[PATCH 17/30] KVM: arm64: Generalise kvm_pgtable_stage2_set_owner()
Will Deacon
will at kernel.org
Mon Jan 5 07:49:25 PST 2026
kvm_pgtable_stage2_set_owner() can be generalised into a way to store
up to 62 bits in the page tables, as long as we don't set the 'valid' or
KVM_INVALID_PTE_LOCKED bits.
Let's do that and reduce the owner field to 4 bits to free up more
annotation space for future work.
Signed-off-by: Will Deacon <will at kernel.org>
---
arch/arm64/include/asm/kvm_pgtable.h | 21 +++++++++++++--------
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 14 ++++++++++++--
arch/arm64/kvm/hyp/pgtable.c | 17 ++++++-----------
3 files changed, 31 insertions(+), 21 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 9ce55442b621..ddbe0e506e4c 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -97,14 +97,17 @@ typedef u64 kvm_pte_t;
KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \
KVM_PTE_LEAF_ATTR_HI_S2_XN)
-#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2)
-#define KVM_MAX_OWNER_ID 3
+/* pKVM invalid pte encodings */
+#define KVM_INVALID_PTE_OWNER_MASK GENMASK(4, 1)
+#define KVM_INVALID_PTE_EXTRA_MASK GENMASK(62, 5)
+#define KVM_INVALID_PTE_ANNOT_MASK (KVM_INVALID_PTE_OWNER_MASK | \
+ KVM_INVALID_PTE_EXTRA_MASK)
/*
* Used to indicate a pte for which a 'break-before-make' sequence is in
* progress.
*/
-#define KVM_INVALID_PTE_LOCKED BIT(10)
+#define KVM_INVALID_PTE_LOCKED BIT(63)
static inline bool kvm_pte_valid(kvm_pte_t pte)
{
@@ -657,14 +660,16 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
void *mc, enum kvm_pgtable_walk_flags flags);
/**
- * kvm_pgtable_stage2_set_owner() - Unmap and annotate pages in the IPA space to
- * track ownership.
+ * kvm_pgtable_stage2_annotate() - Unmap and annotate pages in the IPA space
+ * to track ownership (and more).
* @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*().
* @addr: Base intermediate physical address to annotate.
* @size: Size of the annotated range.
* @mc: Cache of pre-allocated and zeroed memory from which to allocate
* page-table pages.
- * @owner_id: Unique identifier for the owner of the page.
+ * @annotation: A 62-bit value that will be stored in the page tables.
+ * @annotation[0] and @annotation[63] must be 0.
+ * @annotation[62:1] is stored in the page tables.
*
* By default, all page-tables are owned by identifier 0. This function can be
* used to mark portions of the IPA space as owned by other entities. When a
@@ -673,8 +678,8 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
*
* Return: 0 on success, negative error code on failure.
*/
-int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
- void *mc, u8 owner_id);
+int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
+ void *mc, kvm_pte_t annotation);
/**
* kvm_pgtable_stage2_unmap() - Remove a mapping from a guest stage-2 page-table.
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 0336143cbb24..6c32bdc689ed 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -539,15 +539,25 @@ static void __host_update_page_state(phys_addr_t addr, u64 size, enum pkvm_page_
set_host_state(page, state);
}
+static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
+{
+ return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
+}
+
int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
{
+ kvm_pte_t annotation;
int ret;
+ if (!FIELD_FIT(KVM_INVALID_PTE_OWNER_MASK, owner_id))
+ return -EINVAL;
+
if (!range_is_memory(addr, addr + size))
return -EPERM;
- ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_mmu.pgt,
- addr, size, &host_s2_pool, owner_id);
+ annotation = kvm_init_invalid_leaf_owner(owner_id);
+ ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
+ addr, size, &host_s2_pool, annotation);
if (ret)
return ret;
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 9abc0a6cf448..749ee5863601 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -114,11 +114,6 @@ static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, s8 level)
return pte;
}
-static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
-{
- return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
-}
-
static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data,
const struct kvm_pgtable_visit_ctx *ctx,
enum kvm_pgtable_walk_flags visit)
@@ -563,7 +558,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
struct stage2_map_data {
const u64 phys;
kvm_pte_t attr;
- u8 owner_id;
+ kvm_pte_t pte_annot;
kvm_pte_t *anchor;
kvm_pte_t *childp;
@@ -946,7 +941,7 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
if (!data->annotation)
new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
else
- new = kvm_init_invalid_leaf_owner(data->owner_id);
+ new = data->pte_annot;
/*
* Skip updating the PTE if we are trying to recreate the exact
@@ -1100,16 +1095,16 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
return ret;
}
-int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
- void *mc, u8 owner_id)
+int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
+ void *mc, kvm_pte_t pte_annot)
{
int ret;
struct stage2_map_data map_data = {
.mmu = pgt->mmu,
.memcache = mc,
- .owner_id = owner_id,
.force_pte = true,
.annotation = true,
+ .pte_annot = pte_annot,
};
struct kvm_pgtable_walker walker = {
.cb = stage2_map_walker,
@@ -1118,7 +1113,7 @@ int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
.arg = &map_data,
};
- if (owner_id > KVM_MAX_OWNER_ID)
+ if (pte_annot & ~KVM_INVALID_PTE_ANNOT_MASK)
return -EINVAL;
ret = kvm_pgtable_walk(pgt, addr, size, &walker);
--
2.52.0.351.gbe84eed79e-goog
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