[PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Mike Rapoport]

From: Mike Rapoport <rppt@linux.ibm.com>

Hi,

This is a part of clean up of the page table manipulation code that aims to
remove asm-generic/5level-fixup.h and asm-generic/pgtable-nop4d-hack.h

There is a single patch for both arm and arm64 because doing the conversion
separately would mean breaking the shared mmu bits in virt/kvm/arm.

v2:
* fix build error for arch/arm64/mm/dump.c
* simplify p4d unfolding in arch/arm64/mm/kasan_init.c

Mike Rapoport (1):
  arm/arm64: add support for folded p4d page tables

 arch/arm/include/asm/kvm_mmu.h          |   5 +-
 arch/arm/include/asm/pgtable.h          |   1 -
 arch/arm/include/asm/stage2_pgtable.h   |  15 +-
 arch/arm/lib/uaccess_with_memcpy.c      |   9 +-
 arch/arm/mach-sa1100/assabet.c          |   2 +-
 arch/arm/mm/dump.c                      |  29 +++-
 arch/arm/mm/fault-armv.c                |   7 +-
 arch/arm/mm/fault.c                     |  28 +++-
 arch/arm/mm/idmap.c                     |   3 +-
 arch/arm/mm/init.c                      |   2 +-
 arch/arm/mm/ioremap.c                   |  12 +-
 arch/arm/mm/mm.h                        |   2 +-
 arch/arm/mm/mmu.c                       |  35 +++-
 arch/arm/mm/pgd.c                       |  40 ++++-
 arch/arm64/include/asm/kvm_mmu.h        |  10 +-
 arch/arm64/include/asm/pgalloc.h        |  10 +-
 arch/arm64/include/asm/pgtable-types.h  |   5 +-
 arch/arm64/include/asm/pgtable.h        |  37 +++--
 arch/arm64/include/asm/stage2_pgtable.h |  48 ++++--
 arch/arm64/kernel/hibernate.c           |  46 +++++-
 arch/arm64/mm/dump.c                    |  29 +++-
 arch/arm64/mm/fault.c                   |   9 +-
 arch/arm64/mm/hugetlbpage.c             |  15 +-
 arch/arm64/mm/kasan_init.c              |  26 ++-
 arch/arm64/mm/mmu.c                     |  52 ++++--
 arch/arm64/mm/pageattr.c                |   7 +-
 virt/kvm/arm/mmu.c                      | 209 ++++++++++++++++++++----
 27 files changed, 550 insertions(+), 143 deletions(-)

-- 
2.24.0


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[PATCH v2 1/1] arm/arm64: add support for folded p4d page tables

[Mike Rapoport]

From: Mike Rapoport <rppt@linux.ibm.com>

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and
remove __ARCH_USE_5LEVEL_HACK.

Since arm and arm64 share kvm memory management bits, make the conversion
for both variants at once to avoid breaking the builds in the middle.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
 arch/arm/include/asm/kvm_mmu.h          |   5 +-
 arch/arm/include/asm/pgtable.h          |   1 -
 arch/arm/include/asm/stage2_pgtable.h   |  15 +-
 arch/arm/lib/uaccess_with_memcpy.c      |   9 +-
 arch/arm/mach-sa1100/assabet.c          |   2 +-
 arch/arm/mm/dump.c                      |  29 +++-
 arch/arm/mm/fault-armv.c                |   7 +-
 arch/arm/mm/fault.c                     |  28 +++-
 arch/arm/mm/idmap.c                     |   3 +-
 arch/arm/mm/init.c                      |   2 +-
 arch/arm/mm/ioremap.c                   |  12 +-
 arch/arm/mm/mm.h                        |   2 +-
 arch/arm/mm/mmu.c                       |  35 +++-
 arch/arm/mm/pgd.c                       |  40 ++++-
 arch/arm64/include/asm/kvm_mmu.h        |  10 +-
 arch/arm64/include/asm/pgalloc.h        |  10 +-
 arch/arm64/include/asm/pgtable-types.h  |   5 +-
 arch/arm64/include/asm/pgtable.h        |  37 +++--
 arch/arm64/include/asm/stage2_pgtable.h |  48 ++++--
 arch/arm64/kernel/hibernate.c           |  46 +++++-
 arch/arm64/mm/dump.c                    |  29 +++-
 arch/arm64/mm/fault.c                   |   9 +-
 arch/arm64/mm/hugetlbpage.c             |  15 +-
 arch/arm64/mm/kasan_init.c              |  26 ++-
 arch/arm64/mm/mmu.c                     |  52 ++++--
 arch/arm64/mm/pageattr.c                |   7 +-
 virt/kvm/arm/mmu.c                      | 209 ++++++++++++++++++++----
 27 files changed, 550 insertions(+), 143 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 0d84d50bf9ba..8c511bb99e4c 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -68,7 +68,8 @@ void kvm_clear_hyp_idmap(void);
 
 #define kvm_mk_pmd(ptep)	__pmd(__pa(ptep) | PMD_TYPE_TABLE)
 #define kvm_mk_pud(pmdp)	__pud(__pa(pmdp) | PMD_TYPE_TABLE)
-#define kvm_mk_pgd(pudp)	({ BUILD_BUG(); 0; })
+#define kvm_mk_p4d(pudp)	({ BUILD_BUG(); __p4d(0); })
+#define kvm_mk_pgd(p4dp)	({ BUILD_BUG(); 0; })
 
 #define kvm_pfn_pte(pfn, prot)	pfn_pte(pfn, prot)
 #define kvm_pfn_pmd(pfn, prot)	pfn_pmd(pfn, prot)
@@ -194,10 +195,12 @@ static inline bool kvm_page_empty(void *ptr)
 #define kvm_pte_table_empty(kvm, ptep) kvm_page_empty(ptep)
 #define kvm_pmd_table_empty(kvm, pmdp) kvm_page_empty(pmdp)
 #define kvm_pud_table_empty(kvm, pudp) false
+#define kvm_p4d_table_empty(kvm, p4dp) false
 
 #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
 #define hyp_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
 #define hyp_pud_table_empty(pudp) false
+#define hyp_p4d_table_empty(p4dp) false
 
 struct kvm;
 
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index eabcb48a7840..9e3464842dfc 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -17,7 +17,6 @@
 
 #else
 
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopud.h>
 #include <asm/memory.h>
 #include <asm/pgtable-hwdef.h>
diff --git a/arch/arm/include/asm/stage2_pgtable.h b/arch/arm/include/asm/stage2_pgtable.h
index aaceec7855ec..7ed66e216a5e 100644
--- a/arch/arm/include/asm/stage2_pgtable.h
+++ b/arch/arm/include/asm/stage2_pgtable.h
@@ -19,8 +19,17 @@
 #define stage2_pgd_none(kvm, pgd)		pgd_none(pgd)
 #define stage2_pgd_clear(kvm, pgd)		pgd_clear(pgd)
 #define stage2_pgd_present(kvm, pgd)		pgd_present(pgd)
-#define stage2_pgd_populate(kvm, pgd, pud)	pgd_populate(NULL, pgd, pud)
-#define stage2_pud_offset(kvm, pgd, address)	pud_offset(pgd, address)
+#define stage2_pgd_populate(kvm, pgd, p4d)	pgd_populate(NULL, pgd, p4d)
+
+#define stage2_p4d_offset(kvm, pgd, address)	p4d_offset(pgd, address)
+#define stage2_p4d_free(kvm, p4d)		do { } while (0)
+
+#define stage2_p4d_none(kvm, p4d)		p4d_none(p4d)
+#define stage2_p4d_clear(kvm, p4d)		p4d_clear(p4d)
+#define stage2_p4d_present(kvm, p4d)		p4d_present(p4d)
+#define stage2_p4d_populate(kvm, p4d, pud)	p4d_populate(NULL, p4d, pud)
+
+#define stage2_pud_offset(kvm, p4d, address)	pud_offset(p4d, address)
 #define stage2_pud_free(kvm, pud)		do { } while (0)
 
 #define stage2_pud_none(kvm, pud)		pud_none(pud)
@@ -41,6 +50,7 @@ stage2_pgd_addr_end(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
 	return (boundary - 1 < end - 1) ? boundary : end;
 }
 
+#define stage2_p4d_addr_end(kvm, addr, end)	(end)
 #define stage2_pud_addr_end(kvm, addr, end)	(end)
 
 static inline phys_addr_t
@@ -56,6 +66,7 @@ stage2_pmd_addr_end(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
 #define stage2_pte_table_empty(kvm, ptep)	kvm_page_empty(ptep)
 #define stage2_pmd_table_empty(kvm, pmdp)	kvm_page_empty(pmdp)
 #define stage2_pud_table_empty(kvm, pudp)	false
+#define stage2_p4d_table_empty(kvm, p4dp)	false
 
 static inline bool kvm_stage2_has_pud(struct kvm *kvm)
 {
diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index c9450982a155..cabf1119c256 100644
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -24,6 +24,7 @@ pin_page_for_write(const void __user *_addr, pte_t **ptep, spinlock_t **ptlp)
 {
 	unsigned long addr = (unsigned long)_addr;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pmd_t *pmd;
 	pte_t *pte;
 	pud_t *pud;
@@ -33,7 +34,11 @@ pin_page_for_write(const void __user *_addr, pte_t **ptep, spinlock_t **ptlp)
 	if (unlikely(pgd_none(*pgd) || pgd_bad(*pgd)))
 		return 0;
 
