KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context

When running a guest hypervisor, ZCR_EL2 is an alias for the counterpart
EL1 state.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-6-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/kvm/fpsimd.c

@@ -178,7 +178,13 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 
 	if (guest_owns_fp_regs()) {
 		if (vcpu_has_sve(vcpu)) {
-			__vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
+			u64 zcr = read_sysreg_el1(SYS_ZCR);
+
+			/*
+			 * If the vCPU is in the hyp context then ZCR_EL1 is
+			 * loaded with its vEL2 counterpart.
+			 */
+			__vcpu_sys_reg(vcpu, vcpu_sve_zcr_elx(vcpu)) = zcr;
 
 			/*
 			 * Restore the VL that was saved when bound to the CPU,