[6/6] KVM: x86: Emulator support for TF

Commit Message

Jan Kiszka Feb. 22, 2010, 5:51 p.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d46e791..d69d8aa 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -362,8 +362,11 @@  struct kvm_vcpu_arch {
 	u64 *mce_banks;
 
 	/* used for guest single stepping over the given code position */
+	bool singlestep_pending;
 	u16 singlestep_cs;
+	u16 singlestep_pending_cs;
 	unsigned long singlestep_rip;
+	unsigned long singlestep_pending_rip;
 	/* fields used by HYPER-V emulation */
 	u64 hv_vapic;
 };
@@ -820,4 +823,6 @@  int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
 void kvm_define_shared_msr(unsigned index, u32 msr);
 void kvm_set_shared_msr(unsigned index, u64 val, u64 mask);
 
+int kvm_check_guest_singlestep(struct kvm_vcpu *vcpu);
+
 #endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d772476..317828f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3489,6 +3489,12 @@  static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 			goto out;
 		if (need_resched())
 			schedule();
+
+		if (unlikely(vcpu->arch.singlestep_pending)) {
+			ret = kvm_check_guest_singlestep(vcpu);
+			if (ret == 0)
+				goto out;
+		}
 	}
 
 	vmx->emulation_required = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 19e8b28..6ebebb9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3441,6 +3441,27 @@  static void cache_all_regs(struct kvm_vcpu *vcpu)
 	vcpu->arch.regs_dirty = ~0;
 }
 
+static u16 get_segment_selector(struct kvm_vcpu *vcpu, int seg)
+{
+	struct kvm_segment kvm_seg;
+
+	kvm_get_segment(vcpu, &kvm_seg, seg);
+	return kvm_seg.selector;
+}
+
+static void queue_singlestep(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
+		vcpu->arch.singlestep_pending = true;
+		vcpu->arch.singlestep_pending_cs =
+			get_segment_selector(vcpu, VCPU_SREG_CS);
+		vcpu->arch.singlestep_pending_rip = kvm_rip_read(vcpu);
+	} else {
+		vcpu->arch.dr6 |= DR6_BS;
+		kvm_queue_exception(vcpu, DB_VECTOR);
+	}
+}
+
 int emulate_instruction(struct kvm_vcpu *vcpu,
 			unsigned long cr2,
 			u16 error_code,
@@ -3449,6 +3470,7 @@  int emulate_instruction(struct kvm_vcpu *vcpu,
 	int r, shadow_mask;
 	struct decode_cache *c;
 	struct kvm_run *run = vcpu->run;
+	bool singlestep;
 
 	kvm_clear_exception_queue(vcpu);
 	vcpu->arch.mmio_fault_cr2 = cr2;
@@ -3515,8 +3537,12 @@  int emulate_instruction(struct kvm_vcpu *vcpu,
 		}
 	}
 
+	singlestep = vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_TF;
+
 	if (emulation_type & EMULTYPE_SKIP) {
 		kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.decode.eip);
+		if (singlestep)
+			queue_singlestep(vcpu);
 		return EMULATE_DONE;
 	}
 
@@ -3549,6 +3575,9 @@  int emulate_instruction(struct kvm_vcpu *vcpu,
 
 	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
 
+	if (singlestep)
+		queue_singlestep(vcpu);
+
 	if (vcpu->mmio_is_write) {
 		vcpu->mmio_needed = 0;
 		return EMULATE_DO_MMIO;
@@ -4450,6 +4479,26 @@  out:
 	return r;
 }
 
+int kvm_check_guest_singlestep(struct kvm_vcpu *vcpu)
+{
+	unsigned long rip = kvm_rip_read(vcpu);
+
+	vcpu->arch.singlestep_pending = false;
+
+	if (vcpu->arch.singlestep_pending_cs !=
+		get_segment_selector(vcpu, VCPU_SREG_CS) ||
+	    vcpu->arch.singlestep_pending_rip != rip)
+		return 1;
+
+	vcpu->run->debug.arch.dr6 = DR6_BS | DR6_FIXED_1;
+	vcpu->run->debug.arch.dr7 = 0;
+	vcpu->run->exit_reason = KVM_EXIT_DEBUG;
+	vcpu->run->debug.arch.pc = get_segment_base(vcpu, VCPU_SREG_CS) + rip;
+	vcpu->run->debug.arch.exception = DB_VECTOR;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_check_guest_singlestep);
 
 static int __vcpu_run(struct kvm_vcpu *vcpu)
 {
@@ -4471,6 +4520,12 @@  static int __vcpu_run(struct kvm_vcpu *vcpu)
 
 	r = 1;
 	while (r > 0) {
+		if (unlikely(vcpu->arch.singlestep_pending)) {
+			r = kvm_check_guest_singlestep(vcpu);
+			if (r == 0)
+				break;
+		}
+
 		if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
 			r = vcpu_enter_guest(vcpu);
 		else {
@@ -4828,14 +4883,6 @@  static gpa_t get_tss_base_addr_read(struct kvm_vcpu *vcpu,
 	return kvm_mmu_gva_to_gpa_read(vcpu, base_addr, NULL);
 }
 
-static u16 get_segment_selector(struct kvm_vcpu *vcpu, int seg)
-{
-	struct kvm_segment kvm_seg;
-
-	kvm_get_segment(vcpu, &kvm_seg, seg);
-	return kvm_seg.selector;
-}
-
 static int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg)
 {
 	struct kvm_segment segvar = {
@@ -5607,6 +5654,8 @@  int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
 	vcpu->arch.dr6 = DR6_FIXED_1;
 	vcpu->arch.dr7 = DR7_FIXED_1;
 
+	vcpu->arch.singlestep_pending = false;
+
 	return kvm_x86_ops->vcpu_reset(vcpu);
 }