[PATCH v6 09/11] arm64: Enable memory encrypt for Realms

[Gavin Shan]

On 10/5/24 12:43 AM, Steven Price wrote:
> From: Suzuki K Poulose <suzuki.poulose at arm.com>
> 
> Use the memory encryption APIs to trigger a RSI call to request a
> transition between protected memory and shared memory (or vice versa)
> and updating the kernel's linear map of modified pages to flip the top
> bit of the IPA. This requires that block mappings are not used in the
> direct map for realm guests.
> 
> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Co-developed-by: Steven Price <steven.price at arm.com>
> Signed-off-by: Steven Price <steven.price at arm.com>
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
> ---
> Changes since v5:
>   * Added comments and a WARN() in realm_set_memory_{en,de}crypted() to
>     explain that memory is leaked if the transition fails. This means the
>     callers no longer need to provide their own WARN.
> Changed since v4:
>   * Reworked to use the new dispatcher for the mem_encrypt API
> Changes since v3:
>   * Provide pgprot_{de,en}crypted() macros
>   * Rename __set_memory_encrypted() to __set_memory_enc_dec() since it
>     both encrypts and decrypts.
> Changes since v2:
>   * Fix location of set_memory_{en,de}crypted() and export them.
>   * Break-before-make when changing the top bit of the IPA for
>     transitioning to/from shared.
> ---
>   arch/arm64/Kconfig                   |  3 +
>   arch/arm64/include/asm/mem_encrypt.h |  9 +++
>   arch/arm64/include/asm/pgtable.h     |  5 ++
>   arch/arm64/include/asm/set_memory.h  |  3 +
>   arch/arm64/kernel/rsi.c              | 16 +++++
>   arch/arm64/mm/pageattr.c             | 90 +++++++++++++++++++++++++++-
>   6 files changed, 123 insertions(+), 3 deletions(-)
> 
Reviewed-by: Gavin Shan <gshan at redhat.com>