• Marc Zyngier's avatar
    KVM: arm/arm64: Move HYP IO VAs to the "idmap" range · e3f019b3
    Marc Zyngier authored
    We so far mapped our HYP IO (which is essentially the GICv2 control
    registers) using the same method as for memory. It recently appeared
    that is a bit unsafe:
    
    We compute the HYP VA using the kern_hyp_va helper, but that helper
    is only designed to deal with kernel VAs coming from the linear map,
    and not from the vmalloc region... This could in turn cause some bad
    aliasing between the two, amplified by the upcoming VA randomisation.
    
    A solution is to come up with our very own basic VA allocator for
    MMIO. Since half of the HYP address space only contains a single
    page (the idmap), we have plenty to borrow from. Let's use the idmap
    as a base, and allocate downwards from it. GICv2 now lives on the
    other side of the great VA barrier.
    Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
    e3f019b3
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