[PATCH V2] KVM: ARM: Remove pgtable page standard functions from stage-2 page tables

[Anshuman Khandual <anshuman.khandual@arm.com>]

ARM64 standard pgtable functions are going to use pgtable_page_[ctor|dtor]
or pgtable_pmd_page_[ctor|dtor] constructs. At present KVM guest stage-2
PUD|PMD|PTE level page tabe pages are allocated with __get_free_page()
via mmu_memory_cache_alloc() but released with standard pud|pmd_free() or
pte_free_kernel(). These will fail once they start calling into pgtable_
[pmd]_page_dtor() for pages which never originally went through respective
constructor functions. Hence convert all stage-2 page table page release
functions to call buddy directly while freeing pages.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
Changes in V2:

- Updated stage2_pud_free() with NOP as per Suzuki
- s/__free_page/free_page/ in clear_stage2_pmd_entry() for uniformity

 arch/arm/include/asm/stage2_pgtable.h   | 4 ++--
 arch/arm64/include/asm/stage2_pgtable.h | 4 ++--
 virt/kvm/arm/mmu.c                      | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/stage2_pgtable.h b/arch/arm/include/asm/stage2_pgtable.h
index de2089501b8b..fed02c3b4600 100644
--- a/arch/arm/include/asm/stage2_pgtable.h
+++ b/arch/arm/include/asm/stage2_pgtable.h
@@ -32,14 +32,14 @@
 #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_pud_free(kvm, pud)		pud_free(NULL, pud)
+#define stage2_pud_free(kvm, pud)		do { } while (0)
 
 #define stage2_pud_none(kvm, pud)		pud_none(pud)
 #define stage2_pud_clear(kvm, pud)		pud_clear(pud)
 #define stage2_pud_present(kvm, pud)		pud_present(pud)
 #define stage2_pud_populate(kvm, pud, pmd)	pud_populate(NULL, pud, pmd)
 #define stage2_pmd_offset(kvm, pud, address)	pmd_offset(pud, address)
-#define stage2_pmd_free(kvm, pmd)		pmd_free(NULL, pmd)
+#define stage2_pmd_free(kvm, pmd)		free_page((unsigned long)pmd)
 
 #define stage2_pud_huge(kvm, pud)		pud_huge(pud)
 
diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h
index 5412fa40825e..915809e4ac32 100644
--- a/arch/arm64/include/asm/stage2_pgtable.h
+++ b/arch/arm64/include/asm/stage2_pgtable.h
@@ -119,7 +119,7 @@ static inline pud_t *stage2_pud_offset(struct kvm *kvm,
 static inline void stage2_pud_free(struct kvm *kvm, pud_t *pud)
 {
 	if (kvm_stage2_has_pud(kvm))
-		pud_free(NULL, pud);
+		free_page((unsigned long)pud);
 }
 
 static inline bool stage2_pud_table_empty(struct kvm *kvm, pud_t *pudp)
@@ -192,7 +192,7 @@ static inline pmd_t *stage2_pmd_offset(struct kvm *kvm,
 static inline void stage2_pmd_free(struct kvm *kvm, pmd_t *pmd)
 {
 	if (kvm_stage2_has_pmd(kvm))
-		pmd_free(NULL, pmd);
+		free_page((unsigned long)pmd);
 }
 
 static inline bool stage2_pud_huge(struct kvm *kvm, pud_t pud)
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index e9d28a7ca673..cbfbdadca8a5 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -191,7 +191,7 @@ static void clear_stage2_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr
 	VM_BUG_ON(pmd_thp_or_huge(*pmd));
 	pmd_clear(pmd);
 	kvm_tlb_flush_vmid_ipa(kvm, addr);
-	pte_free_kernel(NULL, pte_table);
+	free_page((unsigned long)pte_table);
 	put_page(virt_to_page(pmd));
 }
 
-- 
2.20.1