-	pud = pud_offset(pgd, addr);
+	p4d = p4d_offset(pgd, addr);
+	if (unlikely(p4d_none(*p4d) || p4d_bad(*p4d)))
+		return 0;
+
+	pud = pud_offset(p4d, addr);
 	if (unlikely(pud_none(*pud) || pud_bad(*pud)))
 		return 0;
 
@@ -154,7 +159,7 @@ arm_copy_to_user(void __user *to, const void *from, unsigned long n)
 	}
 	return n;
 }
-	
+
 static unsigned long noinline
 __clear_user_memset(void __user *addr, unsigned long n)
 {
diff --git a/arch/arm/mach-sa1100/assabet.c b/arch/arm/mach-sa1100/assabet.c
index d96a101e5504..0631a7b02678 100644
--- a/arch/arm/mach-sa1100/assabet.c
+++ b/arch/arm/mach-sa1100/assabet.c
@@ -633,7 +633,7 @@ static void __init map_sa1100_gpio_regs( void )
 	int prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_DOMAIN(DOMAIN_IO);
 	pmd_t *pmd;
 
-	pmd = pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);
+	pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(virt), virt), virt), virt);
 	*pmd = __pmd(phys | prot);
 	flush_pmd_entry(pmd);
 }
diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 7d6291f23251..677549d6854c 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -207,6 +207,7 @@ struct pg_level {
 static struct pg_level pg_level[] = {
 	{
 	}, { /* pgd */
+	}, { /* p4d */
 	}, { /* pud */
 	}, { /* pmd */
 		.bits	= section_bits,
@@ -308,7 +309,7 @@ static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
 
 	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 		addr = start + i * PAGE_SIZE;
-		note_page(st, addr, 4, pte_val(*pte), domain);
+		note_page(st, addr, 5, pte_val(*pte), domain);
 	}
 }
 
@@ -350,14 +351,14 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 			addr += SECTION_SIZE;
 			pmd++;
 			domain = get_domain_name(pmd);
-			note_page(st, addr, 3, pmd_val(*pmd), domain);
+			note_page(st, addr, 4, pmd_val(*pmd), domain);
 		}
 	}
 }
 
-static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
+static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
 {
-	pud_t *pud = pud_offset(pgd, 0);
+	pud_t *pud = pud_offset(p4d, 0);
 	unsigned long addr;
 	unsigned i;
 
@@ -366,7 +367,23 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 		if (!pud_none(*pud)) {
 			walk_pmd(st, pud, addr);
 		} else {
-			note_page(st, addr, 2, pud_val(*pud), NULL);
+			note_page(st, addr, 3, pud_val(*pud), NULL);
+		}
+	}
+}
+
+static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
+{
+	p4d_t *p4d = p4d_offset(pgd, 0);
+	unsigned long addr;
+	unsigned i;
+
+	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
+		addr = start + i * P4D_SIZE;
+		if (!p4d_none(*p4d)) {
+			walk_pud(st, p4d, addr);
+		} else {
+			note_page(st, addr, 2, p4d_val(*p4d), NULL);
 		}
 	}
 }
@@ -381,7 +398,7 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
 	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 		addr = start + i * PGDIR_SIZE;
 		if (!pgd_none(*pgd)) {
-			walk_pud(st, pgd, addr);
+			walk_p4d(st, pgd, addr);
 		} else {
 			note_page(st, addr, 1, pgd_val(*pgd), NULL);
 		}
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index ae857f41f68d..489aaafa6ebd 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -91,6 +91,7 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 {
 	spinlock_t *ptl;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
@@ -100,7 +101,11 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 	if (pgd_none_or_clear_bad(pgd))
 		return 0;
 
-	pud = pud_offset(pgd, address);
+	p4d = p4d_offset(pgd, address);
+	if (p4d_none_or_clear_bad(p4d))
+		return 0;
+
+	pud = pud_offset(p4d, address);
 	if (pud_none_or_clear_bad(pud))
 		return 0;
 
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index bd0f4821f7e1..c2bd35a822e3 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -43,6 +43,7 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr)
 	printk("%s[%08lx] *pgd=%08llx", lvl, addr, (long long)pgd_val(*pgd));
 
 	do {
+		p4d_t *p4d;
 		pud_t *pud;
 		pmd_t *pmd;
 		pte_t *pte;
@@ -55,7 +56,19 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr)
 			break;
 		}
 
-		pud = pud_offset(pgd, addr);
+		p4d = p4d_offset(pgd, addr);
+		if (PTRS_PER_P4D != 1)
+			pr_cont(", *p4d=%08llx", (long long)p4d_val(*p4d));
+
+		if (p4d_none(*p4d))
+			break;
+
+		if (p4d_bad(*p4d)) {
+			pr_cont("(bad)");
+			break;
+		}
+
+		pud = pud_offset(p4d, addr);
 		if (PTRS_PER_PUD != 1)
 			pr_cont(", *pud=%08llx", (long long)pud_val(*pud));
 
@@ -408,6 +421,7 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 {
 	unsigned int index;
 	pgd_t *pgd, *pgd_k;
+	p4d_t *p4d, *p4d_k;
 	pud_t *pud, *pud_k;
 	pmd_t *pmd, *pmd_k;
 
@@ -427,8 +441,16 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 	if (!pgd_present(*pgd))
 		set_pgd(pgd, *pgd_k);
 
-	pud = pud_offset(pgd, addr);
-	pud_k = pud_offset(pgd_k, addr);
+	p4d = p4d_offset(pgd, addr);
+	p4d_k = p4d_offset(pgd_k, addr);
+
+	if (p4d_none(*p4d_k))
+		goto bad_area;
+	if (!p4d_present(*p4d))
+		set_p4d(p4d, *p4d_k);
+
+	pud = pud_offset(p4d, addr);
+	pud_k = pud_offset(p4d_k, addr);
 
 	if (pud_none(*pud_k))
 		goto bad_area;
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index a033f6134a64..cd54411ef1b8 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -68,7 +68,8 @@ static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 	unsigned long prot)
 {
-	pud_t *pud = pud_offset(pgd, addr);
+	p4d_t *p4d = p4d_offset(pgd, addr);
+	pud_t *pud = pud_offset(p4d, addr);
 	unsigned long next;
 
 	do {
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 3ef204137e73..0b3803328735 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -571,7 +571,7 @@ static inline void section_update(unsigned long addr, pmdval_t mask,
 {
 	pmd_t *pmd;
 
-	pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+	pmd = pmd_off_k(addr);
 
 #ifdef CONFIG_ARM_LPAE
 	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 72286f9a4d30..75529d76d28c 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -142,12 +142,14 @@ static void unmap_area_sections(unsigned long virt, unsigned long size)
 {
 	unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmdp;
 
 	flush_cache_vunmap(addr, end);
 	pgd = pgd_offset_k(addr);
-	pud = pud_offset(pgd, addr);
+	p4d = p4d_offset(pgd, addr);
+	pud = pud_offset(p4d, addr);
 	pmdp = pmd_offset(pud, addr);
 	do {
 		pmd_t pmd = *pmdp;
@@ -190,6 +192,7 @@ remap_area_sections(unsigned long virt, unsigned long pfn,
 {
 	unsigned long addr = virt, end = virt + size;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 
@@ -200,7 +203,8 @@ remap_area_sections(unsigned long virt, unsigned long pfn,
 	unmap_area_sections(virt, size);
 
 	pgd = pgd_offset_k(addr);
-	pud = pud_offset(pgd, addr);
+	p4d = p4d_offset(pgd, addr);
+	pud = pud_offset(p4d, addr);
 	pmd = pmd_offset(pud, addr);
 	do {
 		pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
@@ -222,6 +226,7 @@ remap_area_supersections(unsigned long virt, unsigned long pfn,
 {
 	unsigned long addr = virt, end = virt + size;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 
@@ -232,7 +237,8 @@ remap_area_supersections(unsigned long virt, unsigned long pfn,
 	unmap_area_sections(virt, size);
 
 	pgd = pgd_offset_k(virt);
-	pud = pud_offset(pgd, addr);
+	p4d = p4d_offset(pgd, addr);
+	pud = pud_offset(p4d, addr);
 	pmd = pmd_offset(pud, addr);
 	do {
 		unsigned long super_pmd_val, i;
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 88c121ac14b3..4f1f72b75890 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -38,7 +38,7 @@ static inline pte_t get_top_pte(unsigned long va)
 
 static inline pmd_t *pmd_off_k(unsigned long virt)
 {
-	return pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);
+	return pmd_offset(pud_offset(p4d_offset(pgd_offset_k(virt), virt), virt), virt);
 }
 
 struct mem_type {
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 5d0d0f86e790..afd97342b634 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -375,7 +375,8 @@ static pte_t *pte_offset_late_fixmap(pmd_t *dir, unsigned long addr)
 static inline pmd_t * __init fixmap_pmd(unsigned long addr)
 {
 	pgd_t *pgd = pgd_offset_k(addr);
-	pud_t *pud = pud_offset(pgd, addr);
+	p4d_t *p4d = p4d_offset(pgd, addr);
+	pud_t *pud = pud_offset(p4d, addr);
 	pmd_t *pmd = pmd_offset(pud, addr);
 
 	return pmd;
@@ -827,12 +828,12 @@ static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
 	} while (pmd++, addr = next, addr != end);
 }
 
-static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
+static void __init alloc_init_pud(p4d_t *p4d, unsigned long addr,
 				  unsigned long end, phys_addr_t phys,
 				  const struct mem_type *type,
 				  void *(*alloc)(unsigned long sz), bool ng)
 {
-	pud_t *pud = pud_offset(pgd, addr);
+	pud_t *pud = pud_offset(p4d, addr);
 	unsigned long next;
 
 	do {
@@ -842,6 +843,21 @@ static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
 	} while (pud++, addr = next, addr != end);
 }
 
