Re: [PATCH v5 5/5] iommufd/vdevice: add TSM request ioctl
From: Alexey Kardashevskiy
Date: Tue May 26 2026 - 20:18:20 EST
On 26/5/26 01:48, Aneesh Kumar K.V (Arm) wrote:
Add IOMMU_VDEVICE_TSM_REQUEST for issuing TSM guest request/response
transactions against an iommufd vdevice.
The ioctl takes a vdevice_id plus request/response user buffers and length
fields, and forwards the request through tsm_guest_req() to the PCI TSM
backend. This provides the host-side passthrough path used by CoCo guests
for TSM device attestation and acceptance flows after the device has been
bound to TSM.
Also add the supporting tsm_guest_req() helper and associated TSM core
interface definitions.
Based on changes from: Alexey Kardashevskiy <aik@xxxxxxx>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
---
drivers/iommu/iommufd/iommufd_private.h | 6 ++
drivers/iommu/iommufd/main.c | 3 +
drivers/iommu/iommufd/tsm.c | 68 +++++++++++++++++++++
drivers/virt/coco/tsm-core.c | 39 ++++++++++++
include/linux/pci-tsm.h | 9 +--
include/linux/tsm.h | 25 ++++++++
include/uapi/linux/iommufd.h | 80 +++++++++++++++++++++++++
7 files changed, 226 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 8eea0c2c332b..0080895e9e92 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -701,11 +701,17 @@ int iommufd_hw_queue_alloc_ioctl(struct iommufd_ucmd *ucmd);
void iommufd_hw_queue_destroy(struct iommufd_object *obj);
#ifdef CONFIG_TSM
int iommufd_vdevice_tsm_op_ioctl(struct iommufd_ucmd *ucmd);
+int iommufd_vdevice_tsm_req_ioctl(struct iommufd_ucmd *ucmd);
#else
static inline int iommufd_vdevice_tsm_op_ioctl(struct iommufd_ucmd *ucmd)
{
return -EOPNOTSUPP;
}
+
+static inline int iommufd_vdevice_tsm_req_ioctl(struct iommufd_ucmd *ucmd)
+{
+ return -EOPNOTSUPP;
+}
#endif
static inline struct iommufd_vdevice *
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index d73e6b391c6f..5f49b546ec92 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -433,6 +433,7 @@ union ucmd_buffer {
struct iommu_vfio_ioas vfio_ioas;
struct iommu_viommu_alloc viommu;
struct iommu_vdevice_tsm_op tsm_op;
+ struct iommu_vdevice_tsm_req tsm_req;
#ifdef CONFIG_IOMMUFD_TEST
struct iommu_test_cmd test;
#endif
@@ -496,6 +497,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
struct iommu_viommu_alloc, out_viommu_id),
IOCTL_OP(IOMMU_VDEVICE_TSM_OP, iommufd_vdevice_tsm_op_ioctl,
struct iommu_vdevice_tsm_op, vdevice_id),
+ IOCTL_OP(IOMMU_VDEVICE_TSM_REQ, iommufd_vdevice_tsm_req_ioctl,
+ struct iommu_vdevice_tsm_req, resp_uptr),
#ifdef CONFIG_IOMMUFD_TEST
IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
#endif
diff --git a/drivers/iommu/iommufd/tsm.c b/drivers/iommu/iommufd/tsm.c
index 09ee668dbed9..342fbdb6a6b9 100644
--- a/drivers/iommu/iommufd/tsm.c
+++ b/drivers/iommu/iommufd/tsm.c
@@ -60,3 +60,71 @@ int iommufd_vdevice_tsm_op_ioctl(struct iommufd_ucmd *ucmd)
iommufd_put_object(ucmd->ictx, &vdev->obj);
return rc;
}
+
+static bool iommufd_vdevice_tsm_req_scope_valid(u32 scope)
+{
+ if (scope > IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_LAST)
+ return false;
+
+ switch (scope) {
+ case IOMMU_VDEVICE_TSM_REQ_PCI_INFO:
+ case IOMMU_VDEVICE_TSM_REQ_PCI_STATE_CHANGE:
+ case IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_READ:
+ case IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_WRITE:
This scope thing still needs clarification.
I have 3 types of requests to fit here, all go via VM -> KVM -> QEMU -> IOMMUFD -> TSM.
1) bind/unbind TDI <- moves to CONFIG_LOCKED, this is "OP";
2) start/stop TDI <- moves to RUN, this is "GR"? Right now I route it via "OP";
3) enable/disable MMIO/DMA <- no TDI state change, this is "GR" but which scope is it here?
thanks,
+ return true;
+ default:
+ return false;
+ }
+}
+
+/**
+ * iommufd_vdevice_tsm_req_ioctl - Forward TSM requests
+ * @ucmd: user command data for IOMMU_VDEVICE_TSM_REQ
+ *
+ * Resolve @iommu_vdevice_tsm_req::vdevice_id to a vdevice and pass the
+ * request/response buffers to the TSM core.
