• Robin Murphy's avatar
    iommu: Disambiguate MSI region types · 9d3a4de4
    Robin Murphy authored
    The introduction of reserved regions has left a couple of rough edges
    which we could do with sorting out sooner rather than later. Since we
    are not yet addressing the potential dynamic aspect of software-managed
    reservations and presenting them at arbitrary fixed addresses, it is
    incongruous that we end up displaying hardware vs. software-managed MSI
    regions to userspace differently, especially since ARM-based systems may
    actually require one or the other, or even potentially both at once,
    (which iommu-dma currently has no hope of dealing with at all). Let's
    resolve the former user-visible inconsistency ASAP before the ABI has
    been baked into a kernel release, in a way that also lays the groundwork
    for the latter shortcoming to be addressed by follow-up patches.
    
    For clarity, rename the software-managed type to IOMMU_RESV_SW_MSI, use
    IOMMU_RESV_MSI to describe the hardware type, and document everything a
    little bit. Since the x86 MSI remapping hardware falls squarely under
    this meaning of IOMMU_RESV_MSI, apply that type to their regions as well,
    so that we tell the same story to userspace across all platforms.
    
    Secondly, as the various region types require quite different handling,
    and it really makes little sense to ever try combining them, convert the
    bitfield-esque #defines to a plain enum in the process before anyone
    gets the wrong impression.
    
    Fixes: d30ddcaa ("iommu: Add a new type field in iommu_resv_region")
    Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
    CC: Alex Williamson <alex.williamson@redhat.com>
    CC: David Woodhouse <dwmw2@infradead.org>
    CC: kvm@vger.kernel.org
    Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
    Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
    9d3a4de4
iommu.c 46.4 KB