[RFC PATCH v3 04/11] coco: guest: arm64: Support guest-initiated TDI lock/unlock transitions

Aneesh Kumar K.V (Arm)
2026-03-12T08:05:15Z

Add guest helpers to drive TDI state transitions through RHI:
- cca_device_lock() -> RHI_DA_TDI_CONFIG_LOCKED
- cca_device_unlock() -> RHI_DA_TDI_CONFIG_UNLOCKED

Use these helpers in the PCI TSM lock/unlock callbacks so a successful
lock path returns a live pci_tsm handle and unlock transitions the device
back to unlocked state.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alexey Kardashevskiy <aik@amd.com>
Cc: Samuel Ortiz <sameo@rivosinc.com>
Cc: Xu Yilun <yilun.xu@linux.intel.com>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
drivers/virt/coco/arm-cca-guest/Makefile | 2 +-
drivers/virt/coco/arm-cca-guest/arm-cca.c | 9 ++++--
drivers/virt/coco/arm-cca-guest/rsi-da.c | 34 +++++++++++++++++++++++
drivers/virt/coco/arm-cca-guest/rsi-da.h | 2 ++
4 files changed, 44 insertions(+), 3 deletions(-)
create mode 100644 drivers/virt/coco/arm-cca-guest/rsi-da.c

diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
index 65c4cc52c154..11db7af095c9 100644
--- a/drivers/virt/coco/arm-cca-guest/Makefile
+++ b/drivers/virt/coco/arm-cca-guest/Makefile
@@ -2,4 +2,4 @@
obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o

arm-cca-guest-y += arm-cca.o
-arm-cca-guest-$(CONFIG_PCI_TSM) += rhi-da.o
+arm-cca-guest-$(CONFIG_PCI_TSM) += rhi-da.o rsi-da.o
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
index 07f74f67d22c..5e3a66315c70 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
@@ -211,14 +211,19 @@ static struct pci_tsm *cca_tsm_lock(struct tsm_dev *tsm_dev, struct pci_dev *pde
if (ret)
return ERR_PTR(ret);

- /* For now always return an error */
- return ERR_PTR(-EIO);
+ ret = cca_device_lock(pdev);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return &no_free_ptr(cca_dsc)->pci.base_tsm;
}

static void cca_tsm_unlock(struct pci_tsm *tsm)
{
struct cca_guest_dsc *cca_dsc = to_cca_guest_dsc(tsm->pdev);

+ cca_device_unlock(tsm->pdev);
+
kfree(cca_dsc);
}

diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
new file mode 100644
index 000000000000..2c3017933fb0
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 ARM Ltd.
+ */
+
+#include <linux/pci.h>
+#include <asm/rsi_cmds.h>
+
+#include "rsi-da.h"
+#include "rhi-da.h"
+
+int cca_device_lock(struct pci_dev *pdev)
+{
+ int ret;
+
+ ret = rhi_vdev_set_tdi_state(pdev, RHI_DA_TDI_CONFIG_LOCKED);
+ if (ret) {
+ pci_err(pdev, "failed to lock the device (%d)\n", ret);
+ return ret;
+ }
+ return 0;
+}
+
+int cca_device_unlock(struct pci_dev *pdev)
+{
+ int ret;
+
+ ret = rhi_vdev_set_tdi_state(pdev, RHI_DA_TDI_CONFIG_UNLOCKED);
+ if (ret) {
+ pci_err(pdev, "failed to unlock the device (%d)\n", ret);
+ return ret;
+ }
+ return 0;
+}
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
index 858bfdaf59c9..3619a75e160e 100644
--- a/drivers/virt/coco/arm-cca-guest/rsi-da.h
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
@@ -32,4 +32,6 @@ static inline int rsi_vdev_id(struct pci_dev *pdev)
PCI_DEVID(pdev->bus->number, pdev->devfn);
}

+int cca_device_lock(struct pci_dev *pdev);
+int cca_device_unlock(struct pci_dev *pdev);
#endif
--
2.43.0