Re: [PATCH] KVM: arm64: Implement KVM_TRANSLATE ioctl for arm64

[Priscilla Lam]

On 9/23/25, 2:26 AM, "Marc Zyngier" <maz@xxxxxxxxxx> wrote:
> A guest doing this is a sure indication that it is completely broken,
> and will fail on actual HW, because it clearly ignores small
> insignificant details such as *ordering*.
> 
> My other question still remains: why can't you perform this page table
> walk in userspace? It is actually much safer to do so because you can
> stop other vcpus while inspecting the PTs, and avoid a vcpu playing
> tricks behind your back -- something the in-kernel PTW doesn't try to
> avoid.

In our case, this comes from the Windows TPM driver using ldp32 to read
static adjacent CRB fields where ordering doesn't matter, but I agree 
that a guest relying on this kind of translation is problematic. We'll
drop this KVM_TRANSLATE implementation and pursue a different approach
instead.

Thanks,
Priscilla