[RFC PATCH v1 32/38] coco: guest: arm64: Add support for guest initiated TDI bind/unbind

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

Add RHI for VDEV_SET_TDI_STATE

Note: This is not part of RHI spec. This is a POC implementation
and will be later switced to correct interface defined by RHI.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/rhi.h              |  7 +++++
 arch/arm64/kernel/Makefile                |  2 +-
 arch/arm64/kernel/rhi.c                   | 35 +++++++++++++++++++++++
 drivers/virt/coco/arm-cca-guest/arm-cca.c | 22 ++++++++++++--
 drivers/virt/coco/arm-cca-host/arm-cca.c  |  8 ++++--
 5 files changed, 69 insertions(+), 5 deletions(-)
 create mode 100644 arch/arm64/kernel/rhi.c

diff --git a/arch/arm64/include/asm/rhi.h b/arch/arm64/include/asm/rhi.h
index d3c22e582678..993b4b15b057 100644
--- a/arch/arm64/include/asm/rhi.h
+++ b/arch/arm64/include/asm/rhi.h
@@ -16,6 +16,7 @@
 #define RHI_DA_FEATURES			SMC_RHI_CALL(0x004d)
 #define RHI_DA_OBJECT_SIZE		SMC_RHI_CALL(0x004e)
 #define RHI_DA_OBJECT_READ		SMC_RHI_CALL(0x004f)
+#define RHI_DA_VDEV_SET_TDI_STATE	SMC_RHI_CALL(0x0052)
 
 #define RHI_DA_OBJECT_CERTIFICATE		0x1
 #define RHI_DA_OBJECT_MEASUREMENT		0x2
@@ -29,4 +30,10 @@
 #define RHI_ERROR_DATA_NOT_AVAILABLE		0x4
 #define RHI_ERROR_INVALID_OFFSET		0x5
 #define RHI_ERROR_INVALID_ADDR			0x6
+
+#define RHI_DA_TDI_CONFIG_UNLOCKED		0x0
+#define RHI_DA_TDI_CONFIG_LOCKED		0x1
+#define RHI_DA_TDI_CONFIG_RUN			0x2
+long rhi_da_vdev_set_tdi_state(unsigned long vdev_id, unsigned long target_state);
+
 #endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index a2faf0049dab..dde8fa78852c 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -34,7 +34,7 @@ obj-y			:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   cpufeature.o alternative.o cacheinfo.o		\
 			   smp.o smp_spin_table.o topology.o smccc-call.o	\
 			   syscall.o proton-pack.o idle.o patching.o pi/	\
-			   rsi.o jump_label.o
+			   rsi.o jump_label.o rhi.o
 
 obj-$(CONFIG_COMPAT)			+= sys32.o signal32.o			\
 					   sys_compat.o
diff --git a/arch/arm64/kernel/rhi.c b/arch/arm64/kernel/rhi.c
new file mode 100644
index 000000000000..3685b50c2e94
--- /dev/null
+++ b/arch/arm64/kernel/rhi.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 ARM Ltd.
+ */
+
+#include <asm/memory.h>
+#include <asm/string.h>
+#include <asm/rsi.h>
+#include <asm/rhi.h>
+
+#include <linux/slab.h>
+
+long rhi_da_vdev_set_tdi_state(unsigned long guest_rid, unsigned long target_state)
+{
+	long ret;
+	struct rsi_host_call *rhi_call;
+
+	rhi_call = kmalloc(sizeof(struct rsi_host_call), GFP_KERNEL);
+	if (!rhi_call)
+		return -ENOMEM;
+
+	rhi_call->imm = 0;
+	rhi_call->gprs[0] = RHI_DA_VDEV_SET_TDI_STATE;
+	rhi_call->gprs[1] = guest_rid;
+	rhi_call->gprs[2] = target_state;
+
+	ret = rsi_host_call(virt_to_phys(rhi_call));
+	if (ret != RSI_SUCCESS)
+		ret =  -EIO;
+	else
+		ret = rhi_call->gprs[0];
+
+	kfree(rhi_call);
+	return ret;
+}
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
index 2c0190bcb2a9..de70fba09e92 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
@@ -222,11 +222,20 @@ static void cca_tsm_pci_remove(struct pci_tsm *tsm)
 
 static int cca_tsm_lock(struct pci_dev *pdev)
 {
-	unsigned long ret;
+	long ret;
+	int vdev_id = (pci_domain_nr(pdev->bus) << 16) |
+		PCI_DEVID(pdev->bus->number, pdev->devfn);
 
+	ret = rhi_da_vdev_set_tdi_state(vdev_id, RHI_DA_TDI_CONFIG_LOCKED);
+	if (ret) {
+		pci_err(pdev, "failed to TSM bind the device (%ld)\n", ret);
+		return -EIO;
+	}
+
+	/* This will be done by above rhi in later spec */
 	ret = rsi_device_lock(pdev);
 	if (ret) {
-		pci_err(pdev, "failed to lock the device (%lu)\n", ret);
+		pci_err(pdev, "failed to lock the device (%ld)\n", ret);
 		return -EIO;
 	}
 	return 0;
@@ -234,6 +243,15 @@ static int cca_tsm_lock(struct pci_dev *pdev)
 
 static void cca_tsm_unlock(struct pci_dev *pdev)
 {
+	long ret;
+	int vdev_id = (pci_domain_nr(pdev->bus) << 16) |
+		PCI_DEVID(pdev->bus->number, pdev->devfn);
+
+	ret = rhi_da_vdev_set_tdi_state(vdev_id, RHI_DA_TDI_CONFIG_UNLOCKED);
+	if (ret) {
+		pci_err(pdev, "failed to TSM unbind the device (%ld)\n", ret);
+		return;
+	}
 }
 
 static const struct pci_tsm_ops cca_pci_ops = {
diff --git a/drivers/virt/coco/arm-cca-host/arm-cca.c b/drivers/virt/coco/arm-cca-host/arm-cca.c
index 0807fcf8d222..18d0a627baa4 100644
--- a/drivers/virt/coco/arm-cca-host/arm-cca.c
+++ b/drivers/virt/coco/arm-cca-host/arm-cca.c
@@ -254,9 +254,13 @@ static struct pci_tdi *cca_tsm_bind(struct pci_dev *pdev, struct pci_dev *pf0_de
 static void cca_tsm_unbind(struct pci_tdi *tdi)
 {
 	struct realm *realm = &tdi->kvm->arch.realm;
-
+	/*
+	 * FIXME!!
+	 * All the related DEV RIPAS regions should be unmapped by now.
+	 * For now we handle them during stage2 teardown. There is no
+	 * bound IPA address available here. Possibly dmabuf can help
+	 */
 	rme_unbind_vdev(realm, tdi->pdev, tdi->pdev->tsm->dsm_dev);
-
 	module_put(THIS_MODULE);
 }
 
-- 
2.43.0