KVM: arm64: Macros for setting/clearing FGT bits

There's a lot of boilerplate code for setting and clearing FGT
bits when activating guest traps. Refactor it into macros. These
macros will also be used in future patch series.

No functional change intended.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231214100158.2305400-15-tabba@google.com

Author: Fuad Tabba

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

@@ -79,6 +79,27 @@ static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
 		clr |= ~hfg & __ ## reg ## _nMASK; 			\
 	} while(0)
 
+#define update_fgt_traps_cs(vcpu, reg, clr, set)			\
+	do {								\
+		struct kvm_cpu_context *hctxt =				\
+			&this_cpu_ptr(&kvm_host_data)->host_ctxt;	\
+		u64 c = 0, s = 0;					\
+									\
+		ctxt_sys_reg(hctxt, reg) = read_sysreg_s(SYS_ ## reg);	\
+		compute_clr_set(vcpu, reg, c, s);			\
+		s |= set;						\
+		c |= clr;						\
+		if (c || s) {						\
+			u64 val = __ ## reg ## _nMASK;			\
+			val |= s;					\
+			val &= ~c;					\
+			write_sysreg_s(val, SYS_ ## reg);		\
+		}							\
+	} while(0)
+
+#define update_fgt_traps(vcpu, reg)		\
+	update_fgt_traps_cs(vcpu, reg, 0, 0)
+
 /*
  * Validate the fine grain trap masks.
  * Check that the masks do not overlap and that all bits are accounted for.
@@ -154,48 +175,12 @@ static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 	if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu))
 		return;
 
-	ctxt_sys_reg(hctxt, HFGITR_EL2) = read_sysreg_s(SYS_HFGITR_EL2);
-
-	r_set = r_clr = 0;
-	compute_clr_set(vcpu, HFGITR_EL2, r_clr, r_set);
-	r_val = __HFGITR_EL2_nMASK;
-	r_val |= r_set;
-	r_val &= ~r_clr;
-
-	write_sysreg_s(r_val, SYS_HFGITR_EL2);
-
-	ctxt_sys_reg(hctxt, HDFGRTR_EL2) = read_sysreg_s(SYS_HDFGRTR_EL2);
-	ctxt_sys_reg(hctxt, HDFGWTR_EL2) = read_sysreg_s(SYS_HDFGWTR_EL2);
-
-	r_clr = r_set = w_clr = w_set = 0;
-
-	compute_clr_set(vcpu, HDFGRTR_EL2, r_clr, r_set);
-	compute_clr_set(vcpu, HDFGWTR_EL2, w_clr, w_set);
-
-	r_val = __HDFGRTR_EL2_nMASK;
-	r_val |= r_set;
-	r_val &= ~r_clr;
-
-	w_val = __HDFGWTR_EL2_nMASK;
-	w_val |= w_set;
-	w_val &= ~w_clr;
-
-	write_sysreg_s(r_val, SYS_HDFGRTR_EL2);
-	write_sysreg_s(w_val, SYS_HDFGWTR_EL2);
-
-       if (!cpu_has_amu())
-               return;
-
-	ctxt_sys_reg(hctxt, HAFGRTR_EL2) = read_sysreg_s(SYS_HAFGRTR_EL2);
-
-	r_clr = r_set = 0;
-	compute_clr_set(vcpu, HAFGRTR_EL2, r_clr, r_set);
-
-	r_val = __HAFGRTR_EL2_nMASK;
-	r_val |= r_set;
-	r_val &= ~r_clr;
+	update_fgt_traps(vcpu, HFGITR_EL2);
+	update_fgt_traps(vcpu, HDFGRTR_EL2);
+	update_fgt_traps(vcpu, HDFGWTR_EL2);
 
-	write_sysreg_s(r_val, SYS_HAFGRTR_EL2);
+	if (cpu_has_amu())
+		update_fgt_traps(vcpu, HAFGRTR_EL2);
 }
 
 static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
@@ -215,7 +200,7 @@ static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 	write_sysreg_s(ctxt_sys_reg(hctxt, HDFGRTR_EL2), SYS_HDFGRTR_EL2);
 	write_sysreg_s(ctxt_sys_reg(hctxt, HDFGWTR_EL2), SYS_HDFGWTR_EL2);
 
-	if (vcpu_has_amu())
+	if (cpu_has_amu())
 		write_sysreg_s(ctxt_sys_reg(hctxt, HAFGRTR_EL2), SYS_HAFGRTR_EL2);
 }