Re: [PATCH v4 00/15] arm64: Support for running as a guest in Arm CCA

[Will Deacon]

Hi Steven,

On Mon, Jul 01, 2024 at 10:54:50AM +0100, Steven Price wrote:
> This series adds support for running Linux in a protected VM under the
> Arm Confidential Compute Architecture (CCA). This has been updated
> following the feedback from the v3 posting[1]. Thanks for the feedback!
> Individual patches have a change log. But things to highlight:

Hold onto your hat, I'm going to dust off our pKVM protected guest
changes and see what we can share here! I've left a few comments on the
series, but the main differences seem to be:

  - You try to probe really early
  - You have that horrible split IPA space thing from the RSI spec

but some of the mechanisms are broadly similar (e.g. implementing the
set_memory_*crypted() API).

Hopefully I can give your GIC changes a spin, too.

Just one minor (but probably annoying) comment:

>  arch/arm64/Kconfig                            |   3 +
>  arch/arm64/include/asm/fixmap.h               |   2 +-
>  arch/arm64/include/asm/io.h                   |   8 +-
>  arch/arm64/include/asm/mem_encrypt.h          |  17 ++
>  arch/arm64/include/asm/pgtable-hwdef.h        |   6 -
>  arch/arm64/include/asm/pgtable-prot.h         |   3 +
>  arch/arm64/include/asm/pgtable.h              |  13 +-
>  arch/arm64/include/asm/rsi.h                  |  64 ++++++
>  arch/arm64/include/asm/rsi_cmds.h             | 134 +++++++++++
>  arch/arm64/include/asm/rsi_smc.h              | 142 ++++++++++++
>  arch/arm64/include/asm/set_memory.h           |   3 +
>  arch/arm64/kernel/Makefile                    |   3 +-
>  arch/arm64/kernel/efi.c                       |   2 +-
>  arch/arm64/kernel/rsi.c                       | 104 +++++++++
>  arch/arm64/kernel/setup.c                     |   8 +
>  arch/arm64/mm/init.c                          |  10 +-
>  arch/arm64/mm/pageattr.c                      |  76 ++++++-
>  drivers/firmware/psci/psci.c                  |  25 +++
>  drivers/irqchip/irq-gic-v3-its.c              | 142 +++++++++---
>  drivers/virt/coco/Kconfig                     |   2 +
>  drivers/virt/coco/Makefile                    |   1 +
>  drivers/virt/coco/arm-cca-guest/Kconfig       |  11 +
>  drivers/virt/coco/arm-cca-guest/Makefile      |   2 +
>  .../virt/coco/arm-cca-guest/arm-cca-guest.c   | 211 ++++++++++++++++++
>  include/linux/psci.h                          |   5 +
>  25 files changed, 953 insertions(+), 44 deletions(-)
>  create mode 100644 arch/arm64/include/asm/mem_encrypt.h
>  create mode 100644 arch/arm64/include/asm/rsi.h
>  create mode 100644 arch/arm64/include/asm/rsi_cmds.h
>  create mode 100644 arch/arm64/include/asm/rsi_smc.h
>  create mode 100644 arch/arm64/kernel/rsi.c
>  create mode 100644 drivers/virt/coco/arm-cca-guest/Kconfig
>  create mode 100644 drivers/virt/coco/arm-cca-guest/Makefile
>  create mode 100644 drivers/virt/coco/arm-cca-guest/arm-cca-guest.c

Any chance of some documentation, please?

Cheers,

Will