[PATCH v8 0/5] MTE support for KVM guest

[Steven Price]

Another round of updates following review comments from Marc (thanks!).
This is rather late for v5.12, so I'll rebase again after -rc1 is out.

This series adds support for using the Arm Memory Tagging Extensions
(MTE) in a KVM guest.

This version splits the change to the tag synchronisation out to it's
own patch (patch 1), and also separates the introduction and exposing of
KVM_ARM_CAP_MTE into two patches (2 and 4) to avoid a dependency problem
with the save/restore patch (3). As before patch 5 is an RFC for adding
a new ioctl for reading/writing tags (I would appreciate feedback!).

Changes since v7[1]:
 * Split into hopefully more logic patches.
 * Save/restore of TFSRE0_EL1 is now done in C code.
 * Make save/restore of TFSR_EL1 conditional on the VM having MTE
   enabled.
 * Replaced register descriptions boilerplate in sys_regs.c with a new
   MTE_REG() macro.

[1] https://lore.kernel.org/r/20210115152811.8398-1-steven.price%40arm.com

Steven Price (5):
  arm64: mte: Sync tags for pages where PTE is untagged
  arm64: kvm: Introduce MTE VM feature
  arm64: kvm: Save/restore MTE registers
  arm64: kvm: Expose KVM_ARM_CAP_MTE
  KVM: arm64: ioctl to fetch/store tags in a guest

 arch/arm64/include/asm/kvm_emulate.h       |  3 +
 arch/arm64/include/asm/kvm_host.h          |  9 +++
 arch/arm64/include/asm/kvm_mte.h           | 66 ++++++++++++++++++++++
 arch/arm64/include/asm/pgtable.h           |  2 +-
 arch/arm64/include/asm/sysreg.h            |  3 +-
 arch/arm64/include/uapi/asm/kvm.h          | 13 +++++
 arch/arm64/kernel/asm-offsets.c            |  3 +
 arch/arm64/kernel/mte.c                    | 16 ++++--
 arch/arm64/kvm/arm.c                       | 66 ++++++++++++++++++++++
 arch/arm64/kvm/hyp/entry.S                 |  7 +++
 arch/arm64/kvm/hyp/exception.c             |  3 +-
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 21 +++++++
 arch/arm64/kvm/mmu.c                       | 16 ++++++
 arch/arm64/kvm/sys_regs.c                  | 28 +++++++--
 include/uapi/linux/kvm.h                   |  2 +
 15 files changed, 246 insertions(+), 12 deletions(-)
 create mode 100644 arch/arm64/include/asm/kvm_mte.h

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2.20.1