> so it's much more feasible for someone to consider the latter
And conversely it's much more beneficial for an attacker to consider the former (attacking the hypervisor), this exacerbates the situation by making red team more aggressive to one side whilst blue team is busy debating if they should disable SMT .
I mean, that's always possible but it was always the case that the blue team needs to worry about the entire stack and one of those two choices has several orders of magnitude more work involved. The blue team could disable SMT and switch back to debating Xen with almost no discernible impact on the time needed for the latter and an entire branch of the threat tree removed.
And conversely it's much more beneficial for an attacker to consider the former (attacking the hypervisor), this exacerbates the situation by making red team more aggressive to one side whilst blue team is busy debating if they should disable SMT .