"Dan Williams (nvidia)" [off-list ref] writes:

Aneesh Kumar K.V (Arm) wrote:

quoted

Register the TSM callback when the DA feature is supported by KVM.

This driver handles IDE stream setup for both the root port and PCIe
endpoints. Root port IDE stream enablement itself is managed by RMM.

In addition, the driver registers pci_tsm_ops with the TSM subsystem.

Do you want to call out that this is an infrastructure / scaffolding
patch that only handles the PCI-TSM skeleton. The CCA meat comes later,
in particular IDE key management. Tell a bit more of the story 

Otherwise, mostly looks good.

Sure, I’ll update the commit message.

Minor comments below...

quoted

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/rmi_smc.h         |   2 +
 drivers/firmware/smccc/rmm.c             |  12 ++
 drivers/firmware/smccc/rmm.h             |   8 +
 drivers/firmware/smccc/smccc.c           |   1 +
 drivers/virt/coco/Kconfig                |   2 +
 drivers/virt/coco/Makefile               |   1 +
 drivers/virt/coco/arm-cca-host/Kconfig   |  19 ++
 drivers/virt/coco/arm-cca-host/Makefile  |   5 +
 drivers/virt/coco/arm-cca-host/arm-cca.c | 225 +++++++++++++++++++++++
 drivers/virt/coco/arm-cca-host/rmi-da.h  |  46 +++++
 10 files changed, 321 insertions(+)
 create mode 100644 drivers/virt/coco/arm-cca-host/Kconfig
 create mode 100644 drivers/virt/coco/arm-cca-host/Makefile
 create mode 100644 drivers/virt/coco/arm-cca-host/arm-cca.c
 create mode 100644 drivers/virt/coco/arm-cca-host/rmi-da.h

diff --git a/arch/arm64/include/asm/rmi_smc.h b/arch/arm64/include/asm/rmi_smc.h
index fa23818e1b4c..109d6cc6ef37 100644
--- a/arch/arm64/include/asm/rmi_smc.h
+++ b/arch/arm64/include/asm/rmi_smc.h

[..]

quoted

diff --git a/drivers/firmware/smccc/rmm.c b/drivers/firmware/smccc/rmm.c
index 2a6187df3285..7444cc3a588c 100644
--- a/drivers/firmware/smccc/rmm.c
+++ b/drivers/firmware/smccc/rmm.c

[..]

quoted

diff --git a/drivers/firmware/smccc/rmm.h b/drivers/firmware/smccc/rmm.h
index a47a650d4f51..37d0d95a099e 100644
--- a/drivers/firmware/smccc/rmm.h
+++ b/drivers/firmware/smccc/rmm.h

[..]

quoted

diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
index fc9b44b7c687..2bf2d59e686d 100644
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c

@@ -97,6 +97,7 @@ static int __init smccc_devices_init(void)
 		 * the required SMCCC function IDs at a supported revision.
 		 */
 		register_rsi_device(pdev);
+		register_rmi_device(pdev);
 	}

Would splitting the above three hunks make this series stand on its own
relative to the base CCA series? I assume likely not as soon as we get
to patch2.

Otherwise, just curious what your intended merge strategy is for this,
tsm.git or arm.git, and what help this needs?

[..]
snip code that looks good.

Yes, I’ll split this into a separate patch.

quoted

diff --git a/drivers/virt/coco/arm-cca-host/Makefile b/drivers/virt/coco/arm-cca-host/Makefile
new file mode 100644
index 000000000000..c236827f002c
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-host/Makefile

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+obj-$(CONFIG_ARM_CCA_HOST) += arm-cca-host.o
+
+arm-cca-host-y	+=  arm-cca.o

diff --git a/drivers/virt/coco/arm-cca-host/arm-cca.c b/drivers/virt/coco/arm-cca-host/arm-cca.c
new file mode 100644
index 000000000000..67f7e80106e8
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-host/arm-cca.c

@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2026 ARM Ltd.
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/pci-tsm.h>
+#include <linux/pci-ide.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/tsm.h>
+#include <linux/vmalloc.h>
+#include <linux/cleanup.h>
+
+#include "rmi-da.h"
+
+/* Total number of stream id supported at root port level */
+#define MAX_STREAM_ID	256
+
+static struct pci_tsm *cca_tsm_pci_probe(struct tsm_dev *tsm_dev, struct pci_dev *pdev)
+{
+	int ret;
+
+	if (!is_pci_tsm_pf0(pdev)) {
+		struct cca_host_fn_dsc *fn_dsc __free(kfree) =
+			kzalloc(sizeof(*fn_dsc), GFP_KERNEL);

kzalloc_obj(*fn_dsc)

quoted

+
+		if (!fn_dsc)
+			return NULL;
+
+		ret = pci_tsm_link_constructor(pdev, &fn_dsc->pci, tsm_dev);
+		if (ret)
+			return NULL;
+
+		return &no_free_ptr(fn_dsc)->pci;
+	}
+
+	if (!pdev->ide_cap)
+		return NULL;

Bailing early?