+ *
+ * Return:
+ * -errno on error.
+ * positive residue if response/request bytes were left unconsumed.
+ * if response buffer is provided, residue indicates the number of bytes
+ * not used in response buffer
+ * if there is no response buffer, residue indicates the number of bytes
+ * not consumed in req buffer
+ * 0 otherwise.
+ */
+int iommufd_vdevice_tsm_req_ioctl(struct iommufd_ucmd *ucmd)
+{
+ int rc;
+ struct iommufd_vdevice *vdev;
+ struct iommu_vdevice_tsm_req *cmd = ucmd->cmd;
+ struct tsm_guest_req_info info = {
+ .scope = cmd->scope,
+ .req = {
+ .user = u64_to_user_ptr(cmd->req_uptr),
+ .is_kernel = false,
+ },
+ .req_len = cmd->req_len,
+ .resp = {
+ .user = u64_to_user_ptr(cmd->resp_uptr),
+ .is_kernel = false,
+ },
+ .resp_len = cmd->resp_len,
+ };
+
+ if (cmd->__reserved)
+ return -EOPNOTSUPP;
+
+ if (!iommufd_vdevice_tsm_req_scope_valid(cmd->scope))
+ return -EINVAL;
+
+ vdev = iommufd_get_vdevice(ucmd->ictx, cmd->vdevice_id);
+ if (IS_ERR(vdev))
+ return PTR_ERR(vdev);
+
+ rc = tsm_guest_req(vdev->idev->dev, &info);
+
+ /* No inline response, hence we don't need to copy the response */
+ iommufd_put_object(ucmd->ictx, &vdev->obj);
+ return rc;
+}
diff --git a/drivers/virt/coco/tsm-core.c b/drivers/virt/coco/tsm-core.c
index 3870d08ffe0d..c24886851f9e 100644
--- a/drivers/virt/coco/tsm-core.c
+++ b/drivers/virt/coco/tsm-core.c
@@ -8,6 +8,7 @@
#include <linux/module.h>
#include <linux/cleanup.h>
#include <linux/pci-tsm.h>
+#include <uapi/linux/iommufd.h>
static void tsm_release(struct device *);
static const struct class tsm_class = {
@@ -127,6 +128,44 @@ int tsm_unbind(struct device *dev)
}
EXPORT_SYMBOL_GPL(tsm_unbind);
+static int tsm_pci_req_scope(u32 scope, enum pci_tsm_req_scope *pci_scope)
+{
+ switch (scope) {
+ case IOMMU_VDEVICE_TSM_REQ_PCI_INFO:
+ *pci_scope = PCI_TSM_REQ_INFO;
+ return 0;
+ case IOMMU_VDEVICE_TSM_REQ_PCI_STATE_CHANGE:
+ *pci_scope = PCI_TSM_REQ_STATE_CHANGE;
+ return 0;
+ case IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_READ:
+ *pci_scope = PCI_TSM_REQ_DEBUG_READ;
+ return 0;
+ case IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_WRITE:
+ *pci_scope = PCI_TSM_REQ_DEBUG_WRITE;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+ssize_t tsm_guest_req(struct device *dev, struct tsm_guest_req_info *info)
+{
+ int ret;
+ enum pci_tsm_req_scope pci_scope;
+
+ if (!dev_is_pci(dev))
+ return -EINVAL;
+
+ ret = tsm_pci_req_scope(info->scope, &pci_scope);
+ if (ret)
+ return ret;
+
+ return pci_tsm_guest_req(to_pci_dev(dev), pci_scope, info->req,
+ info->req_len, info->resp, info->resp_len,
+ NULL);
+}
+EXPORT_SYMBOL_GPL(tsm_guest_req);
+
static void tsm_release(struct device *dev)
{
struct tsm_dev *tsm_dev = container_of(dev, typeof(*tsm_dev), dev);
diff --git a/include/linux/pci-tsm.h b/include/linux/pci-tsm.h
index a6435aba03f9..ec2236a7a279 100644
--- a/include/linux/pci-tsm.h
+++ b/include/linux/pci-tsm.h
@@ -4,6 +4,7 @@
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/sockptr.h>
+#include <uapi/linux/iommufd.h>
struct pci_tsm;
struct tsm_dev;
@@ -173,7 +174,7 @@ enum pci_tsm_req_scope {
* typical TDISP collateral information like Device Interface Reports.
* No device secrets are permitted, and no device state is changed.