+static void __init alloc_init_p4d(pgd_t *pgd, unsigned long addr,
+				  unsigned long end, phys_addr_t phys,
+				  const struct mem_type *type,
+				  void *(*alloc)(unsigned long sz), bool ng)
+{
+	p4d_t *p4d = p4d_offset(pgd, addr);
+	unsigned long next;
+
+	do {
+		next = p4d_addr_end(addr, end);
+		alloc_init_pud(p4d, addr, next, phys, type, alloc, ng);
+		phys += next - addr;
+	} while (p4d++, addr = next, addr != end);
+}
+
 #ifndef CONFIG_ARM_LPAE
 static void __init create_36bit_mapping(struct mm_struct *mm,
 					struct map_desc *md,
@@ -889,7 +905,8 @@ static void __init create_36bit_mapping(struct mm_struct *mm,
 	pgd = pgd_offset(mm, addr);
 	end = addr + length;
 	do {
-		pud_t *pud = pud_offset(pgd, addr);
+		p4d_t *p4d = p4d_offset(pgd, addr);
+		pud_t *pud = pud_offset(p4d, addr);
 		pmd_t *pmd = pmd_offset(pud, addr);
 		int i;
 
@@ -940,7 +957,7 @@ static void __init __create_mapping(struct mm_struct *mm, struct map_desc *md,
 	do {
 		unsigned long next = pgd_addr_end(addr, end);
 
-		alloc_init_pud(pgd, addr, next, phys, type, alloc, ng);
+		alloc_init_p4d(pgd, addr, next, phys, type, alloc, ng);
 
 		phys += next - addr;
 		addr = next;
@@ -976,7 +993,13 @@ void __init create_mapping_late(struct mm_struct *mm, struct map_desc *md,
 				bool ng)
 {
 #ifdef CONFIG_ARM_LPAE
-	pud_t *pud = pud_alloc(mm, pgd_offset(mm, md->virtual), md->virtual);
+	p4d_t *p4d;
+	pud_t *pud;
+
+	p4d = p4d_alloc(mm, pgd_offset(mm, md->virtual), md->virtual);
+	if (!WARN_ON(!p4d))
+		return;
+	pud = pud_alloc(mm, p4d, md->virtual);
 	if (WARN_ON(!pud))
 		return;
 	pmd_alloc(mm, pud, 0);
diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
index 478bd2c6aa50..c5e1b27046a8 100644
--- a/arch/arm/mm/pgd.c
+++ b/arch/arm/mm/pgd.c
@@ -30,6 +30,7 @@
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *new_pgd, *init_pgd;
+	p4d_t *new_p4d, *init_p4d;
 	pud_t *new_pud, *init_pud;
 	pmd_t *new_pmd, *init_pmd;
 	pte_t *new_pte, *init_pte;
@@ -53,8 +54,12 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 	/*
 	 * Allocate PMD table for modules and pkmap mappings.
 	 */
-	new_pud = pud_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
+	new_p4d = p4d_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
 			    MODULES_VADDR);
+	if (!new_p4d)
+		goto no_p4d;
+
+	new_pud = pud_alloc(mm, new_p4d, MODULES_VADDR);
 	if (!new_pud)
 		goto no_pud;
 
@@ -69,7 +74,11 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 		 * contains the machine vectors. The vectors are always high
 		 * with LPAE.
 		 */
-		new_pud = pud_alloc(mm, new_pgd, 0);
+		new_p4d = p4d_alloc(mm, new_pgd, 0);
+		if (!new_p4d)
+			goto no_p4d;
+
+		new_pud = pud_alloc(mm, new_p4d, 0);
 		if (!new_pud)
 			goto no_pud;
 
@@ -91,7 +100,8 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 		pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
 #endif
 
-		init_pud = pud_offset(init_pgd, 0);
+		init_p4d = p4d_offset(init_pgd, 0);
+		init_pud = pud_offset(init_p4d, 0);
 		init_pmd = pmd_offset(init_pud, 0);
 		init_pte = pte_offset_map(init_pmd, 0);
 		set_pte_ext(new_pte + 0, init_pte[0], 0);
@@ -108,6 +118,8 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 no_pmd:
 	pud_free(mm, new_pud);
 no_pud:
+	p4d_free(mm, new_p4d);
+no_p4d:
 	__pgd_free(new_pgd);
 no_pgd:
 	return NULL;
@@ -116,6 +128,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
 {
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pgtable_t pte;
@@ -127,7 +140,11 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
 	if (pgd_none_or_clear_bad(pgd))
 		goto no_pgd;
 
-	pud = pud_offset(pgd, 0);
+	p4d = p4d_offset(pgd, 0);
+	if (p4d_none_or_clear_bad(p4d))
+		goto no_p4d;
+
+	pud = pud_offset(p4d, 0);
 	if (pud_none_or_clear_bad(pud))
 		goto no_pud;
 
@@ -144,8 +161,11 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
 	pmd_free(mm, pmd);
 	mm_dec_nr_pmds(mm);
 no_pud:
-	pgd_clear(pgd);
+	p4d_clear(p4d);
 	pud_free(mm, pud);
+no_p4d:
+	pgd_clear(pgd);
+	p4d_free(mm, p4d);
 no_pgd:
 #ifdef CONFIG_ARM_LPAE
 	/*
@@ -156,15 +176,21 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
 			continue;
 		if (pgd_val(*pgd) & L_PGD_SWAPPER)
 			continue;
-		pud = pud_offset(pgd, 0);
+		p4d = p4d_offset(pgd, 0);
+		if (p4d_none_or_clear_bad(p4d))
+			continue;
+		pud = pud_offset(p4d, 0);
 		if (pud_none_or_clear_bad(pud))
 			continue;
 		pmd = pmd_offset(pud, 0);
 		pud_clear(pud);
 		pmd_free(mm, pmd);
 		mm_dec_nr_pmds(mm);
-		pgd_clear(pgd);
+		p4d_clear(p4d);
 		pud_free(mm, pud);
+		mm_dec_nr_puds(mm);
+		pgd_clear(pgd);
+		p4d_free(mm, p4d);
 	}
 #endif
 	__pgd_free(pgd_base);
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 53d846f1bfe7..1f9bf19ac553 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -172,8 +172,8 @@ void kvm_clear_hyp_idmap(void);
 	__pmd(__phys_to_pmd_val(__pa(ptep)) | PMD_TYPE_TABLE)
 #define kvm_mk_pud(pmdp)					\
 	__pud(__phys_to_pud_val(__pa(pmdp)) | PMD_TYPE_TABLE)
-#define kvm_mk_pgd(pudp)					\
-	__pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE)
+#define kvm_mk_p4d(pmdp)					\
+	__p4d(__phys_to_p4d_val(__pa(pmdp)) | PUD_TYPE_TABLE)
 
 #define kvm_set_pud(pudp, pud)		set_pud(pudp, pud)
 
@@ -299,6 +299,12 @@ static inline bool kvm_s2pud_young(pud_t pud)
 #define hyp_pud_table_empty(pudp) kvm_page_empty(pudp)
 #endif
 
+#ifdef __PAGETABLE_P4D_FOLDED
+#define hyp_p4d_table_empty(p4dp) (0)
+#else
+#define hyp_p4d_table_empty(p4dp) kvm_page_empty(p4dp)
+#endif
+
 struct kvm;
 
 #define kvm_flush_dcache_to_poc(a,l)	__flush_dcache_area((a), (l))
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 172d76fa0245..58e93583ddb6 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -73,17 +73,17 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pudp)
 	free_page((unsigned long)pudp);
 }
 
-static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
+static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
 {
-	set_pgd(pgdp, __pgd(__phys_to_pgd_val(pudp) | prot));
+	set_p4d(p4dp, __p4d(__phys_to_p4d_val(pudp) | prot));
 }
 
-static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgdp, pud_t *pudp)
+static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp)
 {
-	__pgd_populate(pgdp, __pa(pudp), PUD_TYPE_TABLE);
+	__p4d_populate(p4dp, __pa(pudp), PUD_TYPE_TABLE);
 }
 #else
-static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
+static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
 {
 	BUILD_BUG();
 }
diff --git a/arch/arm64/include/asm/pgtable-types.h b/arch/arm64/include/asm/pgtable-types.h
index acb0751a6606..b8f158ae2527 100644
--- a/arch/arm64/include/asm/pgtable-types.h
+++ b/arch/arm64/include/asm/pgtable-types.h
@@ -14,6 +14,7 @@
 typedef u64 pteval_t;
 typedef u64 pmdval_t;
 typedef u64 pudval_t;
+typedef u64 p4dval_t;
 typedef u64 pgdval_t;
 
 /*
@@ -44,13 +45,11 @@ typedef struct { pteval_t pgprot; } pgprot_t;
 #define __pgprot(x)	((pgprot_t) { (x) } )
 
 #if CONFIG_PGTABLE_LEVELS == 2
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>
 #elif CONFIG_PGTABLE_LEVELS == 3
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopud.h>
 #elif CONFIG_PGTABLE_LEVELS == 4
-#include <asm-generic/5level-fixup.h>
+#include <asm-generic/pgtable-nop4d.h>
 #endif
 
 #endif	/* __ASM_PGTABLE_TYPES_H */
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index cd5de0e40bfa..a1a74eb8e411 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -298,6 +298,11 @@ static inline pte_t pgd_pte(pgd_t pgd)
 	return __pte(pgd_val(pgd));
 }
 
