diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index bf0fe99e8ca9..018760675b56 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -270,6 +270,16 @@ static inline void __kvm_flush_dcache_pud(pud_t pud)
 void kvm_set_way_flush(struct kvm_vcpu *vcpu);
 void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);
 
+static inline bool __kvm_cpu_uses_extended_idmap(void)
+{
+	return false;
+}
+
+static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
+				       pgd_t *hyp_pgd,
+				       pgd_t *merged_hyp_pgd,
+				       unsigned long hyp_idmap_start) { }
+
 #endif	/* !__ASSEMBLY__ */
 
 #endif /* __ARM_KVM_MMU_H__ */
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 42a24d6b003b..69c2b4ce6160 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -35,6 +35,7 @@ extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];
 
 static pgd_t *boot_hyp_pgd;
 static pgd_t *hyp_pgd;
+static pgd_t *merged_hyp_pgd;
 static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
 
 static unsigned long hyp_idmap_start;
@@ -434,6 +435,11 @@ void free_hyp_pgds(void)
 		free_pages((unsigned long)hyp_pgd, hyp_pgd_order);
 		hyp_pgd = NULL;
 	}
+	if (merged_hyp_pgd) {
+		clear_page(merged_hyp_pgd);
+		free_page((unsigned long)merged_hyp_pgd);
+		merged_hyp_pgd = NULL;
+	}
 
 	mutex_unlock(&kvm_hyp_pgd_mutex);
 }
@@ -1473,12 +1479,18 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 
 phys_addr_t kvm_mmu_get_httbr(void)
 {
-	return virt_to_phys(hyp_pgd);
+	if (__kvm_cpu_uses_extended_idmap())
+		return virt_to_phys(merged_hyp_pgd);
+	else
+		return virt_to_phys(hyp_pgd);
 }
 
 phys_addr_t kvm_mmu_get_boot_httbr(void)
 {
-	return virt_to_phys(boot_hyp_pgd);
+	if (__kvm_cpu_uses_extended_idmap())
+		return virt_to_phys(merged_hyp_pgd);
+	else
+		return virt_to_phys(boot_hyp_pgd);
 }
 
 phys_addr_t kvm_get_idmap_vector(void)
@@ -1521,6 +1533,17 @@ int kvm_mmu_init(void)
 		goto out;
 	}
 
+	if (__kvm_cpu_uses_extended_idmap()) {
+		merged_hyp_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+		if (!merged_hyp_pgd) {
+			kvm_err("Failed to allocate extra HYP pgd\n");
+			goto out;
+		}
+		__kvm_extend_hypmap(boot_hyp_pgd, hyp_pgd, merged_hyp_pgd,
+				    hyp_idmap_start);
+		return 0;
+	}
+
 	/* Map the very same page at the trampoline VA */
 	err = 	__create_hyp_mappings(boot_hyp_pgd,
 				      TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE,
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 6458b5373142..edfe6864bc28 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -68,6 +68,8 @@
 #include <asm/pgalloc.h>
 #include <asm/cachetype.h>
 #include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
 
 #define KERN_TO_HYP(kva)	((unsigned long)kva - PAGE_OFFSET + HYP_PAGE_OFFSET)
 
@@ -305,5 +307,36 @@ static inline void __kvm_flush_dcache_pud(pud_t pud)
 void kvm_set_way_flush(struct kvm_vcpu *vcpu);
 void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);
 
+static inline bool __kvm_cpu_uses_extended_idmap(void)
+{
+	return __cpu_uses_extended_idmap();
+}
+
+static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
+				       pgd_t *hyp_pgd,
+				       pgd_t *merged_hyp_pgd,
+				       unsigned long hyp_idmap_start)
+{
+	int idmap_idx;
+
+	/*
+	 * Use the first entry to access the HYP mappings. It is
+	 * guaranteed to be free, otherwise we wouldn't use an
+	 * extended idmap.
+	 */
+	VM_BUG_ON(pgd_val(merged_hyp_pgd[0]));
+	merged_hyp_pgd[0] = __pgd(__pa(hyp_pgd) | PMD_TYPE_TABLE);
+
+	/*
+	 * Create another extended level entry that points to the boot HYP map,
+	 * which contains an ID mapping of the HYP init code. We essentially
+	 * merge the boot and runtime HYP maps by doing so, but they don't
+	 * overlap anyway, so this is fine.
+	 */
+	idmap_idx = hyp_idmap_start >> VA_BITS;
+	VM_BUG_ON(pgd_val(merged_hyp_pgd[idmap_idx]));
+	merged_hyp_pgd[idmap_idx] = __pgd(__pa(boot_hyp_pgd) | PMD_TYPE_TABLE);
+}
+
 #endif /* __ASSEMBLY__ */
 #endif /* __ARM64_KVM_MMU_H__ */
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index c3191168a994..178ba2248a98 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -20,6 +20,7 @@
 #include <asm/assembler.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
+#include <asm/pgtable-hwdef.h>
 
 	.text
 	.pushsection	.hyp.idmap.text, "ax"
@@ -65,6 +66,25 @@ __do_hyp_init:
 	and	x4, x4, x5
 	ldr	x5, =TCR_EL2_FLAGS
 	orr	x4, x4, x5
+
+#ifndef CONFIG_ARM64_VA_BITS_48
+	/*
+	 * If we are running with VA_BITS < 48, we may be running with an extra
+	 * level of translation in the ID map. This is only the case if system
+	 * RAM is out of range for the currently configured page size and number
+	 * of translation levels, in which case we will also need the extra
+	 * level for the HYP ID map, or we won't be able to enable the EL2 MMU.
+	 *
+	 * However, at EL2, there is only one TTBR register, and we can't switch
+	 * between translation tables *and* update TCR_EL2.T0SZ at the same
+	 * time. Bottom line: we need the extra level in *both* our translation
+	 * tables.
+	 *
+	 * So use the same T0SZ value we use for the ID map.
+	 */
+	ldr_l	x5, idmap_t0sz
+	bfi	x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
+#endif
 	msr	tcr_el2, x4
 
 	ldr	x4, =VTCR_EL2_FLAGS
@@ -91,6 +111,10 @@ __do_hyp_init:
 	msr	sctlr_el2, x4
 	isb
 
+	/* Skip the trampoline dance if we merged the boot and runtime PGDs */
+	cmp	x0, x1
+	b.eq	merged
+
 	/* MMU is now enabled. Get ready for the trampoline dance */
 	ldr	x4, =TRAMPOLINE_VA
 	adr	x5, target
@@ -105,6 +129,7 @@ target: /* We're now in the trampoline code, switch page tables */
 	tlbi	alle2
 	dsb	sy
 
+merged:
 	/* Set the stack and new vectors */
 	kern_hyp_va	x2
 	mov	sp, x2