[PATCH v3 02/36] KVM: arm64: Move handle check into pkvm_pgtable_stage2_destroy_range()

[Will Deacon <will@kernel.org>]

When pKVM is enabled, a VM has a 'handle' allocated by the hypervisor
in kvm_arch_init_vm() and released later by kvm_arch_destroy_vm().

Consequently, the only time __pkvm_pgtable_stage2_unmap() can run into
an uninitialised 'handle' is on the kvm_arch_init_vm() failure path,
where we destroy the empty stage-2 page-table if we fail to allocate a
handle.

Move the handle check into pkvm_pgtable_stage2_destroy_range(), which
will additionally handle protected VMs in subsequent patches.

Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/pkvm.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index d7a0f69a9982..7797813f4dbe 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -329,9 +329,6 @@ static int __pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 start, u64 e
 	struct pkvm_mapping *mapping;
 	int ret;
 
-	if (!handle)
-		return 0;
-
 	for_each_mapping_in_range_safe(pgt, start, end, mapping) {
 		ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn,
 					mapping->nr_pages);
@@ -347,6 +344,12 @@ static int __pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 start, u64 e
 void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
 					u64 addr, u64 size)
 {
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+
+	if (!handle)
+		return;
+
 	__pkvm_pgtable_stage2_unmap(pgt, addr, addr + size);
 }
 
-- 
2.53.0.473.g4a7958ca14-goog