[PATCH 3/7] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl

[Alex Bennée]

This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
ioctl. Currently any operation flag will return EINVAL. Actual
functionality will be added with further patches.

Signed-off-by: Alex Bennée <alex.bennee at linaro.org>.

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 7610eaa..2c6386e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2570,7 +2570,7 @@ handled.
 4.87 KVM_SET_GUEST_DEBUG
 
 Capability: KVM_CAP_SET_GUEST_DEBUG
-Architectures: x86, s390, ppc
+Architectures: x86, s390, ppc, arm64
 Type: vcpu ioctl
 Parameters: struct kvm_guest_debug (in)
 Returns: 0 on success; -1 on error
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9e193c8..a0ff410 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -180,6 +180,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_PSCI:
 	case KVM_CAP_ARM_PSCI_0_2:
 	case KVM_CAP_READONLY_MEM:
+	case KVM_CAP_SET_GUEST_DEBUG:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
@@ -302,7 +303,34 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 					struct kvm_guest_debug *dbg)
 {
-	return -EINVAL;
+	/* If it's not enabled clear all flags */
+	if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
+		vcpu->guest_debug = 0;
+		return 0;
+	}
+
+	vcpu->guest_debug = dbg->control;
+	kvm_info("%s: guest_debug is 0x%lx\n", __func__, vcpu->guest_debug);
+
+	/* Single Step */
+	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
+		kvm_info("SS requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	/* Software Break Points */
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) {
+		kvm_info("SW BP support requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	/* Hardware assisted Break and Watch points */
+	if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+		kvm_info("HW BP support requested, not yet implemented\n");
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 
-- 
2.1.3