target/arm: Limit LPA2 effective output address when TCR.DS == 0

target/arm: Limit LPA2 effective output address when TCR.DS == 0

With LPA2, the effective output address size is at most 48 bits when
TCR.DS == 0. This case is currently unhandled in the page table walker,
where we happily assume LVA/64k granule when outputsize > 48 and
param.ds == 0, resulting in the wrong conversion to be used from a
page table descriptor to a physical address.

    if (outputsize > 48) {
        if (param.ds) {
            descaddr |= extract64(descriptor, 8, 2) << 50;
        } else {
            descaddr |= extract64(descriptor, 12, 4) << 48;
        }

So cap the outputsize to 48 when TCR.DS is cleared, as per the
architecture.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20221116170316.259695-1-ardb@kernel.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>