+static inline pte_t p4d_pte(p4d_t p4d)
+{
+	return __pte(p4d_val(p4d));
+}
+
 static inline pte_t pud_pte(pud_t pud)
 {
 	return __pte(pud_val(pud));
@@ -401,6 +406,9 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd)
 
 #define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
 
+#define __p4d_to_phys(p4d)	__pte_to_phys(p4d_pte(p4d))
+#define __phys_to_p4d_val(phys)	__phys_to_pte_val(phys)
+
 #define __pgd_to_phys(pgd)	__pte_to_phys(pgd_pte(pgd))
 #define __phys_to_pgd_val(phys)	__phys_to_pte_val(phys)
 
@@ -586,49 +594,50 @@ static inline phys_addr_t pud_page_paddr(pud_t pud)
 
 #define pud_ERROR(pud)		__pud_error(__FILE__, __LINE__, pud_val(pud))
 
-#define pgd_none(pgd)		(!pgd_val(pgd))
-#define pgd_bad(pgd)		(!(pgd_val(pgd) & 2))
-#define pgd_present(pgd)	(pgd_val(pgd))
+#define p4d_none(p4d)		(!p4d_val(p4d))
+#define p4d_bad(p4d)		(!(p4d_val(p4d) & 2))
+#define p4d_present(p4d)	(p4d_val(p4d))
 
-static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
+static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
 {
-	if (in_swapper_pgdir(pgdp)) {
-		set_swapper_pgd(pgdp, pgd);
+	if (in_swapper_pgdir(p4dp)) {
+		set_swapper_pgd((pgd_t *)p4dp, __pgd(p4d_val(p4d)));
 		return;
 	}
 
-	WRITE_ONCE(*pgdp, pgd);
+	WRITE_ONCE(*p4dp, p4d);
 	dsb(ishst);
 	isb();
 }
 
-static inline void pgd_clear(pgd_t *pgdp)
+static inline void p4d_clear(p4d_t *p4dp)
 {
-	set_pgd(pgdp, __pgd(0));
+	set_p4d(p4dp, __p4d(0));
 }
 
-static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
+static inline phys_addr_t p4d_page_paddr(p4d_t p4d)
 {
-	return __pgd_to_phys(pgd);
+	return __p4d_to_phys(p4d);
 }
 
 /* Find an entry in the frst-level page table. */
 #define pud_index(addr)		(((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
 
-#define pud_offset_phys(dir, addr)	(pgd_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
+#define pud_offset_phys(dir, addr)	(p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
 #define pud_offset(dir, addr)		((pud_t *)__va(pud_offset_phys((dir), (addr))))
 
 #define pud_set_fixmap(addr)		((pud_t *)set_fixmap_offset(FIX_PUD, addr))
-#define pud_set_fixmap_offset(pgd, addr)	pud_set_fixmap(pud_offset_phys(pgd, addr))
+#define pud_set_fixmap_offset(p4d, addr)	pud_set_fixmap(pud_offset_phys(p4d, addr))
 #define pud_clear_fixmap()		clear_fixmap(FIX_PUD)
 
-#define pgd_page(pgd)		pfn_to_page(__phys_to_pfn(__pgd_to_phys(pgd)))
+#define p4d_page(p4d)		pfn_to_page(__phys_to_pfn(__p4d_to_phys(p4d)))
 
 /* use ONLY for statically allocated translation tables */
 #define pud_offset_kimg(dir,addr)	((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
 
 #else
 
+#define p4d_page_paddr(p4d)	({ BUILD_BUG(); 0;})
 #define pgd_page_paddr(pgd)	({ BUILD_BUG(); 0;})
 
 /* Match pud_offset folding in <asm/generic/pgtable-nopud.h> */
diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h
index 326aac658b9d..9a364aeae5fb 100644
--- a/arch/arm64/include/asm/stage2_pgtable.h
+++ b/arch/arm64/include/asm/stage2_pgtable.h
@@ -68,41 +68,67 @@ static inline bool kvm_stage2_has_pud(struct kvm *kvm)
 #define S2_PUD_SIZE			(1UL << S2_PUD_SHIFT)
 #define S2_PUD_MASK			(~(S2_PUD_SIZE - 1))
 
-static inline bool stage2_pgd_none(struct kvm *kvm, pgd_t pgd)
+#define stage2_pgd_none(kvm, pgd)		pgd_none(pgd)
+#define stage2_pgd_clear(kvm, pgd)		pgd_clear(pgd)
+#define stage2_pgd_present(kvm, pgd)		pgd_present(pgd)
+#define stage2_pgd_populate(kvm, pgd, p4d)	pgd_populate(NULL, pgd, p4d)
+
+static inline p4d_t *stage2_p4d_offset(struct kvm *kvm,
+				       pgd_t *pgd, unsigned long address)
+{
+	return p4d_offset(pgd, address);
+}
+
+static inline void stage2_p4d_free(struct kvm *kvm, p4d_t *p4d)
+{
+}
+
+static inline bool stage2_p4d_table_empty(struct kvm *kvm, p4d_t *p4dp)
+{
+	return false;
+}
+
+static inline phys_addr_t stage2_p4d_addr_end(struct kvm *kvm,
+					      phys_addr_t addr, phys_addr_t end)
+{
+	return end;
+}
+
+static inline bool stage2_p4d_none(struct kvm *kvm, p4d_t p4d)
 {
 	if (kvm_stage2_has_pud(kvm))
-		return pgd_none(pgd);
+		return p4d_none(p4d);
 	else
 		return 0;
 }
 
-static inline void stage2_pgd_clear(struct kvm *kvm, pgd_t *pgdp)
+static inline void stage2_p4d_clear(struct kvm *kvm, p4d_t *p4dp)
 {
 	if (kvm_stage2_has_pud(kvm))
-		pgd_clear(pgdp);
+		p4d_clear(p4dp);
 }
 
-static inline bool stage2_pgd_present(struct kvm *kvm, pgd_t pgd)
+static inline bool stage2_p4d_present(struct kvm *kvm, p4d_t p4d)
 {
 	if (kvm_stage2_has_pud(kvm))
-		return pgd_present(pgd);
+		return p4d_present(p4d);
 	else
 		return 1;
 }
 
-static inline void stage2_pgd_populate(struct kvm *kvm, pgd_t *pgd, pud_t *pud)
+static inline void stage2_p4d_populate(struct kvm *kvm, p4d_t *p4d, pud_t *pud)
 {
 	if (kvm_stage2_has_pud(kvm))
-		pgd_populate(NULL, pgd, pud);
+		p4d_populate(NULL, p4d, pud);
 }
 
 static inline pud_t *stage2_pud_offset(struct kvm *kvm,
-				       pgd_t *pgd, unsigned long address)
+				       p4d_t *p4d, unsigned long address)
 {
 	if (kvm_stage2_has_pud(kvm))
-		return pud_offset(pgd, address);
+		return pud_offset(p4d, address);
 	else
-		return (pud_t *)pgd;
+		return (pud_t *)p4d;
 }
 
 static inline void stage2_pud_free(struct kvm *kvm, pud_t *pud)
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index a96b2921d22c..24d1b04525c2 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -203,6 +203,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
 	int rc = 0;
 	pgd_t *trans_pgd;
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp;
 	pmd_t *pmdp;
 	pte_t *ptep;
@@ -232,7 +233,17 @@ static int create_safe_exec_page(void *src_start, size_t length,
 		pgd_populate(&init_mm, pgdp, pudp);
 	}
 
-	pudp = pud_offset(pgdp, dst_addr);
+	p4dp = p4d_offset(pgdp, dst_addr);
+	if (p4d_none(READ_ONCE(*p4dp))) {
+		pudp = allocator(mask);
+		if (!pudp) {
+			rc = -ENOMEM;
+			goto out;
+		}
+		p4d_populate(&init_mm, p4dp, pudp);
+	}
+
+	pudp = pud_offset(p4dp, dst_addr);
 	if (pud_none(READ_ONCE(*pudp))) {
 		pmdp = allocator(mask);
 		if (!pmdp) {
@@ -422,7 +433,7 @@ static int copy_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,
 	return 0;
 }
 
-static int copy_pud(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
+static int copy_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,
 		    unsigned long end)
 {
 	pud_t *dst_pudp;
@@ -430,15 +441,15 @@ static int copy_pud(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
 	unsigned long next;
 	unsigned long addr = start;
 
-	if (pgd_none(READ_ONCE(*dst_pgdp))) {
+	if (p4d_none(READ_ONCE(*dst_p4dp))) {
 		dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
 		if (!dst_pudp)
 			return -ENOMEM;
-		pgd_populate(&init_mm, dst_pgdp, dst_pudp);
+		p4d_populate(&init_mm, dst_p4dp, dst_pudp);
 	}
-	dst_pudp = pud_offset(dst_pgdp, start);
+	dst_pudp = pud_offset(dst_p4dp, start);
 
-	src_pudp = pud_offset(src_pgdp, start);
+	src_pudp = pud_offset(src_p4dp, start);
 	do {
 		pud_t pud = READ_ONCE(*src_pudp);
 
@@ -457,6 +468,27 @@ static int copy_pud(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
 	return 0;
 }
 
