[PATCH v3 28/66] KVM: arm64: nv: Forward debug traps to the nested guest

[Marc Zyngier]

On handling a debug trap, check whether we need to forward it to the
guest before handling it.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/include/asm/kvm_nested.h | 2 ++
 arch/arm64/kvm/emulate-nested.c     | 9 +++++++--
 arch/arm64/kvm/sys_regs.c           | 3 +++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 26cba7b4d743..07c15f51cf86 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -62,6 +62,8 @@ static inline u64 translate_cnthctl_el2_to_cntkctl_el1(u64 cnthctl)
 }
 
 int handle_wfx_nested(struct kvm_vcpu *vcpu, bool is_wfe);
+extern bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg,
+			    u64 control_bit);
 extern bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit);
 extern bool forward_nv_traps(struct kvm_vcpu *vcpu);
 
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index feb9b5eded96..df4661515183 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -25,14 +25,14 @@
 
 #include "trace.h"
 
-bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
+bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg, u64 control_bit)
 {
 	bool control_bit_set;
 
 	if (!nested_virt_in_use(vcpu))
 		return false;
 
-	control_bit_set = __vcpu_sys_reg(vcpu, HCR_EL2) & control_bit;
+	control_bit_set = __vcpu_sys_reg(vcpu, reg) & control_bit;
 	if (!vcpu_mode_el2(vcpu) && control_bit_set) {
 		kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
 		return true;
@@ -40,6 +40,11 @@ bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
 	return false;
 }
 
+bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
+{
+	return __forward_traps(vcpu, HCR_EL2, control_bit);
+}
+
 bool forward_nv_traps(struct kvm_vcpu *vcpu)
 {
 	return forward_traps(vcpu, HCR_NV);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index dc8a33ebad5f..80cf0c0761b9 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -607,6 +607,9 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
 			    struct sys_reg_params *p,
 			    const struct sys_reg_desc *r)
 {
+	if (__forward_traps(vcpu, MDCR_EL2, MDCR_EL2_TDA | MDCR_EL2_TDE))
+		return false;
+
 	access_rw(vcpu, p, r);
 	if (p->is_write)
 		vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
-- 
2.29.2