Sorry for the scrambled message. Here is the patch
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index dd4efe1..8643ee5 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -294,6 +294,7 @@ static u16 group2_table[] = {
/* EFLAGS bit definitions. */
#define EFLG_OF (1<<11)
#define EFLG_DF (1<<10)
+#define EFLG_TF (1<<8)
#define EFLG_SF (1<<7)
#define EFLG_ZF (1<<6)
#define EFLG_AF (1<<4)
@@ -1767,6 +1768,9 @@ writeback:
if (rc != 0)
goto done;
+ if (ctxt->eflags & EFLG_TF)
+ kvm_inject_db(ctxt->vcpu,0);
+
/* Commit shadow register state. */
memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
kvm_rip_write(ctxt->vcpu, c->eip);
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 02b88ec..2af18f7 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -56,6 +56,7 @@
#define KVM_PAGES_PER_HPAGE (KVM_HPAGE_SIZE / PAGE_SIZE)
#define DE_VECTOR 0
+#define DB_VECTOR 1
#define UD_VECTOR 6
#define NM_VECTOR 7
#define DF_VECTOR 8
@@ -663,6 +664,11 @@ static inline void kvm_inject_gp(struct kvm_vcpu *vcpu, u32 error_code)
kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
}
+static inline void kvm_inject_db(struct kvm_vcpu *vcpu, u32 error_code)
+{
+ kvm_queue_exception_e(vcpu, DB_VECTOR, error_code);
+}
+
#define ASM_VMX_VMCLEAR_RAX ".byte 0x66, 0x0f, 0xc7, 0x30"
#define ASM_VMX_VMLAUNCH ".byte 0x0f, 0x01, 0xc2"
#define ASM_VMX_VMRESUME ".byte 0x0f, 0x01, 0xc3"
