Re: [PATCH v4 01/15] arm64: rsi: Add RSI definitions
From: Gavin Shan
Date: Tue Jul 23 2024 - 02:23:15 EST
On 7/1/24 7:54 PM, Steven Price wrote:
From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
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 A-eac5.
[1] https://developer.arm.com/documentation/den0137/latest
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
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 | 38 ++++++++
arch/arm64/include/asm/rsi_smc.h | 142 ++++++++++++++++++++++++++++++
2 files changed, 180 insertions(+)
create mode 100644 arch/arm64/include/asm/rsi_cmds.h
create mode 100644 arch/arm64/include/asm/rsi_smc.h
Some nits and questions like below.
diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
new file mode 100644
index 000000000000..89e907f3af0c
--- /dev/null
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -0,0 +1,38 @@
+/* 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>
+
+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;
+}
+
+#endif
#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..b3b3aff88f71
--- /dev/null
+++ b/arch/arm64/include/asm/rsi_smc.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_RSI_SMC_H_
+#define __ASM_RSI_SMC_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.
+ */
+
+#define SMC_RSI_CALL_BASE 0xC4000000
+
+/*
+ * The major version number of the RSI implementation. Increase this whenever
+ * the binary format or semantics of the SMC calls change.
+ */
+#define RSI_ABI_VERSION_MAJOR 1
+
+/*
+ * The minor version number of the RSI implementation. Increase this when
+ * a bug is fixed, or a feature is added without breaking binary compatibility.
+ */
+#define RSI_ABI_VERSION_MINOR 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 0
+#define RSI_ERROR_INPUT 1
+#define RSI_ERROR_STATE 2
+#define RSI_INCOMPLETE 3
+
I think these return values are copied from tf-rmm/lib/smc/include/smc-rsi.h, but
UL() prefix has been missed. It's still probably worthy to have it to indicate the
width of the return values. Besides, it seems that RSI_ERROR_COUNT is also missed
here.
+#define SMC_RSI_FID(_x) (SMC_RSI_CALL_BASE + (_x))
+
+#define SMC_RSI_ABI_VERSION SMC_RSI_FID(0x190)
+
+/*
+ * arg1 == Challenge value, bytes: 0 - 7
+ * arg2 == Challenge value, bytes: 7 - 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)
+
In tf-rmm/lib/smc/include/smc-rsi.h, it is SMC_RSI_ATTEST_TOKEN_INIT instead
of SMC_RSI_ATTESTATION_TOKEN_INIT. The short description for all SMC calls have
been dropped and I think they're worthy to be kept. At least, it helps readers
to understand what the SMC call does. For this particular SMC call, the short
description is something like below:
/*
* Initialize 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)
+
SMC_RSI_ATTEST_TOKEN_CONTINUE as defined in tf-rmm.
+/*
+ * 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
+ * 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)
+
+/*
+ * arg1 == Index, which measurements slot to read
+ * ret0 == Status / error
+ * ret1 == Measurement value, bytes: 0 - 7
+ * ret2 == Measurement value, bytes: 7 - 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)
+
The order of these SMC call definitions are sorted based on their corresponding
function IDs. For example, SMC_RSI_MEASUREMENT_READ would be appearing prior to
SMC_RSI_MEASUREMENT_EXTEND.
+#ifndef __ASSEMBLY__
+
+struct realm_config {
+ union {
+ struct {
+ unsigned long ipa_bits; /* Width of IPA in bits */
+ unsigned long hash_algo; /* Hash algorithm */
+ };
+ u8 pad[0x1000];
+ };
+} __aligned(0x1000);
+
This describes the argument to SMC call RSI_REALM_CONFIG and its address needs to
be aligned to 0x1000. Otherwise, RSI_ERROR_INPUT is returned. This maybe worthy
a comment to explain it why we need 0x1000 alignment here.
It seems the only 4KB page size (GRANULE_SIZE) is supported by tf-rmm at present.
The fixed alignment (0x1000) becomes broken if tf-rmm is extended to support
64KB in future. Maybe tf-rmm was designed to work with the minimal page size (4KB).
+#endif /* __ASSEMBLY__ */
+
+/*
+ * arg1 == struct realm_config addr
+ * ret0 == Status / error
+ */
+#define SMC_RSI_REALM_CONFIG SMC_RSI_FID(0x196)
+
+/*
+ * 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 0
+#define RSI_CHANGE_DESTROYED 1
+
+/*
+ * arg1 == IPA of target page
+ * ret0 == Status / error
+ * ret1 == RIPAS value
+ */
+#define SMC_RSI_IPA_STATE_GET SMC_RSI_FID(0x198)
+
+/*
+ * 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