KVM: arm64: Don't advertise ICH_*_EL2 registers through GET_ONE_REG

It appears that exposing the GICv3 EL2 registers through the usual
sysreg interface is not consistent with the way we expose the EL1
registers. The latter are exposed via the GICv3 device interface
instead, and there is no reason why the EL2 registers should get
a different treatement.

Hide the registers from userspace until the GICv3 code grows the
required infrastructure.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250714122634.3334816-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Marc Zyngier

arch/arm64/kvm/sys_regs.c

@@ -772,6 +772,12 @@ static u64 reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	return mpidr;
 }
 
+static unsigned int hidden_visibility(const struct kvm_vcpu *vcpu,
+				      const struct sys_reg_desc *r)
+{
+	return REG_HIDDEN;
+}
+
 static unsigned int pmu_visibility(const struct kvm_vcpu *vcpu,
 				   const struct sys_reg_desc *r)
 {
@@ -2324,6 +2330,10 @@ static bool bad_redir_trap(struct kvm_vcpu *vcpu,
 	EL2_REG_FILTERED(name, acc, rst, v, el2_visibility)
 
 #define EL2_REG_VNCR(name, rst, v)	EL2_REG(name, bad_vncr_trap, rst, v)
+#define EL2_REG_VNCR_FILT(name, vis)			\
+	EL2_REG_FILTERED(name, bad_vncr_trap, reset_val, 0, vis)
+#define EL2_REG_VNCR_GICv3(name)			\
+	EL2_REG_VNCR_FILT(name, hidden_visibility)
 #define EL2_REG_REDIR(name, rst, v)	EL2_REG(name, bad_redir_trap, rst, v)
 
 /*
@@ -3372,40 +3382,40 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_RVBAR_EL2), undef_access },
 	{ SYS_DESC(SYS_RMR_EL2), undef_access },
 
-	EL2_REG_VNCR(ICH_AP0R0_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP0R1_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP0R2_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP0R3_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP1R0_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP1R1_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP1R2_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_AP1R3_EL2, reset_val, 0),
+	EL2_REG_VNCR_GICv3(ICH_AP0R0_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP0R1_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP0R2_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP0R3_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP1R0_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP1R1_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP1R2_EL2),
+	EL2_REG_VNCR_GICv3(ICH_AP1R3_EL2),
 
 	{ SYS_DESC(SYS_ICC_SRE_EL2), access_gic_sre },
 
-	EL2_REG_VNCR(ICH_HCR_EL2, reset_val, 0),
+	EL2_REG_VNCR_GICv3(ICH_HCR_EL2),
 	{ SYS_DESC(SYS_ICH_VTR_EL2), access_gic_vtr },
 	{ SYS_DESC(SYS_ICH_MISR_EL2), access_gic_misr },
 	{ SYS_DESC(SYS_ICH_EISR_EL2), access_gic_eisr },
 	{ SYS_DESC(SYS_ICH_ELRSR_EL2), access_gic_elrsr },
-	EL2_REG_VNCR(ICH_VMCR_EL2, reset_val, 0),
-
-	EL2_REG_VNCR(ICH_LR0_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR1_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR2_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR3_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR4_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR5_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR6_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR7_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR8_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR9_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR10_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR11_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR12_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR13_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR14_EL2, reset_val, 0),
-	EL2_REG_VNCR(ICH_LR15_EL2, reset_val, 0),
+	EL2_REG_VNCR_GICv3(ICH_VMCR_EL2),
+
+	EL2_REG_VNCR_GICv3(ICH_LR0_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR1_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR2_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR3_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR4_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR5_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR6_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR7_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR8_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR9_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR10_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR11_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR12_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR13_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR14_EL2),
+	EL2_REG_VNCR_GICv3(ICH_LR15_EL2),
 
 	EL2_REG(CONTEXTIDR_EL2, access_rw, reset_val, 0),
 	EL2_REG(TPIDR_EL2, access_rw, reset_val, 0),