[PATCH v2 01/11] coco: guest: arm64: Guest TSM callback and realm device lock support
From: Aneesh Kumar K.V (Arm)
Date: Mon Nov 17 2025 - 09:07:54 EST
Register the TSM callback when the DA feature is supported by RSI. The
build order is also adjusted so that the TSM class is created before the
arm-cca-guest driver is initialized.
In addition, add support for the TDISP lock sequence. Writing a TSM
(TEE Security Manager) device name from `/sys/class/tsm` into `tsm/lock`
triggers the realm device lock operation.
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
---
arch/arm64/include/asm/rsi.h | 3 ++
arch/arm64/include/asm/rsi_cmds.h | 17 +++++++
arch/arm64/include/asm/rsi_smc.h | 1 +
arch/arm64/kernel/rsi.c | 11 +++++
drivers/virt/coco/Makefile | 2 +-
drivers/virt/coco/arm-cca-guest/Kconfig | 8 ++-
drivers/virt/coco/arm-cca-guest/Makefile | 1 +
drivers/virt/coco/arm-cca-guest/arm-cca.c | 60 ++++++++++++++++++++++-
drivers/virt/coco/arm-cca-guest/rsi-da.h | 32 ++++++++++++
9 files changed, 132 insertions(+), 3 deletions(-)
create mode 100644 drivers/virt/coco/arm-cca-guest/rsi-da.h
diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h
index 2d2d363aaaee..12ccd1ed3dfa 100644
--- a/arch/arm64/include/asm/rsi.h
+++ b/arch/arm64/include/asm/rsi.h
@@ -67,4 +67,7 @@ static inline int rsi_set_memory_range_shared(phys_addr_t start,
return rsi_set_memory_range(start, end, RSI_RIPAS_EMPTY,
RSI_CHANGE_DESTROYED);
}
+
+bool rsi_has_da_feature(void);
+
#endif /* __ASM_RSI_H_ */
diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index 2c8763876dfb..6c2db7a24ef3 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -159,4 +159,21 @@ static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule,
return res.a0;
}
+/**
+ * rsi_features() - Read feature register
+ * @index: Feature register index
+ * @out: Feature register value is written to this pointer
+ *
+ * Return: RSI return code
+ */
+static inline unsigned long rsi_features(unsigned long index, unsigned long *out)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_1_1_invoke(SMC_RSI_FEATURES, index, &res);
+
+ *out = 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
index 6cb070eca9e9..8e486cdef9eb 100644
--- a/arch/arm64/include/asm/rsi_smc.h
+++ b/arch/arm64/include/asm/rsi_smc.h
@@ -53,6 +53,7 @@
*/
#define SMC_RSI_ABI_VERSION SMC_RSI_FID(0x190)
+#define RSI_FEATURE_REGISTER_0_DA BIT(0)
/*
* Read feature register.
*
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index 1b716d18b80e..2ec0f5dff02e 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -15,6 +15,7 @@
#include <asm/rsi.h>
static struct realm_config config;
+static unsigned long rsi_feat_reg0;
unsigned long prot_ns_shared;
EXPORT_SYMBOL(prot_ns_shared);
@@ -22,6 +23,12 @@ EXPORT_SYMBOL(prot_ns_shared);
DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
EXPORT_SYMBOL(rsi_present);
+bool rsi_has_da_feature(void)
+{
+ return u64_get_bits(rsi_feat_reg0, RSI_FEATURE_REGISTER_0_DA);
+}
+EXPORT_SYMBOL_GPL(rsi_has_da_feature);
+
bool cc_platform_has(enum cc_attr attr)
{
switch (attr) {
@@ -146,6 +153,10 @@ void __init arm64_rsi_init(void)
return;
if (WARN_ON(rsi_get_realm_config(&config)))
return;
+
+ if (WARN_ON(rsi_features(0, &rsi_feat_reg0)))
+ return;
+
prot_ns_shared = BIT(config.ipa_bits - 1);
if (arm64_ioremap_prot_hook_register(realm_ioremap_hook))
diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile
index cb52021912b3..57556d7c1cec 100644
--- a/drivers/virt/coco/Makefile
+++ b/drivers/virt/coco/Makefile
@@ -6,6 +6,6 @@ obj-$(CONFIG_EFI_SECRET) += efi_secret/
obj-$(CONFIG_ARM_PKVM_GUEST) += pkvm-guest/
obj-$(CONFIG_SEV_GUEST) += sev-guest/
obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/
-obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest/
obj-$(CONFIG_TSM) += tsm-core.o
obj-$(CONFIG_TSM_GUEST) += guest/
+obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest/
diff --git a/drivers/virt/coco/arm-cca-guest/Kconfig b/drivers/virt/coco/arm-cca-guest/Kconfig
index a42359a90558..66b2d9202b66 100644
--- a/drivers/virt/coco/arm-cca-guest/Kconfig
+++ b/drivers/virt/coco/arm-cca-guest/Kconfig
@@ -1,11 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
config ARM_CCA_GUEST
tristate "Arm CCA Guest driver"
depends on ARM64
+ depends on PCI_TSM
select TSM_REPORTS
select AUXILIARY_BUS
+ select TSM
help
- The driver provides userspace interface to request and
+ The driver provides userspace interface to request an
attestation report from the Realm Management Monitor(RMM).
