Populate bits [56:55] of the leaf entry with the level provided
by the guest's S2 translation.

Signed-off-by: Marc Zyngier <m...@kernel.org>
---
 arch/arm64/include/asm/kvm_nested.h | 8 ++++++++
 arch/arm64/kvm/mmu.c                | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_nested.h 
b/arch/arm64/include/asm/kvm_nested.h
index 34499c496ae6..76fbf5de1f2c 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -5,6 +5,8 @@
 #include <linux/bitfield.h>
 #include <linux/kvm_host.h>
 
+#include <asm/kvm_pgtable.h>
+
 static inline bool nested_virt_in_use(const struct kvm_vcpu *vcpu)
 {
        return (!__is_defined(__KVM_NVHE_HYPERVISOR__) &&
@@ -135,4 +137,10 @@ void access_nested_id_reg(struct kvm_vcpu *v, struct 
sys_reg_params *p,
 
 #define KVM_NV_GUEST_MAP_SZ    GENMASK_ULL(56, 55)
 
+static inline u64 kvm_encode_nested_level(struct kvm_s2_trans *trans)
+{
+       return FIELD_PREP(KVM_PGTABLE_PROT_SW1 | KVM_PGTABLE_PROT_SW0,
+                         trans->level);
+}
+
 #endif /* __ARM64_KVM_NESTED_H */
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 7e640cae732d..388a6d25bf34 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1157,11 +1157,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, 
phys_addr_t fault_ipa,
         * Potentially reduce shadow S2 permissions to match the guest's own
         * S2. For exec faults, we'd only reach this point if the guest
         * actually allowed it (see kvm_s2_handle_perm_fault).
+        *
+        * Also encode the level of the nested translation in the SW bits of
+        * the PTE/PMD/PUD. This will be retrived on TLB invalidation from
+        * the guest.
         */
        if (kvm_is_shadow_s2_fault(vcpu)) {
                writable &= kvm_s2_trans_writable(nested);
                if (!kvm_s2_trans_readable(nested))
                        prot &= ~KVM_PGTABLE_PROT_R;
+
+               prot |= kvm_encode_nested_level(nested);
        }
 
        spin_lock(&kvm->mmu_lock);
-- 
2.30.2

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