KVM: arm64: Unconditionally configure fine-grain traps

... otherwise we can inherit the host configuration if this differs from
the KVM configuration.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[maz: simplified a couple of things]
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: mrutland-arm

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

@@ -107,22 +107,19 @@ static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
 
 #define update_fgt_traps_cs(hctxt, vcpu, kvm, reg, clr, set)		\
 	do {								\
-		u64 c = 0, s = 0;					\
+		u64 c = clr, s = set;					\
+		u64 val;						\
 									\
 		ctxt_sys_reg(hctxt, reg) = read_sysreg_s(SYS_ ## reg);	\
 		if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu))		\
 			compute_clr_set(vcpu, reg, c, s);		\
 									\
 		compute_undef_clr_set(vcpu, kvm, reg, c, s);		\
 									\
-		s |= set;						\
-		c |= clr;						\
-		if (c || s) {						\
-			u64 val = __ ## reg ## _nMASK;			\
-			val |= s;					\
-			val &= ~c;					\
-			write_sysreg_s(val, SYS_ ## reg);		\
-		}							\
+		val = __ ## reg ## _nMASK;				\
+		val |= s;						\
+		val &= ~c;						\
+		write_sysreg_s(val, SYS_ ## reg);			\
 	} while(0)
 
 #define update_fgt_traps(hctxt, vcpu, kvm, reg)		\
@@ -175,33 +172,27 @@ static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 		update_fgt_traps(hctxt, vcpu, kvm, HAFGRTR_EL2);
 }
 
-#define __deactivate_fgt(htcxt, vcpu, kvm, reg)				\
+#define __deactivate_fgt(htcxt, vcpu, reg)				\
 	do {								\
-		if ((vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) ||	\
-		    kvm->arch.fgu[reg_to_fgt_group_id(reg)])		\
-			write_sysreg_s(ctxt_sys_reg(hctxt, reg),	\
-				       SYS_ ## reg);			\
+		write_sysreg_s(ctxt_sys_reg(hctxt, reg),		\
+			       SYS_ ## reg);				\
 	} while(0)
 
 static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
-	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
 
 	if (!cpus_have_final_cap(ARM64_HAS_FGT))
 		return;
 
-	__deactivate_fgt(hctxt, vcpu, kvm, HFGRTR_EL2);
-	if (cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
-		write_sysreg_s(ctxt_sys_reg(hctxt, HFGWTR_EL2), SYS_HFGWTR_EL2);
-	else
-		__deactivate_fgt(hctxt, vcpu, kvm, HFGWTR_EL2);
-	__deactivate_fgt(hctxt, vcpu, kvm, HFGITR_EL2);
-	__deactivate_fgt(hctxt, vcpu, kvm, HDFGRTR_EL2);
-	__deactivate_fgt(hctxt, vcpu, kvm, HDFGWTR_EL2);
+	__deactivate_fgt(hctxt, vcpu, HFGRTR_EL2);
+	__deactivate_fgt(hctxt, vcpu, HFGWTR_EL2);
+	__deactivate_fgt(hctxt, vcpu, HFGITR_EL2);
+	__deactivate_fgt(hctxt, vcpu, HDFGRTR_EL2);
+	__deactivate_fgt(hctxt, vcpu, HDFGWTR_EL2);
 
 	if (cpu_has_amu())
-		__deactivate_fgt(hctxt, vcpu, kvm, HAFGRTR_EL2);
+		__deactivate_fgt(hctxt, vcpu, HAFGRTR_EL2);
 }
 
 static inline void  __activate_traps_mpam(struct kvm_vcpu *vcpu)