[PATCH 11/11] KVM-x86: Wire up host-managed debug registers

[Jan Kiszka <jan.kiszka@web.de>]

Add the remaining bits to make use of debug registers also for guest
debugging, thus enabling the use of hardware breakpoints and
watchpoints.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
 arch/x86/kvm/svm.c |    5 +++++
 arch/x86/kvm/vmx.c |    5 +++++
 arch/x86/kvm/x86.c |   14 +++++++++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

Index: b/arch/x86/kvm/svm.c
===================================================================
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -889,6 +889,11 @@ static int svm_guest_debug(struct kvm_vc
 	} else
 		vcpu->guest_debug = 0;
 
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+		svm->vmcb->save.dr7 = dbg->arch.debugreg[7];
+	else
+		svm->vmcb->save.dr7 = vcpu->arch.dr7;
+
 	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
 		svm->vmcb->save.rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
 	else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -964,6 +964,11 @@ static int set_guest_debug(struct kvm_vc
 	if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
 		vcpu->guest_debug = 0;
 
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+		vmcs_writel(GUEST_DR7, dbg->arch.debugreg[7]);
+	else
+		vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+
 	flags = vmcs_readl(GUEST_RFLAGS);
 	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
 		flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
Index: b/arch/x86/kvm/x86.c
===================================================================
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3612,10 +3612,22 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 					struct kvm_guest_debug *dbg)
 {
-	int r;
+	int i, r;
 
 	vcpu_load(vcpu);
 
+	if ((dbg->control & (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) ==
+	    (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) {
+		for (i = 0; i < KVM_NR_DB_REGS; ++i)
+			vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
+		vcpu->arch.switch_db_regs =
+			(dbg->arch.debugreg[7] & DR7_BP_EN_MASK);
+	} else {
+		for (i = 0; i < KVM_NR_DB_REGS; i++)
+			vcpu->arch.eff_db[i] = vcpu->arch.db[i];
+		vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK);
+	}
+
 	r = kvm_x86_ops->set_guest_debug(vcpu, dbg);
 
 	if (dbg->control & KVM_GUESTDBG_INJECT_DB)