Introduce helper functions in the KVM stage-2 and stage-1 page-table
manipulation library allowing to retrieve the enum kvm_pgtable_prot of a
PTE. This will be useful to implement custom walkers outside of
pgtable.c.
Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_pgtable.h | 20 ++++++++++++
arch/arm64/kvm/hyp/pgtable.c | 49 ++++++++++++++++++++++++++++
2 files changed, 69 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index f6d3d5c8910d..1aa49d6aabb7 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -467,4 +467,24 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
*/
int kvm_pgtable_stage2_find_range(struct kvm_pgtable *pgt, u64 addr,
int owner, struct kvm_mem_range *range);
+
+/**
+ * kvm_pgtable_stage2_pte_prot() - Retrieve the protection attributes of a
+ * stage-2 Page-Table Entry.
+ * @pte: Page-table entry
+ *
+ * Return: protection attributes of the page-table entry in the enum
+ * kvm_pgtable_prot format.
+ */
+enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
+
+/**
+ * kvm_pgtable_hyp_pte_prot() - Retrieve the protection attributes of a stage-1
+ * Page-Table Entry.
+ * @pte: Page-table entry
+ *
+ * Return: protection attributes of the page-table entry in the enum
+ * kvm_pgtable_prot format.
+ */
+enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
#endif /* __ARM64_KVM_PGTABLE_H__ */
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 51598b79dafc..c7120797404a 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -234,6 +234,20 @@ static kvm_pte_t pte_ignored_bit_prot(enum kvm_pgtable_prot prot)
return FIELD_PREP(KVM_PTE_LEAF_ATTR_IGNORED, ignored_bits);
}
+static enum kvm_pgtable_prot pte_read_ignored_bits_prot(kvm_pte_t pte)
+{
+ enum kvm_pgtable_prot prot = 0;
+ kvm_pte_t ignored_bits = 0;
+
+ ignored_bits = FIELD_GET(KVM_PTE_LEAF_ATTR_IGNORED, pte);
+ if (ignored_bits & BIT(1))
+ prot |= KVM_PGTABLE_STATE_BORROWED | KVM_PGTABLE_STATE_SHARED;
+ if (ignored_bits & BIT(0))
+ prot |= KVM_PGTABLE_STATE_SHARED;
+
+ return prot;
+}
+
static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr,
u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag)
@@ -386,6 +400,25 @@ static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
return 0;
}
+enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
+{
+ enum kvm_pgtable_prot prot = 0;
+ u32 ap;
+
+ if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN))
+ prot |= KVM_PGTABLE_PROT_X;
+
+ ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte);
+ if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO)
+ prot |= KVM_PGTABLE_PROT_R;
+ else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW)
+ prot |= KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W;
+
+ prot |= pte_read_ignored_bits_prot(pte);
+
+ return prot;
+}
+
static bool hyp_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
{
if (old == new)
@@ -588,6 +621,22 @@ static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot p
return 0;
}
+enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
+{
+ enum kvm_pgtable_prot prot = 0;
+
+ if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
+ prot |= KVM_PGTABLE_PROT_R;
+ if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
+ prot |= KVM_PGTABLE_PROT_W;
+ if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
+ prot |= KVM_PGTABLE_PROT_X;
+
+ prot |= pte_read_ignored_bits_prot(pte);
+
+ return prot;
+}
+
static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
{
if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
--
2.32.0.402.g57bb445576-goog
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