[PATCH 00/22] KVM: arm64: nv: Implement FEAT_HAFDBS, FEAT_HAFT

[Oliver Upton <oupton@kernel.org>]

KVM's support for hardware descriptor updates has been lacking, owing in
large part to the fact that the most widely available NV2 hardware
actually lacks HAFDBS :)

This series brings support for hardware dirty state and table Access
flags to the nested MMU. While KVM uses neither of these features, the
kernel definitely does in the stage-1 page tables. Since there is only
one hypervisor to rule them all, implementing this stuff at stage-2 is
mostly motivated by the desire to enable guest stage-1 :)

Implementing dirty state at stage-2 is a bit more challenging than
anticipated, I'm in the middle of seeking a relaxation from Arm that
would make this all architectural. See the last patch for the details.

Applies to kvmarm/fixes since this depends on some of the earlier VNCR
rework. Lightly tested on an implementation with HAFT.

Oliver Upton (22):
  KVM: arm64: nv: Introduce struct for stage-2 walk step
  KVM: arm64: nv: Consolidate computation of stage-2 permissions
  KVM: arm64: nv: Get rid of kvm_s2_trans*() accessors
  KVM: arm64: nv: Only shadow writable-dirty guest descs as writable
  KVM: arm64: nv: Pass an access descriptor for stage-2 walks
  KVM: arm64: nv: Use a helper for stage-2 descriptor updates
  KVM: arm64: nv: Set dirty state at stage-2
  KVM: arm64: nv: Treat DBM as writable at stage-2
  KVM: arm64: Compute S1 permissions as part of s1_walk()
  KVM: arm64: Plumb through access descriptor for stage-1
  KVM: arm64: Use a struct for stage-1 walk context
  KVM: arm64: Create helper for stage-1 descriptor updates
  KVM: arm64: Set dirty state at stage-1
  KVM: arm64: Grant write permission when DBM is set at S1
  KVM: arm64: Don't update descriptors for "non-arch" access
  KVM: arm64: nv: Expose FEAT_HAFDBS
  KVM: arm64: Set Access flag on table descriptors at stage-1
  KVM: arm64: nv: Set access flag on table descriptors at stage-2
  KVM: arm64: nv: Expose FEAT_HAFT
  KVM: arm64: selftests: Only test AF behavior for emulated AT insns
  KVM: arm64: selftests: Test that AT emulation for FEAT_HAFT
  HACK: KVM: arm64: nv: Set the dirty state for CMOs that fetch for
    write

 arch/arm64/include/asm/kvm_arm.h       |   1 +
 arch/arm64/include/asm/kvm_nested.h    |  94 +++------
 arch/arm64/include/asm/kvm_pgtable.h   |  17 +-
 arch/arm64/kvm/at.c                    | 267 +++++++++++++++++--------
 arch/arm64/kvm/hyp/pgtable.c           |  11 -
 arch/arm64/kvm/mmu.c                   |  36 +++-
 arch/arm64/kvm/nested.c                | 251 ++++++++++++++++-------
 tools/testing/selftests/kvm/arm64/at.c | 102 ++++++++--
 8 files changed, 515 insertions(+), 264 deletions(-)


base-commit: d098bb75d14fde2f12155f1a95ec0168160867ce
-- 
2.47.3