From: Marc Zyngier <maz@kernel.org>

Simplify the early exception handling by slicing the gigantic decoding
tree into a more manageable set of functions, similar to what we have
in handle_exit.c.

This will also make the structure reusable for pKVM's own early exit
handling.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <redacted>
---
 arch/arm64/kvm/hyp/include/hyp/switch.h | 160 ++++++++++++++----------
 arch/arm64/kvm/hyp/nvhe/switch.c        |  17 +++
 arch/arm64/kvm/hyp/vhe/switch.c         |  17 +++
 3 files changed, 126 insertions(+), 68 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 54abc8298ec3..0397606c0951 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h

@@ -136,16 +136,7 @@ static inline void ___deactivate_traps(struct kvm_vcpu *vcpu)
 
 static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
 {
-	u8 ec;
-	u64 esr;
-
-	esr = vcpu->arch.fault.esr_el2;
-	ec = ESR_ELx_EC(esr);
-
-	if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
-		return true;
-
-	return __get_fault_info(esr, &vcpu->arch.fault);
+	return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault);
 }
 
 static inline void __hyp_sve_save_host(struct kvm_vcpu *vcpu)

@@ -166,8 +157,13 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
 	write_sysreg_el1(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR);
 }
 
-/* Check for an FPSIMD/SVE trap and handle as appropriate */
-static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu)
+/*
+ * We trap the first access to the FP/SIMD to save the host context and
+ * restore the guest context lazily.
+ * If FP/SIMD is not implemented, handle the trap and inject an undefined
+ * instruction exception to the guest. Similarly for trapped SVE accesses.
+ */
+static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	bool sve_guest, sve_host;
 	u8 esr_ec;

@@ -185,9 +181,6 @@ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu)
 	}
 
 	esr_ec = kvm_vcpu_trap_get_class(vcpu);
-	if (esr_ec != ESR_ELx_EC_FP_ASIMD &&
-	    esr_ec != ESR_ELx_EC_SVE)
-		return false;
 
 	/* Don't handle SVE traps for non-SVE vcpus here: */
 	if (!sve_guest && esr_ec != ESR_ELx_EC_FP_ASIMD)

@@ -325,7 +318,7 @@ static inline bool esr_is_ptrauth_trap(u32 esr)
 
 DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
 
-static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
+static bool kvm_hyp_handle_ptrauth(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	struct kvm_cpu_context *ctxt;
 	u64 val;

@@ -350,6 +343,87 @@ static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
 	return true;
 }
 
+static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+	if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) &&
+	    handle_tx2_tvm(vcpu))
+		return true;
+
+	if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
+	    __vgic_v3_perform_cpuif_access(vcpu) == 1)
+		return true;
+
+	return false;
+}
+
+static bool kvm_hyp_handle_cp15(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+	if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
+	    __vgic_v3_perform_cpuif_access(vcpu) == 1)
+		return true;