Maybe the RMM knows something about this device not needing IDE? I have
a similar question in patch2 around trusted sources for whether a device
is internal or not.

Yes. This get updated later in
https://lore.kernel.org/all/20260427065121.916615-14-aneesh.kumar@kernel.org (local)

quoted

+
+	struct cca_host_pf0_ep_dsc *pf0_ep_dsc __free(kfree) =
+		kzalloc(sizeof(*pf0_ep_dsc), GFP_KERNEL);
+	if (!pf0_ep_dsc)
+		return NULL;
+
+	ret = pci_tsm_pf0_constructor(pdev, &pf0_ep_dsc->pci, tsm_dev);
+	if (ret)
+		return NULL;
+
+	pci_dbg(pdev, "tsm enabled\n");
+	return &no_free_ptr(pf0_ep_dsc)->pci.base_tsm;
+}
+
+static void cca_tsm_pci_remove(struct pci_tsm *tsm)
+{
+	struct pci_dev *pdev = tsm->pdev;
+
+	if (is_pci_tsm_pf0(pdev)) {
+		struct cca_host_pf0_ep_dsc *pf0_ep_dsc = to_cca_pf0_ep_dsc(pdev);
+
+		pci_tsm_pf0_destructor(&pf0_ep_dsc->pci);
+		kfree(pf0_ep_dsc);
+	} else {
+		kfree(to_cca_fn_dsc(pdev));
+	}
+}
+
+/* For now global for simplicity. Protected by pci_tsm_rwsem */
+static DECLARE_BITMAP(cca_stream_ids, MAX_STREAM_ID);
+static int alloc_stream_id(struct pci_host_bridge *hb)
+{
+	int stream_id;
+
+redo_alloc:
+	stream_id = find_first_zero_bit(cca_stream_ids, MAX_STREAM_ID);
+	if (stream_id == MAX_STREAM_ID)
+		return stream_id;
+
+	if (ida_exists(&hb->ide_stream_ids_ida, stream_id)) {
+		/* mark the stream allocated in the global bitmap. */
+		set_bit(stream_id, cca_stream_ids);
+		goto redo_alloc;
+	}
+	return stream_id;

Is 256 total an RMM limit, and/or does it require globally unique
stream-ids? If not you could do what SEV-TIO does and just set stream-id
== stream-index.

Yes, I’ll switch to that.

quoted

+}
+
+static inline bool cca_pdev_need_sel_ide_streams(struct pci_dev *pdev)
+{
+	return pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT;
+}
+
+static int cca_tsm_connect(struct pci_dev *pdev)
+{
+	struct pci_dev *rp = pcie_find_root_port(pdev);
+	struct cca_host_pf0_ep_dsc *pf0_ep_dsc;
+	struct pci_ide *ide;
+	int ret, stream_id = 0;
+
+	/* Only function 0 supports connect in host */
+	if (WARN_ON(!is_pci_tsm_pf0(pdev)))
+		return -EIO;
+
+	pf0_ep_dsc = to_cca_pf0_ep_dsc(pdev);
+	if (cca_pdev_need_sel_ide_streams(pdev)) {
+		/* Allocate stream id */
+		stream_id = alloc_stream_id(pci_find_host_bridge(pdev->bus));
+		if (stream_id == MAX_STREAM_ID)
+			return -EBUSY;
+		set_bit(stream_id, cca_stream_ids);
+
+		ide = pci_ide_stream_alloc(pdev);
+		if (!ide) {
+			ret = -ENOMEM;
+			goto err_stream_alloc;
+		}
+
+		pf0_ep_dsc->sel_stream = ide;
+		ide->stream_id = stream_id;
+		ret = pci_ide_stream_register(ide);
+		if (ret)
+			goto err_stream;
+		/*
+		 * Configure IDE capability for target device
+		 *
+		 * Some test devices work only with DEFAULT_STREAM enabled.
+		 * For simplicity, enable DEFAULT_STREAM for all devices. A
+		 * future decent solution may be to have a quirk table to
+		 * specify which devices need DEFAULT_STREAM.
+		 */
+		ide->partner[PCI_IDE_EP].default_stream = 1;
+		pci_ide_stream_setup(pdev, ide);
+		pci_ide_stream_setup(rp, ide);
+
+		ret = tsm_ide_stream_register(ide);
+		if (ret)
+			goto err_tsm;
+
+		/*
+		 * Once ide is setup, enable the stream at the endpoint
+		 * Root port will be done by RMM
+		 */
+		pci_ide_stream_enable(pdev, ide);

The end point of these patches follows the spec recommendation of
delaying enable until after key programming.

quoted

+	}
+	return 0;

Should this be making security claims to userspace without taking any
action for non-endpoint devices that happen to be passed in?

Thinking about a bisection case this should either fail here, print a
message that is removed in the final enabling patch, or do the
__maybe_unused arrangement to land all the CCA bits first and then do
this hookup. Up to you.

Will do the latter. ie, I’ll call tsm_register() only in the final
patch.

-aneesh