Re: [PATCH] target/ppc: Fix regression in Radix MMU

[Víctor Colombo]

On 28/10/2022 15:36, Leandro Lupori wrote:
> Commit 47e83d9107 ended up unintentionally changing the control flow
> of ppc_radix64_process_scoped_xlate(). When guest_visible is false,
> it must not raise an exception, even if the radix configuration is
> not valid.
>
> This regression prevented Linux boot in a nested environment with
> L1 using TCG and emulating KVM (cap-nested-hv=on) and L2 using
> KVM. L2 would hang on Linux's futex_init(), when it tested how a
> futex_atomic_cmpxchg_inatomic() handled a fault, because L1 would
> start a loop of trying to perform partition scoped translations
> and raising exceptions.
>
> Fixes: 47e83d9107 ("target/ppc: Improve Radix xlate level validation")
> Reported-by: Victor Colombo <victor.colombo@eldorado.org.br>
> Signed-off-by: Leandro Lupori <leandro.lupori@eldorado.org.br>

It now reaches the login screen on L2

Tested-by: Víctor Colombo <victor.colombo@eldorado.org.br>

--
Víctor Cora Colombo
Instituto de Pesquisas ELDORADO
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