[PATCH v3 21/36] KVM: arm64: Introduce host_stage2_set_owner_metadata_locked()

Will Deacon
2026-03-05T14:45:23Z

Rework host_stage2_set_owner_locked() to add a new helper function,
host_stage2_set_owner_metadata_locked(), which will allow us to store
additional metadata alongside a 3-bit owner ID for invalid host stage-2
entries.

Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/kvm_pgtable.h | 2 --
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 47 ++++++++++++++++++---------
2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index e36c2908bdb2..2df22640833c 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -99,8 +99,6 @@ 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)
-
/* pKVM invalid pte encodings */
#define KVM_INVALID_PTE_TYPE_MASK GENMASK(63, 60)
#define KVM_INVALID_PTE_ANNOT_MASK ~(KVM_PTE_VALID | \
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index b4c2ca86e5b3..ed540ccd1595 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -549,37 +549,54 @@ 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)
+#define KVM_HOST_DONATION_PTE_OWNER_MASK GENMASK(3, 1)
+#define KVM_HOST_DONATION_PTE_EXTRA_MASK GENMASK(59, 4)
+static int host_stage2_set_owner_metadata_locked(phys_addr_t addr, u64 size,
+ u8 owner_id, u64 meta)
{
kvm_pte_t annotation;
- int ret = -EINVAL;
+ int ret;

- if (!FIELD_FIT(KVM_INVALID_PTE_OWNER_MASK, owner_id))
+ if (owner_id == PKVM_ID_HOST)
return -EINVAL;

if (!range_is_memory(addr, addr + size))
return -EPERM;

+ if (!FIELD_FIT(KVM_HOST_DONATION_PTE_OWNER_MASK, owner_id))
+ return -EINVAL;
+
+ if (!FIELD_FIT(KVM_HOST_DONATION_PTE_EXTRA_MASK, meta))
+ return -EINVAL;
+
+ annotation = FIELD_PREP(KVM_HOST_DONATION_PTE_OWNER_MASK, owner_id) |
+ FIELD_PREP(KVM_HOST_DONATION_PTE_EXTRA_MASK, meta);
+ ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
+ addr, size, &host_s2_pool,
+ KVM_HOST_INVALID_PTE_TYPE_DONATION, annotation);
+ if (!ret)
+ __host_update_page_state(addr, size, PKVM_NOPAGE);
+
+ return ret;
+}
+
+int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
+{
+ int ret = -EINVAL;
+
switch (owner_id) {
case PKVM_ID_HOST:
+ if (!range_is_memory(addr, addr + size))
+ return -EPERM;
+
ret = host_stage2_idmap_locked(addr, size, PKVM_HOST_MEM_PROT);
if (!ret)
__host_update_page_state(addr, size, PKVM_PAGE_OWNED);
break;
case PKVM_ID_GUEST:
case PKVM_ID_HYP:
- annotation = kvm_init_invalid_leaf_owner(owner_id);
- ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
- addr, size, &host_s2_pool,
- KVM_HOST_INVALID_PTE_TYPE_DONATION,
- annotation);
- if (!ret)
- __host_update_page_state(addr, size, PKVM_NOPAGE);
+ ret = host_stage2_set_owner_metadata_locked(addr, size,
+ owner_id, 0);
break;
}

--
2.53.0.473.g4a7958ca14-goog