[PATCH 2/2] KVM : powerpc/booke: Allow debug interrupt injection to guest

[Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>]

This patch allow userspace to inject debug interrupt to guest.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>
---
 arch/powerpc/kvm/booke.c  | 31 +++++++++++++++++++++++++++++--
 arch/powerpc/kvm/e500mc.c | 10 +++++++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index bb25937..63ac38c 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -135,6 +135,11 @@ static void kvmppc_vcpu_sync_fpu(struct kvm_vcpu *vcpu)
 #endif
 }
 
+static int kvmppc_core_pending_debug(struct kvm_vcpu *vcpu)
+{
+	return test_bit(BOOKE_IRQPRIO_DEBUG, &vcpu->arch.pending_exceptions);
+}
+
 static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu)
 {
 	/* Synchronize guest's desire to get debug interrupts into shadow MSR */
@@ -143,8 +148,11 @@ static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu)
 	vcpu->arch.shadow_msr |= vcpu->arch.shared->msr & MSR_DE;
 #endif
 
-	/* Force enable debug interrupts when user space wants to debug */
-	if (vcpu->guest_debug) {
+	/*
+	 * Force enable debug interrupts when user space wants to debug
+	 * and there is no debug interrupt pending for guest to handle.
+	 */
+	if (vcpu->guest_debug && !kvmppc_core_pending_debug(vcpu)) {
 #ifdef CONFIG_KVM_BOOKE_HV
 		/*
 		 * Since there is no shadow MSR, sync MSR_DE into the guest
@@ -264,6 +272,16 @@ static void kvmppc_core_dequeue_watchdog(struct kvm_vcpu *vcpu)
 	clear_bit(BOOKE_IRQPRIO_WATCHDOG, &vcpu->arch.pending_exceptions);
 }
 
+static void kvmppc_core_queue_debug(struct kvm_vcpu *vcpu)
+{
+	kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_DEBUG);
+}
+
+static void kvmppc_core_dequeue_debug(struct kvm_vcpu *vcpu)
+{
+	clear_bit(BOOKE_IRQPRIO_DEBUG, &vcpu->arch.pending_exceptions);
+}
+
 static void set_guest_srr(struct kvm_vcpu *vcpu, unsigned long srr0, u32 srr1)
 {
 #ifdef CONFIG_KVM_BOOKE_HV
@@ -1332,6 +1350,7 @@ static void get_sregs_base(struct kvm_vcpu *vcpu,
 	sregs->u.e.dec = kvmppc_get_dec(vcpu, tb);
 	sregs->u.e.tb = tb;
 	sregs->u.e.vrsave = vcpu->arch.vrsave;
+	sregs->u.e.dbsr = vcpu->arch.dbsr;
 }
 
 static int set_sregs_base(struct kvm_vcpu *vcpu,
@@ -1356,6 +1375,14 @@ static int set_sregs_base(struct kvm_vcpu *vcpu,
 	if (sregs->u.e.update_special & KVM_SREGS_E_UPDATE_TSR)
 		kvmppc_set_tsr(vcpu, sregs->u.e.tsr);
 
+	if (sregs->u.e.update_special & KVM_SREGS_E_UPDATE_DBSR) {
+		vcpu->arch.dbsr = sregs->u.e.dbsr;
+		if (vcpu->arch.dbsr)
+			kvmppc_core_queue_debug(vcpu);
+		else
+			kvmppc_core_dequeue_debug(vcpu);
+	}
+
 	return 0;
 }
 
diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index 17e4562..ea724f2 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -212,7 +212,7 @@ static int kvmppc_core_get_sregs_e500mc(struct kvm_vcpu *vcpu,
 	struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
 
 	sregs->u.e.features |= KVM_SREGS_E_ARCH206_MMU | KVM_SREGS_E_PM |
-			       KVM_SREGS_E_PC;
+			       KVM_SREGS_E_PC | KVM_SREGS_E_ED;
 	sregs->u.e.impl_id = KVM_SREGS_E_IMPL_FSL;
 
 	sregs->u.e.impl.fsl.features = 0;
@@ -220,6 +220,9 @@ static int kvmppc_core_get_sregs_e500mc(struct kvm_vcpu *vcpu,
 	sregs->u.e.impl.fsl.hid0 = vcpu_e500->hid0;
 	sregs->u.e.impl.fsl.mcar = vcpu_e500->mcar;
 
+	sregs->u.e.dsrr0 = vcpu->arch.dsrr0;
+	sregs->u.e.dsrr1 = vcpu->arch.dsrr1;
+
 	kvmppc_get_sregs_e500_tlb(vcpu, sregs);
 
 	sregs->u.e.ivor_high[3] =
@@ -261,6 +264,11 @@ static int kvmppc_core_set_sregs_e500mc(struct kvm_vcpu *vcpu,
 			sregs->u.e.ivor_high[5];
 	}
 
+	if (sregs->u.e.features & KVM_SREGS_E_ED) {
+		vcpu->arch.dsrr0 = sregs->u.e.dsrr0;
+		vcpu->arch.dsrr1 = sregs->u.e.dsrr1;
+	}
+
 	return kvmppc_set_sregs_ivor(vcpu, sregs);
 }
 
-- 
1.9.0

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