[PATCH v2 3/5] KVM: arm64: mm: count KVM page table pages in pagetable stats
From: Yosry Ahmed
Date: Mon Apr 04 2022 - 19:42:42 EST
Count the pages used by KVM in arm64 for page tables in pagetable stats.
Account pages allocated for PTEs in pgtable init functions and
kvm_set_table_pte().
Since most page table pages are freed using put_page(), add a helper
function put_pte_page() that checks if this is the last ref for a pte
page before putting it, and unaccounts stats accordingly.
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
arch/arm64/kernel/image-vars.h | 3 ++
arch/arm64/kvm/hyp/pgtable.c | 50 +++++++++++++++++++++-------------
2 files changed, 34 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 884844849c70..4c87a718ccf0 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -139,6 +139,9 @@ KVM_NVHE_ALIAS(__hyp_rodata_end);
/* pKVM static key */
KVM_NVHE_ALIAS(kvm_protected_mode_initialized);
+/* Called by kvm_account_pgtable_pages() to update pagetable stats */
+KVM_NVHE_ALIAS(__mod_lruvec_page_state);
+
#endif /* CONFIG_KVM */
#endif /* __ARM64_KERNEL_IMAGE_VARS_H */
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 2cb3867eb7c2..53e13c3313e9 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -152,6 +152,7 @@ static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp,
WARN_ON(kvm_pte_valid(old));
smp_store_release(ptep, pte);
+ kvm_account_pgtable_pages((void *)childp, +1);
}
static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
@@ -326,6 +327,14 @@ int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
return ret;
}
+static void put_pte_page(kvm_pte_t *ptep, struct kvm_pgtable_mm_ops *mm_ops)
+{
+ /* If this is the last page ref, decrement pagetable stats first. */
+ if (!mm_ops->page_count || mm_ops->page_count(ptep) == 1)
+ kvm_account_pgtable_pages((void *)ptep, -1);
+ mm_ops->put_page(ptep);
+}
+
struct hyp_map_data {
u64 phys;
kvm_pte_t attr;
@@ -488,10 +497,10 @@ static int hyp_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
dsb(ish);
isb();
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
if (childp)
- mm_ops->put_page(childp);
+ put_pte_page(childp, mm_ops);
return 0;
}
@@ -522,6 +531,7 @@ int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
pgt->pgd = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
if (!pgt->pgd)
return -ENOMEM;
+ kvm_account_pgtable_pages((void *)pgt->pgd, +1);
pgt->ia_bits = va_bits;
pgt->start_level = KVM_PGTABLE_MAX_LEVELS - levels;
@@ -541,10 +551,10 @@ static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (!kvm_pte_valid(pte))
return 0;
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
if (kvm_pte_table(pte, level))
- mm_ops->put_page(kvm_pte_follow(pte, mm_ops));
+ put_pte_page(kvm_pte_follow(pte, mm_ops), mm_ops);
return 0;
}
@@ -558,7 +568,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
};
WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
- pgt->mm_ops->put_page(pgt->pgd);
+ put_pte_page(pgt->pgd, pgt->mm_ops);
pgt->pgd = NULL;
}
@@ -694,7 +704,7 @@ static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr,
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, addr, level);
}
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
}
static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
@@ -795,7 +805,7 @@ static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (data->anchor) {
if (stage2_pte_is_counted(pte))
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
return 0;
}
@@ -848,8 +858,8 @@ static int stage2_map_walk_table_post(u64 addr, u64 end, u32 level,
childp = kvm_pte_follow(*ptep, mm_ops);
}
- mm_ops->put_page(childp);
- mm_ops->put_page(ptep);
+ put_pte_page(childp, mm_ops);
+ put_pte_page(ptep, mm_ops);
return ret;
}
@@ -962,7 +972,7 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (!kvm_pte_valid(pte)) {
if (stage2_pte_is_counted(pte)) {
kvm_clear_pte(ptep);
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
}
return 0;
}
@@ -988,7 +998,7 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
kvm_granule_size(level));
if (childp)
- mm_ops->put_page(childp);
+ put_pte_page(childp, mm_ops);
return 0;
}
@@ -1177,16 +1187,17 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
enum kvm_pgtable_stage2_flags flags,
kvm_pgtable_force_pte_cb_t force_pte_cb)
{
- size_t pgd_sz;
+ u32 pgd_num;
u64 vtcr = mmu->arch->vtcr;
u32 ia_bits = VTCR_EL2_IPA(vtcr);
u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
- pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
- pgt->pgd = mm_ops->zalloc_pages_exact(pgd_sz);
+ pgd_num = kvm_pgd_pages(ia_bits, start_level);
+ pgt->pgd = mm_ops->zalloc_pages_exact(pgd_num * PAGE_SIZE);
if (!pgt->pgd)
return -ENOMEM;
+ kvm_account_pgtable_pages((void *)pgt->pgd, +pgd_num);
pgt->ia_bits = ia_bits;
pgt->start_level = start_level;
@@ -1210,17 +1221,17 @@ static int stage2_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (!stage2_pte_is_counted(pte))
return 0;
- mm_ops->put_page(ptep);
+ put_pte_page(ptep, mm_ops);
if (kvm_pte_table(pte, level))
- mm_ops->put_page(kvm_pte_follow(pte, mm_ops));
+ put_pte_page(kvm_pte_follow(pte, mm_ops), mm_ops);
return 0;
}
void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
{
- size_t pgd_sz;
+ u32 pgd_num;
struct kvm_pgtable_walker walker = {
.cb = stage2_free_walker,
.flags = KVM_PGTABLE_WALK_LEAF |
@@ -1229,7 +1240,8 @@ 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;
- pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz);
+ pgd_num = kvm_pgd_pages(pgt->ia_bits, pgt->start_level);
+ kvm_account_pgtable_pages((void *)pgt->pgd, -pgd_num);
+ pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_num * PAGE_SIZE);
pgt->pgd = NULL;
}
--
2.35.1.1094.g7c7d902a7c-goog