summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/kvm/x86/debug_regs.c
diff options
context:
space:
mode:
Diffstat (limited to 'tools/testing/selftests/kvm/x86/debug_regs.c')
-rw-r--r--tools/testing/selftests/kvm/x86/debug_regs.c217
1 files changed, 217 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/debug_regs.c b/tools/testing/selftests/kvm/x86/debug_regs.c
new file mode 100644
index 000000000000..2d814c1d1dc4
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/debug_regs.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM guest debug register tests
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+#include <stdio.h>
+#include <string.h>
+#include "kvm_util.h"
+#include "processor.h"
+#include "apic.h"
+
+#define DR6_BD (1 << 13)
+#define DR7_GD (1 << 13)
+
+#define IRQ_VECTOR 0xAA
+
+/* For testing data access debug BP */
+uint32_t guest_value;
+
+extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
+
+static void guest_code(void)
+{
+ /* Create a pending interrupt on current vCPU */
+ x2apic_enable();
+ x2apic_write_reg(APIC_ICR, APIC_DEST_SELF | APIC_INT_ASSERT |
+ APIC_DM_FIXED | IRQ_VECTOR);
+
+ /*
+ * 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
+ *
+ * Enable interrupts during the single stepping to see that pending
+ * interrupt we raised is not handled due to KVM_GUESTDBG_BLOCKIRQ.
+ *
+ * Write MSR_IA32_TSC_DEADLINE to verify that KVM's fastpath handler
+ * exits to userspace due to single-step being enabled.
+ */
+ asm volatile("ss_start: "
+ "sti\n\t"
+ "xor %%eax,%%eax\n\t"
+ "cpuid\n\t"
+ "movl $" __stringify(MSR_IA32_TSC_DEADLINE) ", %%ecx\n\t"
+ "wrmsr\n\t"
+ "cli\n\t"
+ : : : "eax", "ebx", "ecx", "edx");
+
+ /* DR6.BD test */
+ asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
+ GUEST_DONE();
+}
+
+#define CAST_TO_RIP(v) ((unsigned long long)&(v))
+
+static void vcpu_skip_insn(struct kvm_vcpu *vcpu, int insn_len)
+{
+ struct kvm_regs regs;
+
+ vcpu_regs_get(vcpu, &regs);
+ regs.rip += insn_len;
+ vcpu_regs_set(vcpu, &regs);
+}
+
+int main(void)
+{
+ struct kvm_guest_debug debug;
+ unsigned long long target_dr6, target_rip;
+ struct kvm_vcpu *vcpu;
+ 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[6] = {
+ 1, /* sti*/
+ 2, /* xor */
+ 2, /* cpuid */
+ 5, /* mov */
+ 2, /* rdmsr */
+ 1, /* cli */
+ };
+
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG));
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ run = vcpu->run;
+
+ /* Test software BPs - int3 */
+ memset(&debug, 0, sizeof(debug));
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
+ vcpu_guest_debug_set(vcpu, &debug);
+ vcpu_run(vcpu);
+ 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));
+ vcpu_skip_insn(vcpu, 1);
+
+ /* Test instruction HW BP over DR[0-3] */
+ for (i = 0; i < 4; i++) {
+ memset(&debug, 0, sizeof(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));
+ vcpu_guest_debug_set(vcpu, &debug);
+ vcpu_run(vcpu);
+ 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" */
+ vcpu_skip_insn(vcpu, 1);
+
+ /* Test data access HW BP over DR[0-3] */
+ for (i = 0; i < 4; i++) {
+ memset(&debug, 0, sizeof(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));
+ vcpu_guest_debug_set(vcpu, &debug);
+ vcpu_run(vcpu);
+ 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" */
+ vcpu_skip_insn(vcpu, -7);
+ }
+ /* Skip the 4-bytes "mov" */
+ vcpu_skip_insn(vcpu, 7);
+
+ /* Test single step */
+ target_rip = CAST_TO_RIP(ss_start);
+ target_dr6 = 0xffff4ff0ULL;
+ for (i = 0; i < ARRAY_SIZE(ss_size); i++) {
+ target_rip += ss_size[i];
+ memset(&debug, 0, sizeof(debug));
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP |
+ KVM_GUESTDBG_BLOCKIRQ;
+ debug.arch.debugreg[7] = 0x00000400;
+ vcpu_guest_debug_set(vcpu, &debug);
+ vcpu_run(vcpu);
+ 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);
+ }
+
+ /* Finally test global disable */
+ memset(&debug, 0, sizeof(debug));
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
+ debug.arch.debugreg[7] = 0x400 | DR7_GD;
+ vcpu_guest_debug_set(vcpu, &debug);
+ vcpu_run(vcpu);
+ 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 */
+ memset(&debug, 0, sizeof(debug));
+ vcpu_guest_debug_set(vcpu, &debug);
+
+ vcpu_run(vcpu);
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+ cmd = get_ucall(vcpu, &uc);
+ TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE");
+
+ kvm_vm_free(vm);
+
+ return 0;
+}