Re: [PATCH v5 03/19] arm64: rsi: Add RSI definitions

[Gavin Shan <gshan@redhat.com>]

On 8/19/24 11:19 PM, Steven Price wrote:
> From: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> The RMM (Realm Management Monitor) provides functionality that can be
> accessed by a realm guest through SMC (Realm Services Interface) calls.
> 
> 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: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v4:
>   * Update to match the latest RMM spec version 1.0-rel0-rc1.
>   * Make use of the ARM_SMCCC_CALL_VAL macro.
>   * Cast using (_UL macro) various values to unsigned long.
> Changes since v3:
>   * Drop invoke_rsi_fn_smc_with_res() function and call arm_smccc_smc()
>     directly instead.
>   * Rename header guard in rsi_smc.h to be consistent.
> Changes since v2:
>   * Rename rsi_get_version() to rsi_request_version()
>   * Fix size/alignment of struct realm_config
> ---
>   arch/arm64/include/asm/rsi_cmds.h | 136 +++++++++++++++++++++
>   arch/arm64/include/asm/rsi_smc.h  | 189 ++++++++++++++++++++++++++++++
>   2 files changed, 325 insertions(+)
>   create mode 100644 arch/arm64/include/asm/rsi_cmds.h
>   create mode 100644 arch/arm64/include/asm/rsi_smc.h
> 

With the following minor comments addressed:

Reviewed-by: Gavin Shan <gshan@redht.com>

> diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
> new file mode 100644
> index 000000000000..968b03f4e703
> --- /dev/null
> +++ b/arch/arm64/include/asm/rsi_cmds.h
> @@ -0,0 +1,136 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#ifndef __ASM_RSI_CMDS_H
> +#define __ASM_RSI_CMDS_H
> +
> +#include <linux/arm-smccc.h>
> +
> +#include <asm/rsi_smc.h>
> +
> +#define RSI_GRANULE_SHIFT		12
> +#define RSI_GRANULE_SIZE		(_AC(1, UL) << RSI_GRANULE_SHIFT)
> +
> +enum ripas {
> +	RSI_RIPAS_EMPTY = 0,
> +	RSI_RIPAS_RAM = 1,
> +	RSI_RIPAS_DESTROYED = 2,
> +	RSI_RIPAS_IO = 3,
> +};
> +

The 'RSI_RIPAS_IO' corresponds to 'RIPAS_DEV' defined in tf-rmm/lib/s2tt/include/ripas.h.
Shall we rename it to RSI_RIPAS_DEV so that the name is matched with that defined in
tf-rmm?

---> tf-rmm/lib/s2tt/include/ripas.h

/*
  * The RmmRipas enumeration represents realm IPA state.
  *
  * Map RmmRipas to RmiRipas to simplify code/decode operations.
  */
enum ripas {
         RIPAS_EMPTY = RMI_EMPTY,        /* Unused IPA for Realm */
         RIPAS_RAM = RMI_RAM,            /* IPA used for Code/Data by Realm */
         RIPAS_DESTROYED = RMI_DESTROYED,/* IPA is inaccessible to the Realm */
         RIPAS_DEV                       /* Address where memory of an assigned
                                            Realm device is mapped */
};

> +static inline unsigned long rsi_request_version(unsigned long req,
> +						unsigned long *out_lower,
> +						unsigned long *out_higher)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(SMC_RSI_ABI_VERSION, req, 0, 0, 0, 0, 0, 0, &res);
> +
> +	if (out_lower)
> +		*out_lower = res.a1;
> +	if (out_higher)
> +		*out_higher = res.a2;
> +
> +	return res.a0;
> +}
> +
> +static inline unsigned long rsi_get_realm_config(struct realm_config *cfg)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(SMC_RSI_REALM_CONFIG, virt_to_phys(cfg),
> +		      0, 0, 0, 0, 0, 0, &res);
> +	return res.a0;
> +}
> +
> +static inline unsigned long rsi_set_addr_range_state(phys_addr_t start,
> +						     phys_addr_t end,
> +						     enum ripas state,
> +						     unsigned long flags,
> +						     phys_addr_t *top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_smc(SMC_RSI_IPA_STATE_SET, start, end, state,
> +		      flags, 0, 0, 0, &res);
> +
> +	if (top)
> +		*top = res.a1;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rsi_attestation_token_init - Initialise the operation to retrieve an
> + * attestation token.
> + *
> + * @challenge:	The challenge data to be used in the attestation token
> + *		generation.
> + * @size:	Size of the challenge data in bytes.
> + *
> + * Initialises the attestation token generation and returns an upper bound
> + * on the attestation token size that can be used to allocate an adequate
> + * buffer. The caller is expected to subsequently call
> + * rsi_attestation_token_continue() to retrieve the attestation token data on
> + * the same CPU.
> + *
> + * Returns:
> + *  On success, returns the upper limit of the attestation report size.
> + *  Otherwise, -EINVAL
> + */
> +static inline unsigned long
> +rsi_attestation_token_init(const u8 *challenge, unsigned long size)
> +{
> +	struct arm_smccc_1_2_regs regs = { 0 };
> +
> +	/* The challenge must be at least 32bytes and at most 64bytes */
> +	if (!challenge || size < 32 || size > 64)
> +		return -EINVAL;
> +
> +	regs.a0 = SMC_RSI_ATTESTATION_TOKEN_INIT;
> +	memcpy(&regs.a1, challenge, size);
> +	arm_smccc_1_2_smc(&regs, &regs);
> +
> +	if (regs.a0 == RSI_SUCCESS)
> +		return regs.a1;
> +
> +	return -EINVAL;
> +}
> +

The type of the return value would be 'long' instead of 'unsigned long' since
'-EINVAL' can be returned.

