linux-kernel - Re: [PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the RMM

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Message-ID: <fc168fe2-2b19-4930-85cf-047260aeaef0@redhat.com>
Date: Fri, 6 Sep 2024 10:11:37 +1000
From: Gavin Shan <gshan@...hat.com>
To: Steven Price <steven.price@....com>, kvm@...r.kernel.org,
 kvmarm@...ts.linux.dev
Cc: 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>,
 Suzuki K Poulose <suzuki.poulose@....com>, 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>
Subject: Re: [PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the
 RMM

Hi Steven,

On 8/22/24 1:38 AM, Steven Price wrote:
> The RMM (Realm Management Monitor) provides functionality that can be
> accessed by SMC calls from the host.
> 
> The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1
> 
> [1] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
> 
> Signed-off-by: Steven Price <steven.price@....com>
> ---
> Changes since v3:
>   * Update to match RMM spec v1.0-rel0-rc1.
> Changes since v2:
>   * Fix specification link.
>   * Rename rec_entry->rec_enter to match spec.
>   * Fix size of pmu_ovf_status to match spec.
> ---
>   arch/arm64/include/asm/rmi_smc.h | 253 +++++++++++++++++++++++++++++++
>   1 file changed, 253 insertions(+)
>   create mode 100644 arch/arm64/include/asm/rmi_smc.h
> 

[...]

> +
> +#define RMI_FEATURE_REGISTER_0_S2SZ		GENMASK(7, 0)
> +#define RMI_FEATURE_REGISTER_0_LPA2		BIT(8)
> +#define RMI_FEATURE_REGISTER_0_SVE_EN		BIT(9)
> +#define RMI_FEATURE_REGISTER_0_SVE_VL		GENMASK(13, 10)
> +#define RMI_FEATURE_REGISTER_0_NUM_BPS		GENMASK(19, 14)
> +#define RMI_FEATURE_REGISTER_0_NUM_WPS		GENMASK(25, 20)
> +#define RMI_FEATURE_REGISTER_0_PMU_EN		BIT(26)
> +#define RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS	GENMASK(31, 27)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_256	BIT(32)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_512	BIT(33)
> +#define RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS	GENMASK(37, 34)
> +#define RMI_FEATURE_REGISTER_0_MAX_RECS_ORDER	GENMASK(41, 38)
> +

Those definitions aren't consistent to tf-rmm at least. For example, the latest tf-rmm
has bit-28 and bit-29 for RMI_FEATURE_REGISTER_0_HASH_SHA_{256, 512}. I didn't check the
specification yet, but they need to be corrected in Linux host or tf-rmm.

   git@...hub.com:TF-RMM/tf-rmm.git
   head: 258b7952640b Merge "fix(tools/clang-tidy): ignore header include check" into integration

   [gshan@...an tf-rmm]$ git grep RMI_FEATURE_REGISTER_0_HASH_SHA.*_SHIFT
   lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_256_SHIFT     UL(28)
   lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_512_SHIFT     UL(29)

Due to the inconsistent definitions, I'm unable to start a guest with the following
combination: linux-host/cca-host/v4, linux-guest/cca-guest/v5, kvmtool/cca/v2.

   # ./start_guest.sh
   Info: # lkvm run -k Image -m 256 -c 2 --name guest-152
   [  145.894085] config_realm_hash_algo: unsupported ALGO_SHA256 by rmm_feat_reg0=0x0000000034488e30
   KVM_CAP_RME(KVM_CAP_ARM_RME_CONFIG_REALM) hash_algo: Invalid argument

Thanks,
Gavin