+static int copy_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
+		    unsigned long end)
+{
+	p4d_t *dst_p4dp;
+	p4d_t *src_p4dp;
+	unsigned long next;
+	unsigned long addr = start;
+
+	dst_p4dp = p4d_offset(dst_pgdp, start);
+	src_p4dp = p4d_offset(src_pgdp, start);
+	do {
+		next = p4d_addr_end(addr, end);
+		if (p4d_none(READ_ONCE(*src_p4dp)))
+			continue;
+		if (copy_pud(dst_p4dp, src_p4dp, addr, next))
+			return -ENOMEM;
+	} while (dst_p4dp++, src_p4dp++, addr = next, addr != end);
+
+	return 0;
+}
+
 static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
 			    unsigned long end)
 {
@@ -469,7 +501,7 @@ static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(READ_ONCE(*src_pgdp)))
 			continue;
-		if (copy_pud(dst_pgdp, src_pgdp, addr, next))
+		if (copy_p4d(dst_pgdp, src_pgdp, addr, next))
 			return -ENOMEM;
 	} while (dst_pgdp++, src_pgdp++, addr = next, addr != end);
 
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 0a920b538a89..86a02660f321 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -179,6 +179,10 @@ static struct pg_level pg_level[] = {
 		.name	= "PGD",
 		.bits	= pte_bits,
 		.num	= ARRAY_SIZE(pte_bits),
+	}, { /* p4d */
+		.name	= "P4D",
+		.bits	= pte_bits,
+		.num	= ARRAY_SIZE(pte_bits),
 	}, { /* pud */
 		.name	= (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
 		.bits	= pte_bits,
@@ -323,11 +327,11 @@ static void walk_pmd(struct pg_state *st, pud_t *pudp, unsigned long start,
 	} while (pmdp++, addr = next, addr != end);
 }
 
-static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start,
+static void walk_pud(struct pg_state *st, p4d_t *p4dp, unsigned long start,
 		     unsigned long end)
 {
 	unsigned long next, addr = start;
-	pud_t *pudp = pud_offset(pgdp, start);
+	pud_t *pudp = pud_offset(p4dp, start);
 
 	do {
 		pud_t pud = READ_ONCE(*pudp);
@@ -342,6 +346,25 @@ static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start,
 	} while (pudp++, addr = next, addr != end);
 }
 
+static void walk_p4d(struct pg_state *st, pgd_t *pgdp, unsigned long start,
+		     unsigned long end)
+{
+	unsigned long next, addr = start;
+	p4d_t *p4dp = p4d_offset(pgdp, start);
+
+	do {
+		p4d_t p4d = READ_ONCE(*p4dp);
+		next = p4d_addr_end(addr, end);
+
+		if (p4d_none(p4d)) {
+			note_page(st, addr, 2, p4d_val(p4d));
+		} else {
+			BUG_ON(p4d_bad(p4d));
+			walk_pud(st, p4dp, addr, next);
+		}
+	} while (p4dp++, addr = next, addr != end);
+}
+
 static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
 		     unsigned long start)
 {
@@ -357,7 +380,7 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
 			note_page(st, addr, 1, pgd_val(pgd));
 		} else {
 			BUG_ON(pgd_bad(pgd));
-			walk_pud(st, pgdp, addr, next);
+			walk_p4d(st, pgdp, addr, next);
 		}
 	} while (pgdp++, addr = next, addr != end);
 }
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 85566d32958f..fa6e7960f7d1 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -145,6 +145,7 @@ static void show_pte(unsigned long addr)
 	pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
 
 	do {
+		p4d_t *p4dp, p4d;
 		pud_t *pudp, pud;
 		pmd_t *pmdp, pmd;
 		pte_t *ptep, pte;
@@ -152,7 +153,13 @@ static void show_pte(unsigned long addr)
 		if (pgd_none(pgd) || pgd_bad(pgd))
 			break;
 
-		pudp = pud_offset(pgdp, addr);
+		p4dp = p4d_offset(pgdp, addr);
+		p4d = READ_ONCE(*p4dp);
+		pr_cont(", p4d=%016llx", p4d_val(p4d));
+		if (p4d_none(p4d) || p4d_bad(p4d))
+			break;
+
+		pudp = pud_offset(p4dp, addr);
 		pud = READ_ONCE(*pudp);
 		pr_cont(", pud=%016llx", pud_val(pud));
 		if (pud_none(pud) || pud_bad(pud))
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index bbeb6a5a6ba6..b8a9f26f3790 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -67,11 +67,13 @@ static int find_num_contig(struct mm_struct *mm, unsigned long addr,
 			   pte_t *ptep, size_t *pgsize)
 {
 	pgd_t *pgdp = pgd_offset(mm, addr);
+	p4d_t *p4dp;
 	pud_t *pudp;
 	pmd_t *pmdp;
 
 	*pgsize = PAGE_SIZE;
-	pudp = pud_offset(pgdp, addr);
+	p4dp = p4d_offset(pgdp, addr);
+	pudp = pud_offset(p4dp, addr);
 	pmdp = pmd_offset(pudp, addr);
 	if ((pte_t *)pmdp == ptep) {
 		*pgsize = PMD_SIZE;
@@ -217,12 +219,14 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
 		      unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp;
 	pmd_t *pmdp;
 	pte_t *ptep = NULL;
 
 	pgdp = pgd_offset(mm, addr);
-	pudp = pud_alloc(mm, pgdp, addr);
+	p4dp = p4d_offset(pgdp, addr);
+	pudp = pud_alloc(mm, p4dp, addr);
 	if (!pudp)
 		return NULL;
 
@@ -259,6 +263,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
 		       unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp, pud;
 	pmd_t *pmdp, pmd;
 
@@ -266,7 +271,11 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
 	if (!pgd_present(READ_ONCE(*pgdp)))
 		return NULL;
 
-	pudp = pud_offset(pgdp, addr);
+	p4dp = p4d_offset(pgdp, addr);
+	if (!p4d_present(READ_ONCE(*p4dp)))
+		return NULL;
+
+	pudp = pud_offset(p4dp, addr);
 	pud = READ_ONCE(*pudp);
 	if (sz != PUD_SIZE && pud_none(pud))
 		return NULL;
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index f87a32484ea8..2339811f317b 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -84,17 +84,17 @@ static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
 	return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
 }
 
-static pud_t *__init kasan_pud_offset(pgd_t *pgdp, unsigned long addr, int node,
+static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node,
 				      bool early)
 {
-	if (pgd_none(READ_ONCE(*pgdp))) {
+	if (p4d_none(READ_ONCE(*p4dp))) {
 		phys_addr_t pud_phys = early ?
 				__pa_symbol(kasan_early_shadow_pud)
 					: kasan_alloc_zeroed_page(node);
-		__pgd_populate(pgdp, pud_phys, PMD_TYPE_TABLE);
+		__p4d_populate(p4dp, pud_phys, PMD_TYPE_TABLE);
 	}
 
-	return early ? pud_offset_kimg(pgdp, addr) : pud_offset(pgdp, addr);
+	return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
 }
 
 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
@@ -126,11 +126,11 @@ static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
 	} while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
 }
 
-static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
+static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
 				      unsigned long end, int node, bool early)
 {
 	unsigned long next;
-	pud_t *pudp = kasan_pud_offset(pgdp, addr, node, early);
+	pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
 
 	do {
 		next = pud_addr_end(addr, end);
@@ -138,6 +138,18 @@ static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
 	} while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
 }
 
+static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
+				      unsigned long end, int node, bool early)
+{
+	unsigned long next;
+	p4d_t *p4dp = p4d_offset(pgdp, addr);
+
+	do {
+		next = p4d_addr_end(addr, end);
+		kasan_pud_populate(p4dp, addr, next, node, early);
+	} while (p4dp++, addr = next, addr != end);
+}
+
 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
 				      int node, bool early)
 {
@@ -147,7 +159,7 @@ static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
 	pgdp = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		kasan_pud_populate(pgdp, addr, next, node, early);
+		kasan_p4d_populate(pgdp, addr, next, node, early);
 	} while (pgdp++, addr = next, addr != end);
 }
 
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 40797cbfba2d..b59a3cdc3c01 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -289,18 +289,19 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
 {
 	unsigned long next;
 	pud_t *pudp;
-	pgd_t pgd = READ_ONCE(*pgdp);
+	p4d_t *p4dp = p4d_offset(pgdp, addr);
+	p4d_t p4d = READ_ONCE(*p4dp);
 
-	if (pgd_none(pgd)) {
+	if (p4d_none(p4d)) {
 		phys_addr_t pud_phys;
 		BUG_ON(!pgtable_alloc);
 		pud_phys = pgtable_alloc(PUD_SHIFT);
-		__pgd_populate(pgdp, pud_phys, PUD_TYPE_TABLE);
-		pgd = READ_ONCE(*pgdp);
+		__p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE);
+		p4d = READ_ONCE(*p4dp);
 	}
-	BUG_ON(pgd_bad(pgd));
+	BUG_ON(p4d_bad(p4d));
 
-	pudp = pud_set_fixmap_offset(pgdp, addr);
+	pudp = pud_set_fixmap_offset(p4dp, addr);
 	do {
 		pud_t old_pud = READ_ONCE(*pudp);
 
@@ -647,6 +648,7 @@ static void __init map_kernel(pgd_t *pgdp)
 			READ_ONCE(*pgd_offset_k(FIXADDR_START)));
 	} else if (CONFIG_PGTABLE_LEVELS > 3) {
 		pgd_t *bm_pgdp;
+		p4d_t *bm_p4dp;
 		pud_t *bm_pudp;
 		/*
 		 * The fixmap shares its top level pgd entry with the kernel
@@ -656,7 +658,8 @@ static void __init map_kernel(pgd_t *pgdp)
 		 */
 		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 		bm_pgdp = pgd_offset_raw(pgdp, FIXADDR_START);
-		bm_pudp = pud_set_fixmap_offset(bm_pgdp, FIXADDR_START);
+		bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
+		bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
 		pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
 		pud_clear_fixmap();
 	} else {
@@ -690,6 +693,7 @@ void __init paging_init(void)
 int kern_addr_valid(unsigned long addr)
 {
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp, pud;
 	pmd_t *pmdp, pmd;
 	pte_t *ptep, pte;
@@ -701,7 +705,11 @@ int kern_addr_valid(unsigned long addr)
 	if (pgd_none(READ_ONCE(*pgdp)))
 		return 0;
 
