linux-kernel - Re: [PATCH v6 09/11] arm64: Enable memory encrypt for Realms

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Message-ID: <6fda5d7d-4214-460c-a727-9bb3382aa78f@redhat.com>
Date: Tue, 8 Oct 2024 12:56:36 +1000
From: Gavin Shan <gshan@...hat.com>
To: Steven Price <steven.price@....com>, kvm@...r.kernel.org,
 kvmarm@...ts.linux.dev
Cc: Suzuki K Poulose <suzuki.poulose@....com>,
 Catalin Marinas <catalin.marinas@....com>, Marc Zyngier <maz@...nel.org>,
 Will Deacon <will@...nel.org>, James Morse <james.morse@....com>,
 Oliver Upton <oliver.upton@...ux.dev>, Zenghui Yu <yuzenghui@...wei.com>,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 Joey Gouly <joey.gouly@....com>, Alexandru Elisei
 <alexandru.elisei@....com>, Christoffer Dall <christoffer.dall@....com>,
 Fuad Tabba <tabba@...gle.com>, linux-coco@...ts.linux.dev,
 Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>,
 Shanker Donthineni <sdonthineni@...dia.com>, Alper Gun
 <alpergun@...gle.com>, "Aneesh Kumar K . V" <aneesh.kumar@...nel.org>
Subject: Re: [PATCH v6 09/11] arm64: Enable memory encrypt for Realms

On 10/5/24 12:43 AM, Steven Price wrote:
> From: Suzuki K Poulose <suzuki.poulose@....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@....com>
> Co-developed-by: Steven Price <steven.price@....com>
> Signed-off-by: Steven Price <steven.price@....com>
> Reviewed-by: Catalin Marinas <catalin.marinas@....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@...hat.com>