KVM: arm64: Make RVBAR_EL2 accesses UNDEF

We always expose a virtual CPU that has EL3 when NV is enabled,
irrespective of EL3 being actually implemented in HW.

Therefore, as per the architecture, RVBAR_EL2 must UNDEF, since
EL2 is not the highest implemented exception level. This is
consistent with RMR_EL2 also triggering an UNDEF.

Adjust the handling of RVBAR_EL2 accordingly.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250714122634.3334816-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Marc Zyngier

arch/arm64/kvm/sys_regs.c

@@ -108,7 +108,6 @@ static bool get_el2_to_el1_mapping(unsigned int reg,
 		PURE_EL2_SYSREG(  HACR_EL2	);
 		PURE_EL2_SYSREG(  VTTBR_EL2	);
 		PURE_EL2_SYSREG(  VTCR_EL2	);
-		PURE_EL2_SYSREG(  RVBAR_EL2	);
 		PURE_EL2_SYSREG(  TPIDR_EL2	);
 		PURE_EL2_SYSREG(  HPFAR_EL2	);
 		PURE_EL2_SYSREG(  HCRX_EL2	);
@@ -3370,7 +3369,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_MPAMVPM7_EL2), undef_access },
 
 	EL2_REG(VBAR_EL2, access_rw, reset_val, 0),
-	EL2_REG(RVBAR_EL2, access_rw, reset_val, 0),
+	{ SYS_DESC(SYS_RVBAR_EL2), undef_access },
 	{ SYS_DESC(SYS_RMR_EL2), undef_access },
 
 	EL2_REG_VNCR(ICH_AP0R0_EL2, reset_val, 0),