> +/**
> + * rsi_attestation_token_continue - Continue the operation to retrieve an
> + * attestation token.
> + *
> + * @granule: {I}PA of the Granule to which the token will be written.
> + * @offset:  Offset within Granule to start of buffer in bytes.
> + * @size:    The size of the buffer.
> + * @len:     The number of bytes written to the buffer.
> + *
> + * Retrieves up to a RSI_GRANULE_SIZE worth of token data per call. The caller
> + * is expected to call rsi_attestation_token_init() before calling this
> + * function to retrieve the attestation token.
> + *
> + * Return:
> + * * %RSI_SUCCESS     - Attestation token retrieved successfully.
> + * * %RSI_INCOMPLETE  - Token generation is not complete.
> + * * %RSI_ERROR_INPUT - A parameter was not valid.
> + * * %RSI_ERROR_STATE - Attestation not in progress.
> + */
> +static inline int rsi_attestation_token_continue(phys_addr_t granule,
> +						 unsigned long offset,
> +						 unsigned long size,
> +						 unsigned long *len)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RSI_ATTESTATION_TOKEN_CONTINUE,
> +			     granule, offset, size, 0, &res);
> +
> +	if (len)
> +		*len = res.a1;
> +	return res.a0;
> +}
> +
> +#endif /* __ASM_RSI_CMDS_H */
> diff --git a/arch/arm64/include/asm/rsi_smc.h b/arch/arm64/include/asm/rsi_smc.h
> new file mode 100644
> index 000000000000..b76b03a8fea8
> --- /dev/null
> +++ b/arch/arm64/include/asm/rsi_smc.h
> @@ -0,0 +1,189 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#ifndef __ASM_RSI_SMC_H_
> +#define __ASM_RSI_SMC_H_
> +
> +#include <linux/arm-smccc.h>
> +
> +/*
> + * This file describes the Realm Services Interface (RSI) Application Binary
> + * Interface (ABI) for SMC calls made from within the Realm to the RMM and
> + * serviced by the RMM.
> + */
> +
> +/*
> + * The major version number of the RSI implementation.  This is increased when
> + * the binary format or semantics of the SMC calls change.
> + */
> +#define RSI_ABI_VERSION_MAJOR		UL(1)
> +
> +/*
> + * The minor version number of the RSI implementation.  This is increased when
> + * a bug is fixed, or a feature is added without breaking binary compatibility.
> + */
> +#define RSI_ABI_VERSION_MINOR		UL(0)
> +
> +#define RSI_ABI_VERSION			((RSI_ABI_VERSION_MAJOR << 16) | \
> +					 RSI_ABI_VERSION_MINOR)
> +
> +#define RSI_ABI_VERSION_GET_MAJOR(_version) ((_version) >> 16)
> +#define RSI_ABI_VERSION_GET_MINOR(_version) ((_version) & 0xFFFF)
> +
> +#define RSI_SUCCESS		UL(0)
> +#define RSI_ERROR_INPUT		UL(1)
> +#define RSI_ERROR_STATE		UL(2)
> +#define RSI_INCOMPLETE		UL(3)
> +#define RSI_ERROR_UNKNOWN	UL(4)
> +
> +#define SMC_RSI_FID(n)		ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,      \
> +						   ARM_SMCCC_SMC_64,         \
> +						   ARM_SMCCC_OWNER_STANDARD, \
> +						   n)
> +
> +/*
> + * Returns RSI version.
> + *
> + * arg1 == Requested interface revision
> + * ret0 == Status /error
> + * ret1 == Lower implemented interface revision
> + * ret2 == Higher implemented interface revision
> + */
> +#define SMC_RSI_ABI_VERSION	SMC_RSI_FID(0x190)
> +
> +/*
> + * Read feature register.
> + *
> + * arg1 == Feature register index
> + * ret0 == Status /error
               ^^^^^^^^^^^^^
               Status / error

> + * ret1 == Feature register value
> + */
> +#define SMC_RSI_FEATURES			SMC_RSI_FID(0x191)
> +
> +/*
> + * Read measurement for the current Realm.
> + *
> + * arg1 == Index, which measurements slot to read
> + * ret0 == Status / error
> + * ret1 == Measurement value, bytes:  0 -  7
> + * ret2 == Measurement value, bytes:  7 - 15
                                          ^^^^^^
                                          8 - 15

