[PATCH] arm64: Clear VTCR_EL2 in __init_el2_stage2()
Marc Zyngier
maz at kernel.org
Fri Mar 13 00:25:55 PDT 2026
On Fri, 13 Mar 2026 05:38:57 +0000,
Anshuman Khandual <anshuman.khandual at arm.com> wrote:
>
> Clear VTCR_EL2 along with VTTBR_EL2 register in __init_el2_stage2(), which
> ensures that MMU stage-2 translation remain disabled. Although clearing out
> VTTBR_EL2 probably should have been sufficient but adding VTCR_EL2 improves
> overall safety.
This serves no purpose whatsoever. Even the write to VTTBR_EL2 is
pointless, and writing 0 is no better than writing *any* other value.
The only thing that matters at this stage is HCR_EL2.VM, which
actually controls stage-2 translation (contrary to your above
assertion). This of course is not captured by this macro.
So what are you *really* trying to achieve?
Thanks,
M.
--
Jazz isn't dead. It just smells funny.
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