Re: [PATCH v3 01/17] KVM: arm64: Add pkvm_private_va_range_pa

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Incorrect physical address calculation for block mappings in pkvm_private_va_range_pa()
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--- Patch [1]: [PATCH v3 01/17] KVM: arm64: Add pkvm_private_va_range_pa ---
commit 81aa726ac7516be8619c0cb2674493e48b6fca16
Author: Vincent Donnefort <vdonnefort@google.com>

KVM: arm64: Add pkvm_private_va_range_pa

This commit introduces pkvm_private_va_range_pa() to resolve physical
addresses for the pKVM private range by walking the hypervisor page-table.
This prepares for the upcoming pKVM heap allocator.

> diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
> --- a/arch/arm64/kvm/hyp/nvhe/mm.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mm.c
[ ... ]
> +phys_addr_t pkvm_private_va_range_pa(void *va)
> +{
> +	kvm_pte_t pte = 0;
> +
> +	guard(hyp_spinlock)(&pkvm_pgd_lock);
> +	WARN_ON(kvm_pgtable_get_leaf(&pkvm_pgtable, (u64)va, &pte, NULL));
> +	WARN_ON(!kvm_pte_valid(pte));
> +
> +	return kvm_pte_to_phys(pte) + offset_in_page(va);

[Severity: High]
Does this calculation handle block mappings correctly?

If the virtual address is mapped via a block descriptor (such as a 2MB
large page), kvm_pte_to_phys(pte) returns the base physical address of
the block. Adding offset_in_page(va) will only preserve the lowest 12
bits, discarding the intermediate offset bits between the page size and
the block size.

Could this cause multiple virtual pages within the block mapping to
incorrectly resolve to the same physical base page plus a small offset?
Perhaps this should retrieve the mapping level from kvm_pgtable_get_leaf()
and mask the virtual address with the corresponding granule size?

> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260720171513.1415357-1-vdonnefort@google.com?part=1