> + * ret3 == Measurement value, bytes: 16 - 23
> + * ret4 == Measurement value, bytes: 24 - 31
> + * ret5 == Measurement value, bytes: 32 - 39
> + * ret6 == Measurement value, bytes: 40 - 47
> + * ret7 == Measurement value, bytes: 48 - 55
> + * ret8 == Measurement value, bytes: 56 - 63
> + */
> +#define SMC_RSI_MEASUREMENT_READ		SMC_RSI_FID(0x192)
> +
> +/*
> + * Extend Realm Extensible Measurement (REM) value.
> + *
> + * arg1  == Index, which measurements slot to extend
> + * arg2  == Size of realm measurement in bytes, max 64 bytes
> + * arg3  == Measurement value, bytes:  0 -  7
> + * arg4  == Measurement value, bytes:  7 - 15
                                           ^^^^^^
                                           8 - 15

> + * arg5  == Measurement value, bytes: 16 - 23
> + * arg6  == Measurement value, bytes: 24 - 31
> + * arg7  == Measurement value, bytes: 32 - 39
> + * arg8  == Measurement value, bytes: 40 - 47
> + * arg9  == Measurement value, bytes: 48 - 55
> + * arg10 == Measurement value, bytes: 56 - 63
> + * ret0  == Status / error
> + */
> +#define SMC_RSI_MEASUREMENT_EXTEND		SMC_RSI_FID(0x193)
> +
> +/*
> + * Initialize the operation to retrieve an attestation token.
> + *
> + * arg1 == Challenge value, bytes:  0 -  7
> + * arg2 == Challenge value, bytes:  7 - 15
                                        ^^^^^^
                                        8 - 15

> + * arg3 == Challenge value, bytes: 16 - 23
> + * arg4 == Challenge value, bytes: 24 - 31
> + * arg5 == Challenge value, bytes: 32 - 39
> + * arg6 == Challenge value, bytes: 40 - 47
> + * arg7 == Challenge value, bytes: 48 - 55
> + * arg8 == Challenge value, bytes: 56 - 63
> + * ret0 == Status / error
> + * ret1 == Upper bound of token size in bytes
> + */
> +#define SMC_RSI_ATTESTATION_TOKEN_INIT		SMC_RSI_FID(0x194)
> +
> +/*
> + * Continue the operation to retrieve an attestation token.
> + *
> + * arg1 == The IPA of token buffer
> + * arg2 == Offset within the granule of the token buffer
> + * arg3 == Size of the granule buffer
> + * ret0 == Status / error
> + * ret1 == Length of token bytes copied to the granule buffer
> + */
> +#define SMC_RSI_ATTESTATION_TOKEN_CONTINUE	SMC_RSI_FID(0x195)
> +
> +#ifndef __ASSEMBLY__
> +
> +struct realm_config {
> +	union {
> +		struct {
> +			unsigned long ipa_bits; /* Width of IPA in bits */
> +			unsigned long hash_algo; /* Hash algorithm */
> +		};
> +		u8 pad[0x200];
> +	};
> +	union {
> +		u8 rpv[64]; /* Realm Personalization Value */
> +		u8 pad2[0xe00];
> +	};
> +	/*
> +	 * The RMM requires the configuration structure to be aligned to a 4k
> +	 * boundary, ensure this happens by aligning this structure.
> +	 */
> +} __aligned(0x1000);
> +
> +#endif /* __ASSEMBLY__ */
> +
> +/*
> + * Read configuration for the current Realm.
> + *
> + * arg1 == struct realm_config addr
> + * ret0 == Status / error
> + */
> +#define SMC_RSI_REALM_CONFIG			SMC_RSI_FID(0x196)
> +
> +/*
> + * Request RIPAS of a target IPA range to be changed to a specified value.
> + *
> + * arg1 == Base IPA address of target region
> + * arg2 == Top of the region
> + * arg3 == RIPAS value
> + * arg4 == flags
> + * ret0 == Status / error
> + * ret1 == Top of modified IPA range
> + */
> +#define SMC_RSI_IPA_STATE_SET			SMC_RSI_FID(0x197)
> +
> +#define RSI_NO_CHANGE_DESTROYED			UL(0)
> +#define RSI_CHANGE_DESTROYED			UL(1)
> +

According to the linked specification, the description for the third return value
has been missed here.

ret2 == Whether the host accepted or rejected the request

> +/*
> + * Get RIPAS of a target IPA range.
> + *
> + * arg1 == Base IPA of target region
> + * arg2 == End of target IPA region
> + * ret0 == Status / error
> + * ret1 == Top of IPA region which has the reported RIPAS value
> + * ret2 == RIPAS value
> + */
> +#define SMC_RSI_IPA_STATE_GET			SMC_RSI_FID(0x198)
> +
> +/*
> + * Make a Host call.
> + *
> + * arg1 == IPA of host call structure
> + * ret0 == Status / error
> + */
> +#define SMC_RSI_HOST_CALL			SMC_RSI_FID(0x199)
> +
> +#endif /* __ASM_RSI_SMC_H_ */

Thanks,
Gavin