On 10/5/24 1:27 AM, Steven Price wrote:
From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Keep track of the number of pages allocated for the top level PGD,
rather than computing it every time (though we need it only twice now).
This will be used later by Arm CCA KVM changes.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
arch/arm64/include/asm/kvm_pgtable.h | 2 ++
arch/arm64/kvm/hyp/pgtable.c | 5 +++--
2 files changed, 5 insertions(+), 2 deletions(-)
If we really want to have the number of pages for the top level PGDs,
the existing helpers kvm_pgtable_stage2_pgd_size() for the same purpose
needs to replaced by (struct kvm_pgtable::pgd_pages << PAGE_SHIFT) and
then removed.
The alternative would be just to use kvm_pgtable_stage2_pgd_size() instead of
introducing struct kvm_pgtable::pgd_pages, which will be used in the slow
paths where realm is created or destroyed.
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 03f4c3d7839c..25b512756200 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -404,6 +404,7 @@ 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.
@@ -414,6 +415,7 @@ 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 b11bcebac908..9e1be28c3dc9 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1534,7 +1534,8 @@ 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;
@@ -1586,7 +1587,7 @@ 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;
}
Thanks,
Gavin
