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

Fuad Tabba
2026-03-11T10:16:18Z

On Thu, 5 Mar 2026 at 14:44, Will Deacon <will@kernel.org> wrote:
>
> 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>

Reviewed-by: Fuad Tabba <tabba@google.com>

Cheers,
/fuad

> ---
> 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
>