KVM: arm64: Exclude mdcr_el2_host from kvm_vcpu_arch

As for the rest of the host debug state, the host copy of mdcr_el2
has little to do in the vcpu, and is better placed in the host_data
structure.

Reviewed-by : Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/kvm_host.h

@@ -555,6 +555,8 @@ struct kvm_host_data {
 		u64 pmscr_el1;
 		/* Self-hosted trace */
 		u64 trfcr_el1;
+		/* Values of trap registers for the host before guest entry. */
+		u64 mdcr_el2;
 	} host_debug_state;
 };
 
@@ -616,9 +618,6 @@ struct kvm_vcpu_arch {
 	u64 mdcr_el2;
 	u64 cptr_el2;
 
-	/* Values of trap registers for the host before guest entry. */
-	u64 mdcr_el2_host;
-
 	/* Exception Information */
 	struct kvm_vcpu_fault_info fault;
 

arch/arm64/kvm/hyp/include/hyp/switch.h

@@ -232,7 +232,7 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
 		vcpu_set_flag(vcpu, PMUSERENR_ON_CPU);
 	}
 
-	vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2);
+	*host_data_ptr(host_debug_state.mdcr_el2) = read_sysreg(mdcr_el2);
 	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
 
 	if (cpus_have_final_cap(ARM64_HAS_HCX)) {
@@ -254,7 +254,7 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
 
 static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
 {
-	write_sysreg(vcpu->arch.mdcr_el2_host, mdcr_el2);
+	write_sysreg(*host_data_ptr(host_debug_state.mdcr_el2), mdcr_el2);
 
 	write_sysreg(0, hstr_el2);
 	if (kvm_arm_support_pmu_v3()) {