KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2

The pkvm hypervisor at EL2 may need to read the 'kvm_vgic_global_state'
variable from the host, for example when saving and restoring the state
of the virtual GIC.

Explicitly map 'kvm_vgic_global_state' in the stage-1 page-table of the
pKVM hypervisor rather than relying on mapping all of the host '.rodata'
section.

Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-24-will@kernel.org

arch/arm64/kvm/hyp/nvhe/setup.c

@@ -161,6 +161,11 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
 	if (ret)
 		return ret;
 
+	ret = pkvm_create_mappings(&kvm_vgic_global_state,
+				   &kvm_vgic_global_state + 1, prot);
+	if (ret)
+		return ret;
+
 	return 0;
 }