KVM: arm64: Refactor __load_guest_stage2()

Refactor __load_guest_stage2() to introduce __load_stage2() which will
be re-used when loading the host stage 2.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-24-qperret@google.com

arch/arm64/include/asm/kvm_mmu.h

@@ -270,9 +270,9 @@ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu)
  * Must be called from hyp code running at EL2 with an updated VTTBR
  * and interrupts disabled.
  */
-static __always_inline void __load_guest_stage2(struct kvm_s2_mmu *mmu)
+static __always_inline void __load_stage2(struct kvm_s2_mmu *mmu, unsigned long vtcr)
 {
-	write_sysreg(kern_hyp_va(mmu->arch)->vtcr, vtcr_el2);
+	write_sysreg(vtcr, vtcr_el2);
 	write_sysreg(kvm_get_vttbr(mmu), vttbr_el2);
 
 	/*
@@ -283,6 +283,11 @@ static __always_inline void __load_guest_stage2(struct kvm_s2_mmu *mmu)
 	asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT));
 }
 
+static __always_inline void __load_guest_stage2(struct kvm_s2_mmu *mmu)
+{
+	__load_stage2(mmu, kern_hyp_va(mmu->arch)->vtcr);
+}
+
 static inline struct kvm *kvm_s2_mmu_to_kvm(struct kvm_s2_mmu *mmu)
 {
 	return container_of(mmu->arch, struct kvm, arch);