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Merge branch 'kvm-arm64/cacheable-pfnmap' into kvmarm/next

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* kvm-arm64/cacheable-pfnmap:
  : Cacheable PFNMAP support at stage-2, courtesy of Ankit Agrawal
  :
  : For historical reasons, KVM only allows cacheable mappings at stage-2
  : when a kernel alias exists in the direct map for the memory region. On
  : hardware without FEAT_S2FWB, this is necessary as KVM must do cache
  : maintenance to keep guest/host accesses coherent.
  :
  : This is unnecessarily restrictive on systems with FEAT_S2FWB and
  : CTR_EL0.DIC, as KVM no longer needs to perform cache maintenance to
  : maintain correctness.
  :
  : Allow cacheable mappings at stage-2 on supporting hardware when the
  : corresponding VMA has cacheable memory attributes and advertise a
  : capability to userspace such that a VMM can determine if a stage-2
  : mapping can be established (e.g. VFIO device).
  KVM: arm64: Expose new KVM cap for cacheable PFNMAP
  KVM: arm64: Allow cacheable stage 2 mapping using VMA flags
  KVM: arm64: Block cacheable PFNMAP mapping
  KVM: arm64: Assume non-PFNMAP/MIXEDMAP VMAs can be mapped cacheable
  KVM: arm64: Rename the device variable to s2_force_noncacheable

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2025-07-26 08:47:02 -07:00
commit c535d132a3
5 changed files with 103 additions and 24 deletions
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