-	pudp = pud_offset(pgdp, addr);
+	p4dp = p4d_offset(pgdp, addr);
+	if (p4d_none(READ_ONCE(*p4dp)))
+		return 0;
+
+	pudp = pud_offset(p4dp, addr);
 	pud = READ_ONCE(*pudp);
 	if (pud_none(pud))
 		return 0;
@@ -738,6 +746,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 	unsigned long addr = start;
 	unsigned long next;
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp;
 	pmd_t *pmdp;
 
@@ -748,7 +757,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 		if (!pgdp)
 			return -ENOMEM;
 
-		pudp = vmemmap_pud_populate(pgdp, addr, node);
+		p4dp = vmemmap_p4d_populate(pgdp, addr, node);
+		if (!p4dp)
+			return -ENOMEM;
+
+		pudp = vmemmap_pud_populate(p4dp, addr, node);
 		if (!pudp)
 			return -ENOMEM;
 
@@ -777,11 +790,12 @@ void vmemmap_free(unsigned long start, unsigned long end,
 static inline pud_t * fixmap_pud(unsigned long addr)
 {
 	pgd_t *pgdp = pgd_offset_k(addr);
-	pgd_t pgd = READ_ONCE(*pgdp);
+	p4d_t *p4dp = p4d_offset(pgdp, addr);
+	p4d_t p4d = READ_ONCE(*p4dp);
 
-	BUG_ON(pgd_none(pgd) || pgd_bad(pgd));
+	BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
 
-	return pud_offset_kimg(pgdp, addr);
+	return pud_offset_kimg(p4dp, addr);
 }
 
 static inline pmd_t * fixmap_pmd(unsigned long addr)
@@ -807,25 +821,27 @@ static inline pte_t * fixmap_pte(unsigned long addr)
  */
 void __init early_fixmap_init(void)
 {
-	pgd_t *pgdp, pgd;
+	pgd_t *pgdp;
+	p4d_t *p4dp, p4d;
 	pud_t *pudp;
 	pmd_t *pmdp;
 	unsigned long addr = FIXADDR_START;
 
 	pgdp = pgd_offset_k(addr);
-	pgd = READ_ONCE(*pgdp);
+	p4dp = p4d_offset(pgdp, addr);
+	p4d = READ_ONCE(*p4dp);
 	if (CONFIG_PGTABLE_LEVELS > 3 &&
-	    !(pgd_none(pgd) || pgd_page_paddr(pgd) == __pa_symbol(bm_pud))) {
+	    !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
 		/*
 		 * We only end up here if the kernel mapping and the fixmap
 		 * share the top level pgd entry, which should only happen on
 		 * 16k/4 levels configurations.
 		 */
 		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
-		pudp = pud_offset_kimg(pgdp, addr);
+		pudp = pud_offset_kimg(p4dp, addr);
 	} else {
-		if (pgd_none(pgd))
-			__pgd_populate(pgdp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
+		if (p4d_none(p4d))
+			__p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
 		pudp = fixmap_pud(addr);
 	}
 	if (pud_none(READ_ONCE(*pudp)))
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 9ce7bd9d4d9c..78ece756ca89 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -198,6 +198,7 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
 bool kernel_page_present(struct page *page)
 {
 	pgd_t *pgdp;
+	p4d_t *p4dp;
 	pud_t *pudp, pud;
 	pmd_t *pmdp, pmd;
 	pte_t *ptep;
@@ -210,7 +211,11 @@ bool kernel_page_present(struct page *page)
 	if (pgd_none(READ_ONCE(*pgdp)))
 		return false;
 
-	pudp = pud_offset(pgdp, addr);
+	p4dp = p4d_offset(pgdp, addr);
+	if (p4d_none(READ_ONCE(*p4dp)))
+		return false;
+
+	pudp = pud_offset(p4dp, addr);
 	pud = READ_ONCE(*pudp);
 	if (pud_none(pud))
 		return false;
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 0b32a904a1bb..2c9fba63f68a 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -159,13 +159,22 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
 
 static void clear_stage2_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)
 {
-	pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, pgd, 0UL);
+	p4d_t *p4d_table __maybe_unused = stage2_p4d_offset(kvm, pgd, 0UL);
 	stage2_pgd_clear(kvm, pgd);
 	kvm_tlb_flush_vmid_ipa(kvm, addr);
-	stage2_pud_free(kvm, pud_table);
+	stage2_p4d_free(kvm, p4d_table);
 	put_page(virt_to_page(pgd));
 }
 
+static void clear_stage2_p4d_entry(struct kvm *kvm, p4d_t *p4d, phys_addr_t addr)
+{
+	pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, p4d, 0);
+	stage2_p4d_clear(kvm, p4d);
+	kvm_tlb_flush_vmid_ipa(kvm, addr);
+	stage2_pud_free(kvm, pud_table);
+	put_page(virt_to_page(p4d));
+}
+
 static void clear_stage2_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
 {
 	pmd_t *pmd_table __maybe_unused = stage2_pmd_offset(kvm, pud, 0);
@@ -209,12 +218,20 @@ static inline void kvm_pud_populate(pud_t *pudp, pmd_t *pmdp)
 	dsb(ishst);
 }
 
-static inline void kvm_pgd_populate(pgd_t *pgdp, pud_t *pudp)
+static inline void kvm_p4d_populate(p4d_t *p4dp, pud_t *pudp)
 {
-	WRITE_ONCE(*pgdp, kvm_mk_pgd(pudp));
+	WRITE_ONCE(*p4dp, kvm_mk_p4d(pudp));
 	dsb(ishst);
 }
 
+static inline void kvm_pgd_populate(pgd_t *pgdp, p4d_t *p4dp)
+{
+#ifndef __PAGETABLE_P4D_FOLDED
+	WRITE_ONCE(*pgdp, kvm_mk_pgd(p4dp));
+	dsb(ishst);
+#endif
+}
+
 /*
  * Unmapping vs dcache management:
  *
@@ -294,13 +311,13 @@ static void unmap_stage2_pmds(struct kvm *kvm, pud_t *pud,
 		clear_stage2_pud_entry(kvm, pud, start_addr);
 }
 
-static void unmap_stage2_puds(struct kvm *kvm, pgd_t *pgd,
+static void unmap_stage2_puds(struct kvm *kvm, p4d_t *p4d,
 		       phys_addr_t addr, phys_addr_t end)
 {
 	phys_addr_t next, start_addr = addr;
 	pud_t *pud, *start_pud;
 
-	start_pud = pud = stage2_pud_offset(kvm, pgd, addr);
+	start_pud = pud = stage2_pud_offset(kvm, p4d, addr);
 	do {
 		next = stage2_pud_addr_end(kvm, addr, end);
 		if (!stage2_pud_none(kvm, *pud)) {
@@ -318,6 +335,23 @@ static void unmap_stage2_puds(struct kvm *kvm, pgd_t *pgd,
 	} while (pud++, addr = next, addr != end);
 
 	if (stage2_pud_table_empty(kvm, start_pud))
+		clear_stage2_p4d_entry(kvm, p4d, start_addr);
+}
+
+static void unmap_stage2_p4ds(struct kvm *kvm, pgd_t *pgd,
+		       phys_addr_t addr, phys_addr_t end)
+{
+	phys_addr_t next, start_addr = addr;
+	p4d_t *p4d, *start_p4d;
+
+	start_p4d = p4d = stage2_p4d_offset(kvm, pgd, addr);
+	do {
+		next = stage2_p4d_addr_end(kvm, addr, end);
+		if (!stage2_p4d_none(kvm, *p4d))
+			unmap_stage2_puds(kvm, p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+
+	if (stage2_p4d_table_empty(kvm, start_p4d))
 		clear_stage2_pgd_entry(kvm, pgd, start_addr);
 }
 
@@ -352,7 +386,7 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
 			break;
 		next = stage2_pgd_addr_end(kvm, addr, end);
 		if (!stage2_pgd_none(kvm, *pgd))
-			unmap_stage2_puds(kvm, pgd, addr, next);
+			unmap_stage2_p4ds(kvm, pgd, addr, next);
 		/*
 		 * If the range is too large, release the kvm->mmu_lock
 		 * to prevent starvation and lockup detector warnings.
@@ -392,13 +426,13 @@ static void stage2_flush_pmds(struct kvm *kvm, pud_t *pud,
 	} while (pmd++, addr = next, addr != end);
 }
 
-static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
+static void stage2_flush_puds(struct kvm *kvm, p4d_t *p4d,
 			      phys_addr_t addr, phys_addr_t end)
 {
 	pud_t *pud;
 	phys_addr_t next;
 
-	pud = stage2_pud_offset(kvm, pgd, addr);
+	pud = stage2_pud_offset(kvm, p4d, addr);
 	do {
 		next = stage2_pud_addr_end(kvm, addr, end);
 		if (!stage2_pud_none(kvm, *pud)) {
@@ -410,6 +444,20 @@ static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
 	} while (pud++, addr = next, addr != end);
 }
 
