[v3,02/43] kvm: arm64: pgtable: Track the number of pages in the entry level

Commit Message

Steven Price June 10, 2024, 1:41 p.m. UTC

From: Suzuki K Poulose <[e-mail]>

Keep track of the number of pages allocated for the top level PGD,
rather than computing it everytime (though we need it only twice now).
This will be used later by Arm CCA KVM changes.

Signed-off-by: Suzuki K Poulose <[e-mail]>
Signed-off-by: Steven Price <[e-mail]>
---
 arch/arm64/include/asm/kvm_pgtable.h | 2 ++
 arch/arm64/kvm/hyp/pgtable.c         | 5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

Patch

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 19278dfe7978..0350c08ada7a 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -362,6 +362,7 @@  static inline bool kvm_pgtable_walk_lock_held(void)
  * struct kvm_pgtable - KVM page-table.
  * @ia_bits:		Maximum input address size, in bits.
  * @start_level:	Level at which the page-table walk starts.
+ * @pgd_pages:		Number of pages in the entry level of the page-table.
  * @pgd:		Pointer to the first top-level entry of the page-table.
  * @mm_ops:		Memory management callbacks.
  * @mmu:		Stage-2 KVM MMU struct. Unused for stage-1 page-tables.
@@ -372,6 +373,7 @@  static inline bool kvm_pgtable_walk_lock_held(void)
 struct kvm_pgtable {
 	u32					ia_bits;
 	s8					start_level;
+	u8					pgd_pages;
 	kvm_pteref_t				pgd;
 	struct kvm_pgtable_mm_ops		*mm_ops;
 
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 9e2bbee77491..fb6675838b65 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1574,7 +1574,8 @@  int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
 	u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
 	s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
 
-	pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
+	pgt->pgd_pages = kvm_pgd_pages(ia_bits, start_level);
+	pgd_sz = pgt->pgd_pages * PAGE_SIZE;
 	pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz);
 	if (!pgt->pgd)
 		return -ENOMEM;
@@ -1626,7 +1627,7 @@  void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
 	};
 
 	WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
-	pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
+	pgd_sz = pgt->pgd_pages * PAGE_SIZE;
 	pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz);
 	pgt->pgd = NULL;
 }