Disable all debug controls, run to the end */ CLEAR_DEBUG(); APPLY_DEBUG(); -- cgit v1.2.3