+static void stage2_flush_p4ds(struct kvm *kvm, pgd_t *pgd,
+			      phys_addr_t addr, phys_addr_t end)
+{
+	p4d_t *p4d;
+	phys_addr_t next;
+
+	p4d = stage2_p4d_offset(kvm, pgd, addr);
+	do {
+		next = stage2_p4d_addr_end(kvm, addr, end);
+		if (!stage2_p4d_none(kvm, *p4d))
+			stage2_flush_puds(kvm, p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+}
+
 static void stage2_flush_memslot(struct kvm *kvm,
 				 struct kvm_memory_slot *memslot)
 {
@@ -422,7 +470,7 @@ static void stage2_flush_memslot(struct kvm *kvm,
 	do {
 		next = stage2_pgd_addr_end(kvm, addr, end);
 		if (!stage2_pgd_none(kvm, *pgd))
-			stage2_flush_puds(kvm, pgd, addr, next);
+			stage2_flush_p4ds(kvm, pgd, addr, next);
 	} while (pgd++, addr = next, addr != end);
 }
 
@@ -452,12 +500,21 @@ static void stage2_flush_vm(struct kvm *kvm)
 
 static void clear_hyp_pgd_entry(pgd_t *pgd)
 {
-	pud_t *pud_table __maybe_unused = pud_offset(pgd, 0UL);
+	p4d_t *p4d_table __maybe_unused = p4d_offset(pgd, 0UL);
 	pgd_clear(pgd);
-	pud_free(NULL, pud_table);
+	p4d_free(NULL, p4d_table);
 	put_page(virt_to_page(pgd));
 }
 
+static void clear_hyp_p4d_entry(p4d_t *p4d)
+{
+	pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
+	VM_BUG_ON(p4d_huge(*p4d));
+	p4d_clear(p4d);
+	pud_free(NULL, pud_table);
+	put_page(virt_to_page(p4d));
+}
+
 static void clear_hyp_pud_entry(pud_t *pud)
 {
 	pmd_t *pmd_table __maybe_unused = pmd_offset(pud, 0);
@@ -509,12 +566,12 @@ static void unmap_hyp_pmds(pud_t *pud, phys_addr_t addr, phys_addr_t end)
 		clear_hyp_pud_entry(pud);
 }
 
-static void unmap_hyp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
+static void unmap_hyp_puds(p4d_t *p4d, phys_addr_t addr, phys_addr_t end)
 {
 	phys_addr_t next;
 	pud_t *pud, *start_pud;
 
-	start_pud = pud = pud_offset(pgd, addr);
+	start_pud = pud = pud_offset(p4d, addr);
 	do {
 		next = pud_addr_end(addr, end);
 		/* Hyp doesn't use huge puds */
@@ -523,6 +580,23 @@ static void unmap_hyp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
 	} while (pud++, addr = next, addr != end);
 
 	if (hyp_pud_table_empty(start_pud))
+		clear_hyp_p4d_entry(p4d);
+}
+
+static void unmap_hyp_p4ds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
+{
+	phys_addr_t next;
+	p4d_t *p4d, *start_p4d;
+
+	start_p4d = p4d = p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+		/* Hyp doesn't use huge p4ds */
+		if (!p4d_none(*p4d))
+			unmap_hyp_puds(p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+
+	if (hyp_p4d_table_empty(start_p4d))
 		clear_hyp_pgd_entry(pgd);
 }
 
@@ -546,7 +620,7 @@ static void __unmap_hyp_range(pgd_t *pgdp, unsigned long ptrs_per_pgd,
 	do {
 		next = pgd_addr_end(addr, end);
 		if (!pgd_none(*pgd))
-			unmap_hyp_puds(pgd, addr, next);
+			unmap_hyp_p4ds(pgd, addr, next);
 	} while (pgd++, addr = next, addr != end);
 }
 
@@ -656,7 +730,7 @@ static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
 	return 0;
 }
 
-static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
+static int create_hyp_pud_mappings(p4d_t *p4d, unsigned long start,
 				   unsigned long end, unsigned long pfn,
 				   pgprot_t prot)
 {
@@ -667,7 +741,7 @@ static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
 
 	addr = start;
 	do {
-		pud = pud_offset(pgd, addr);
+		pud = pud_offset(p4d, addr);
 
 		if (pud_none_or_clear_bad(pud)) {
 			pmd = pmd_alloc_one(NULL, addr);
@@ -689,12 +763,45 @@ static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
 	return 0;
 }
 
+static int create_hyp_p4d_mappings(pgd_t *pgd, unsigned long start,
+				   unsigned long end, unsigned long pfn,
+				   pgprot_t prot)
+{
+	p4d_t *p4d;
+	pud_t *pud;
+	unsigned long addr, next;
+	int ret;
+
+	addr = start;
+	do {
+		p4d = p4d_offset(pgd, addr);
+
+		if (p4d_none(*p4d)) {
+			pud = pud_alloc_one(NULL, addr);
+			if (!pud) {
+				kvm_err("Cannot allocate Hyp pud\n");
+				return -ENOMEM;
+			}
+			kvm_p4d_populate(p4d, pud);
+			get_page(virt_to_page(p4d));
+		}
+
+		next = p4d_addr_end(addr, end);
+		ret = create_hyp_pud_mappings(p4d, addr, next, pfn, prot);
+		if (ret)
+			return ret;
+		pfn += (next - addr) >> PAGE_SHIFT;
+	} while (addr = next, addr != end);
+
+	return 0;
+}
+
 static int __create_hyp_mappings(pgd_t *pgdp, unsigned long ptrs_per_pgd,
 				 unsigned long start, unsigned long end,
 				 unsigned long pfn, pgprot_t prot)
 {
 	pgd_t *pgd;
-	pud_t *pud;
+	p4d_t *p4d;
 	unsigned long addr, next;
 	int err = 0;
 
@@ -705,18 +812,18 @@ static int __create_hyp_mappings(pgd_t *pgdp, unsigned long ptrs_per_pgd,
 		pgd = pgdp + kvm_pgd_index(addr, ptrs_per_pgd);
 
 		if (pgd_none(*pgd)) {
-			pud = pud_alloc_one(NULL, addr);
-			if (!pud) {
-				kvm_err("Cannot allocate Hyp pud\n");
+			p4d = p4d_alloc_one(NULL, addr);
+			if (!p4d) {
+				kvm_err("Cannot allocate Hyp p4d\n");
 				err = -ENOMEM;
 				goto out;
 			}
-			kvm_pgd_populate(pgd, pud);
+			kvm_pgd_populate(pgd, p4d);
 			get_page(virt_to_page(pgd));
 		}
 
 		next = pgd_addr_end(addr, end);
-		err = create_hyp_pud_mappings(pgd, addr, next, pfn, prot);
+		err = create_hyp_p4d_mappings(pgd, addr, next, pfn, prot);
 		if (err)
 			goto out;
 		pfn += (next - addr) >> PAGE_SHIFT;
@@ -1013,22 +1120,40 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
 		free_pages_exact(pgd, stage2_pgd_size(kvm));
 }
 
-static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+static p4d_t *stage2_get_p4d(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
 			     phys_addr_t addr)
 {
 	pgd_t *pgd;
-	pud_t *pud;
+	p4d_t *p4d;
 
 	pgd = kvm->arch.pgd + stage2_pgd_index(kvm, addr);
 	if (stage2_pgd_none(kvm, *pgd)) {
 		if (!cache)
 			return NULL;
-		pud = mmu_memory_cache_alloc(cache);
-		stage2_pgd_populate(kvm, pgd, pud);
+		p4d = mmu_memory_cache_alloc(cache);
+		stage2_pgd_populate(kvm, pgd, p4d);
 		get_page(virt_to_page(pgd));
 	}
 
-	return stage2_pud_offset(kvm, pgd, addr);
+	return stage2_p4d_offset(kvm, pgd, addr);
+}
+
+static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
+			     phys_addr_t addr)
+{
+	p4d_t *p4d;
+	pud_t *pud;
+
+	p4d = stage2_get_p4d(kvm, cache, addr);
+	if (stage2_p4d_none(kvm, *p4d)) {
+		if (!cache)
+			return NULL;
+		pud = mmu_memory_cache_alloc(cache);
+		stage2_p4d_populate(kvm, p4d, pud);
+		get_page(virt_to_page(p4d));
+	}
+
+	return stage2_pud_offset(kvm, p4d, addr);
 }
 
 static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
@@ -1468,18 +1593,18 @@ static void stage2_wp_pmds(struct kvm *kvm, pud_t *pud,
 }
 
 /**
- * stage2_wp_puds - write protect PGD range
+ * stage2_wp_puds - write protect P4D range
  * @pgd:	pointer to pgd entry
  * @addr:	range start address
  * @end:	range end address
  */
-static void  stage2_wp_puds(struct kvm *kvm, pgd_t *pgd,
+static void  stage2_wp_puds(struct kvm *kvm, p4d_t *p4d,
 			    phys_addr_t addr, phys_addr_t end)
 {
 	pud_t *pud;
 	phys_addr_t next;
 
-	pud = stage2_pud_offset(kvm, pgd, addr);
+	pud = stage2_pud_offset(kvm, p4d, addr);
 	do {
 		next = stage2_pud_addr_end(kvm, addr, end);
 		if (!stage2_pud_none(kvm, *pud)) {
@@ -1493,6 +1618,26 @@ static void  stage2_wp_puds(struct kvm *kvm, pgd_t *pgd,
 	} while (pud++, addr = next, addr != end);
 }
 
