Re: [PATCH v2 05/39] xen/riscv: request a G-stage flush on vmenter when VMIDs are disabled

[Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>]

> vmid_handle_vmenter() reports that no flush is needed when VMIDs are
> unavailable (vmid=off, or hardware with no more than one VMID bit). Every
> domain then runs under VMID 0 with nothing flushed in between, so as soon
> as a hart runs more than one domain, a domain entered there can use the
> G-stage translations left behind by the domain which ran before it.
> 
> Adjust the comment in p2m_handle_vmenter() accordingly: skipping the
> VS-stage flush no longer relies on an old VMID not being reused, which
> doesn't hold when there are no VMIDs to begin with.
> 
> While at it, spell the other early return as a bool literal.
> 
> Fixes: bff3b9ea4696 ("xen/riscv: introduce VMID allocation and manegement")
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>

FWIW this comment and p2m_handle_vmenter() itself get dropped a few
patches later in "implement vCPU context switching", which folds the
VMID claim into p2m_ctxt_switch_to(). The fix survives there via the
need_flush check. Is this patch really needed?

-- 
Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>