+ If the DA feature is supported, it also register with TSM framework.
If you choose 'M' here, this module will be called
arm-cca-guest.
diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
index 75a120e24fda..bc3b2be4019f 100644
--- a/drivers/virt/coco/arm-cca-guest/Makefile
+++ b/drivers/virt/coco/arm-cca-guest/Makefile
@@ -1,4 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
+#
obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
arm-cca-guest-y += arm-cca.o
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
index dc96171791db..288fa53ad0af 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright (C) 2023 ARM Ltd.
+ * Copyright (C) 2025 ARM Ltd.
*/
#include <linux/auxiliary_bus.h>
@@ -15,6 +15,8 @@
#include <asm/rsi.h>
+#include "rsi-da.h"
+
/**
* struct arm_cca_token_info - a descriptor for the token buffer.
* @challenge: Pointer to the challenge data
@@ -192,6 +194,57 @@ static void unregister_cca_tsm_report(void *data)
tsm_report_unregister(&arm_cca_tsm_report_ops);
}
+static struct pci_tsm *cca_tsm_lock(struct tsm_dev *tsm_dev, struct pci_dev *pdev)
+{
+ int ret;
+
+ struct cca_guest_dsc *cca_dsc __free(kfree) =
+ kzalloc(sizeof(*cca_dsc), GFP_KERNEL);
+ if (!cca_dsc)
+ return ERR_PTR(-ENOMEM);
+
+ ret = pci_tsm_devsec_constructor(pdev, &cca_dsc->pci, tsm_dev);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return ERR_PTR(-EIO);
+}
+
+static void cca_tsm_unlock(struct pci_tsm *tsm)
+{
+ struct cca_guest_dsc *cca_dsc = to_cca_guest_dsc(tsm->pdev);
+
+ kfree(cca_dsc);
+}
+
+static struct pci_tsm_ops cca_devsec_pci_ops = {
+ .lock = cca_tsm_lock,
+ .unlock = cca_tsm_unlock,
+};
+
+static void cca_devsec_tsm_remove(void *tsm_dev)
+{
+ tsm_unregister(tsm_dev);
+}
+
+static int cca_devsec_tsm_register(struct auxiliary_device *adev)
+{
+ struct tsm_dev *tsm_dev;
+ int rc;
+
+ tsm_dev = tsm_register(&adev->dev, &cca_devsec_pci_ops);
+ if (IS_ERR(tsm_dev))
+ return PTR_ERR(tsm_dev);
+
+ rc = devm_add_action_or_reset(&adev->dev, cca_devsec_tsm_remove, tsm_dev);
+ if (rc) {
+ cca_devsec_tsm_remove(tsm_dev);
+ return rc;
+ }
+
+ return 0;
+}
+
static int cca_devsec_tsm_probe(struct auxiliary_device *adev,
const struct auxiliary_device_id *id)
{
@@ -212,6 +265,10 @@ static int cca_devsec_tsm_probe(struct auxiliary_device *adev,
return ret;
}
+ /* Allow tsm report even if tsm_register fails */
+ if (rsi_has_da_feature())
+ cca_devsec_tsm_register(adev);
+
return 0;
}
@@ -227,5 +284,6 @@ static struct auxiliary_driver cca_devsec_tsm_driver = {
};
module_auxiliary_driver(cca_devsec_tsm_driver);
MODULE_AUTHOR("Sami Mujawar <sami.mujawar@xxxxxxx>");
+MODULE_AUTHOR("Aneesh Kumar <aneesh.kumar@xxxxxxxxxx>");
MODULE_DESCRIPTION("Arm CCA Guest TSM Driver");
MODULE_LICENSE("GPL");
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
new file mode 100644
index 000000000000..5ad3b740710e
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2025 ARM Ltd.
+ */
+
+#ifndef _VIRT_COCO_RSI_DA_H_
+#define _VIRT_COCO_RSI_DA_H_
+
+#include <linux/pci.h>
+#include <linux/pci-tsm.h>
+#include <asm/rsi_smc.h>
+
+struct cca_guest_dsc {
+ struct pci_tsm_devsec pci;
+};
+
+static inline struct cca_guest_dsc *to_cca_guest_dsc(struct pci_dev *pdev)
+{
+ struct pci_tsm *tsm = pdev->tsm;
+
+ if (!tsm)
+ return NULL;
+ return container_of(tsm, struct cca_guest_dsc, pci.base_tsm);
+}
+
+static inline int rsi_vdev_id(struct pci_dev *pdev)
+{
+ return (pci_domain_nr(pdev->bus) << 16) |
+ PCI_DEVID(pdev->bus->number, pdev->devfn);
+}
+
+#endif
--
2.43.0