+/**
+ * stage2_wp_p4ds - write protect PGD range
+ * @pgd:	pointer to pgd entry
+ * @addr:	range start address
+ * @end:	range end address
+ */
+static void  stage2_wp_p4ds(struct kvm *kvm, pgd_t *pgd,
+			    phys_addr_t addr, phys_addr_t end)
+{
+	p4d_t *p4d;
+	phys_addr_t next;
+
+	p4d = stage2_p4d_offset(kvm, pgd, addr);
+	do {
+		next = stage2_p4d_addr_end(kvm, addr, end);
+		if (!stage2_p4d_none(kvm, *p4d))
+			stage2_wp_puds(kvm, p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+}
+
 /**
  * stage2_wp_range() - write protect stage2 memory region range
  * @kvm:	The KVM pointer
@@ -1520,7 +1665,7 @@ static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
 			break;
 		next = stage2_pgd_addr_end(kvm, addr, end);
 		if (stage2_pgd_present(kvm, *pgd))
-			stage2_wp_puds(kvm, pgd, addr, next);
+			stage2_wp_p4ds(kvm, pgd, addr, next);
 	} while (pgd++, addr = next, addr != end);
 }
 
-- 
2.24.0


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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Will Deacon]

On Mon, Jan 13, 2020 at 01:13:22PM +0200, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> This is a part of clean up of the page table manipulation code that aims to
> remove asm-generic/5level-fixup.h and asm-generic/pgtable-nop4d-hack.h
> 
> There is a single patch for both arm and arm64 because doing the conversion
> separately would mean breaking the shared mmu bits in virt/kvm/arm.

Unfortunately, that's going to be really hard to merge, as the two
architectures are maintained in different trees and the breadth of this
patch series is likely to lead to conflicts in both.

Will

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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Marc Zyngier]

On 2020-01-22 18:50, Will Deacon wrote:
> On Mon, Jan 13, 2020 at 01:13:22PM +0200, Mike Rapoport wrote:
>> From: Mike Rapoport <rppt@linux.ibm.com>
>> 
>> This is a part of clean up of the page table manipulation code that 
>> aims to
>> remove asm-generic/5level-fixup.h and asm-generic/pgtable-nop4d-hack.h
>> 
>> There is a single patch for both arm and arm64 because doing the 
>> conversion
>> separately would mean breaking the shared mmu bits in virt/kvm/arm.
> 
> Unfortunately, that's going to be really hard to merge, as the two
> architectures are maintained in different trees and the breadth of this
> patch series is likely to lead to conflicts in both.

But maybe this is the reason we've all been waiting for, for which we
sacrifice 32bit KVM host on the altar of progress, and finally move 
along.

Will and I are the only known users, and that'd be a good incentive to
experience some if this 64bit goodness... ;-)

         M.
-- 
Jazz is not dead. It just smells funny...

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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Mike Rapoport]

On Wed, Jan 22, 2020 at 06:50:17PM +0000, Will Deacon wrote:
> On Mon, Jan 13, 2020 at 01:13:22PM +0200, Mike Rapoport wrote:
> > From: Mike Rapoport <rppt@linux.ibm.com>
> > 
> > This is a part of clean up of the page table manipulation code that aims to
> > remove asm-generic/5level-fixup.h and asm-generic/pgtable-nop4d-hack.h
> > 
> > There is a single patch for both arm and arm64 because doing the conversion
> > separately would mean breaking the shared mmu bits in virt/kvm/arm.
> 
> Unfortunately, that's going to be really hard to merge, as the two
> architectures are maintained in different trees and the breadth of this
> patch series is likely to lead to conflicts in both.

I anyway realized that sending these changes arch-by-arch was not so bright
idea, so my intention is to make "v2" include all the changes required to
drop asm-generic/5level-fixup.h and merge it via the -mm tree.
 
> Will

-- 
Sincerely yours,
Mike.

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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Quentin Perret]

Hi Marc,

On Wednesday 22 Jan 2020 at 18:56:38 (+0000), Marc Zyngier wrote:
> But maybe this is the reason we've all been waiting for, for which we
> sacrifice 32bit KVM host on the altar of progress, and finally move along.
> 
> Will and I are the only known users, and that'd be a good incentive to
> experience some if this 64bit goodness... ;-)

Jumping in this discussion a bit randomly, but I just wanted to share
some thoughts that hopefully are relevant to this discussion and can be
of interest to the community.

Context: we have a use-case where guests would need some degree of memory
protection from the host for confidentiality reasons. We're currently
looking at extending KVM to support this feature by enabling the stage
2 translation for the host (in the NVHE case) so we can prevent it from
accessing private guest memory, in addition to many other changes
required to make this work properly. We're currently at the prototyping
stage, but hopefully we'll be able to share patches soon.

I'm bringing this up now because this particular use-case doesn't seem
relevant in the arm32 world -- all our potential users are on arm64.
However, because of the current structure of the arm/arm64 KVM host
code, making significant arm64-specific changes turns out to be really
hard.

We're currently left with three options:

  1. move code from virt/kvm/arm and duplicate it in the arch/arm and
     arch/arm64 folders so the arm64 version can diverge. I can imagine
     this duplication isn't exactly an appealing solution from a
     maintainer's perspective ...

  2. do changes in the virt/kvm/arm folder directly, but these must be
     met with matching changes in the respective arch/ folders. The
     code added to arch/arm, however, would be practically dead code,
     largely un-used and un-tested as there will be no real arm32 users
     of this feature.

  3. have lots of kvm_arm_* callbacks stubbed for arm32, but this tends
     to be really hard to apply to this use-case as some of the changes
     are really quite intrusive.

Obviously, details matter for all of this, and lots of discussions will
be needed once the patches are on the list.

But the point I'm trying to make here is the following: regardless of
the option we end up choosing (most likely a mix of all three), the sole
fact that we have to deal with this is clearly slowing down development
of the feature.

This would a be perfectly reasonable and acceptable overhead if this had
to be done to keep 32bit KVM host support for a real user community, but
since it doesn't seem to exist (?), fighting with the above options
feels like a lot of wasted efforts. (Note: I am not implying that Will
and you are not real persons, but well, you see what I mean ;-)).

So, this is the end of my daily rant. But hopefully this other example
of a real-world feature that's being held back by the 32bit KVM host
code will be useful background when/if we go ahead and finally decide
stop supporting it.

Thanks,
Quentin

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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Marc Zyngier]

Hi Quentin,

On 2020-01-24 12:20, Quentin Perret wrote:
> Hi Marc,
> 
> On Wednesday 22 Jan 2020 at 18:56:38 (+0000), Marc Zyngier wrote:
>> But maybe this is the reason we've all been waiting for, for which we
>> sacrifice 32bit KVM host on the altar of progress, and finally move 
>> along.
>> 
>> Will and I are the only known users, and that'd be a good incentive to
>> experience some if this 64bit goodness... ;-)

[future work for which 32bit support gets in the way]

> This would a be perfectly reasonable and acceptable overhead if this 
> had
> to be done to keep 32bit KVM host support for a real user community, 
> but
> since it doesn't seem to exist (?), fighting with the above options
> feels like a lot of wasted efforts. (Note: I am not implying that Will
> and you are not real persons, but well, you see what I mean ;-)).

I don't disagree at all. To be honest, I've been on the cusp of getting
rid of it for a while, for multiple reasons:

- It has no users (as you noticed)
- It is hardly tested (a consequence of the above)
- It isn't feature complete (no debug, no PMU)
- It doesn't follow any of the evolution of the architecture (a more
   generic feature of the 32bit port, probably because people run their
   64bit-capable cores in 64bit mode)
- It is becoming a mess of empty stubs

The maintenance aspect hasn't been a real problem so far. Even the NV
support is only about 200 lines of stubs. But what you have in mind is
going to be much more invasive, and I wouldn't want an unused feature to
get in the way.

What I may end-up doing is to send a RFC series to remove the 32bit host
support from the tree during in the 5.6 cycle, targeting 5.7. If someone
shouts loudly during that time frame, we keep it and you'll have to work
around it. If nobody cares, then dropping it is the right thing to do.

Would that be OK with you?

         M.
-- 
Jazz is not dead. It just smells funny...

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Re: [PATCH v2 0/1] arm/arm64: add support for folded p4d page tables

[Quentin Perret]

On Friday 24 Jan 2020 at 13:34:35 (+0000), Marc Zyngier wrote:
> I don't disagree at all. To be honest, I've been on the cusp of getting
> rid of it for a while, for multiple reasons:
> 
> - It has no users (as you noticed)
> - It is hardly tested (a consequence of the above)
> - It isn't feature complete (no debug, no PMU)
> - It doesn't follow any of the evolution of the architecture (a more
>   generic feature of the 32bit port, probably because people run their
>   64bit-capable cores in 64bit mode)
> - It is becoming a mess of empty stubs
> 
> The maintenance aspect hasn't been a real problem so far. Even the NV
> support is only about 200 lines of stubs. But what you have in mind is
> going to be much more invasive, and I wouldn't want an unused feature to
> get in the way.
> 
> What I may end-up doing is to send a RFC series to remove the 32bit host
> support from the tree during in the 5.6 cycle, targeting 5.7. If someone
> shouts loudly during that time frame, we keep it and you'll have to work
> around it. If nobody cares, then dropping it is the right thing to do.
> 
> Would that be OK with you?

Absolutely. And yes, if there are users of the 32 bits port, it'll be on
us to work around in a clean way, but I think this is perfectly fair.
I'll be happy to try and test your RFC series when it goes on the list
if that can help.

Thanks!
Quentin

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