*/
- PCI_TSM_REQ_INFO = 0,
+ PCI_TSM_REQ_INFO = IOMMU_VDEVICE_TSM_REQ_PCI_INFO,
/**
* @PCI_TSM_REQ_STATE_CHANGE: Request to change the TDISP state from
* UNLOCKED->LOCKED, LOCKED->RUN, or other architecture specific state
@@ -181,14 +182,14 @@ enum pci_tsm_req_scope {
* to TDISP) device / host state, configuration, or data change is
* permitted.
*/
- PCI_TSM_REQ_STATE_CHANGE = 1,
+ PCI_TSM_REQ_STATE_CHANGE = IOMMU_VDEVICE_TSM_REQ_PCI_STATE_CHANGE,
/**
* @PCI_TSM_REQ_DEBUG_READ: Read-only request for debug information
*
* A method to facilitate TVM information retrieval outside of typical
* TDISP operational requirements. No device secrets are permitted.
*/
- PCI_TSM_REQ_DEBUG_READ = 2,
+ PCI_TSM_REQ_DEBUG_READ = IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_READ,
/**
* @PCI_TSM_REQ_DEBUG_WRITE: Device state changes for debug purposes
*
@@ -196,7 +197,7 @@ enum pci_tsm_req_scope {
* the TDISP operational model. If allowed, requires CAP_SYS_RAW_IO, and
* will taint the kernel.
*/
- PCI_TSM_REQ_DEBUG_WRITE = 3,
+ PCI_TSM_REQ_DEBUG_WRITE = IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_WRITE,
};
#ifdef CONFIG_PCI_TSM
diff --git a/include/linux/tsm.h b/include/linux/tsm.h
index 7b6df827321b..6101a2a1db61 100644
--- a/include/linux/tsm.h
+++ b/include/linux/tsm.h
@@ -6,6 +6,7 @@
#include <linux/types.h>
#include <linux/uuid.h>
#include <linux/device.h>
+#include <linux/sockptr.h>
#define TSM_REPORT_INBLOB_MAX 64
#define TSM_REPORT_OUTBLOB_MAX SZ_16M
@@ -128,6 +129,23 @@ struct kvm;
#ifdef CONFIG_TSM
int tsm_bind(struct device *dev, struct kvm *kvm, u64 tdi_id);
int tsm_unbind(struct device *dev);
+
+/**
+ * struct tsm_guest_req_info - parameter for tsm_guest_req()
+ * @scope: iommufd allocated scope for tsm guest request
+ * @req: request data buffer filled by guest
+ * @req_len: the size of @req filled by guest
+ * @resp: response data buffer filled by host
+ * @resp_len: the size of @resp buffer filled by guest
+ */
+struct tsm_guest_req_info {
+ u32 scope;
+ sockptr_t req;
+ size_t req_len;
+ sockptr_t resp;
+ size_t resp_len;
+};
+ssize_t tsm_guest_req(struct device *dev, struct tsm_guest_req_info *info);
#else
static inline int tsm_bind(struct device *dev, struct kvm *kvm, u64 tdi_id)
{
@@ -138,6 +156,13 @@ static inline int tsm_unbind(struct device *dev)
{
return 0;
}
+
+struct tsm_guest_req_info;
+static inline ssize_t tsm_guest_req(struct device *dev,
+ struct tsm_guest_req_info *info)
+{
+ return -EINVAL;
+}
#endif
#endif /* __TSM_H */
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 66398efa31d1..7953e99a9671 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -58,6 +58,7 @@ enum {
IOMMUFD_CMD_VEVENTQ_ALLOC = 0x93,
IOMMUFD_CMD_HW_QUEUE_ALLOC = 0x94,
IOMMUFD_CMD_VDEVICE_TSM_OP = 0x95,
+ IOMMUFD_CMD_VDEVICE_TSM_REQ = 0x96,
};
/**
@@ -1373,4 +1374,83 @@ struct iommu_hw_queue_alloc {
__aligned_u64 length;
};
#define IOMMU_HW_QUEUE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HW_QUEUE_ALLOC)
+
+/*
+ * TSM request scope values are allocated by iommufd. Each device-bus transport
+ * gets a range from this number space.
+ */
+#define IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_BASE 0
+
+enum iommu_vdevice_tsm_req_scope {
+ /*
+ * Read-only, without side effects, request for typical TDISP
+ * collateral information like Device Interface Reports. No device
+ * secrets are permitted, and no device state is changed.
+ */
+ IOMMU_VDEVICE_TSM_REQ_PCI_INFO =
+ IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_BASE,
+ /*
+ * Request to change the TDISP state from UNLOCKED->LOCKED,
+ * LOCKED->RUN, or other architecture specific state changes to
+ * support those transitions for a TDI. No other device or host state,
+ * configuration, or data change is permitted.
+ */
+ IOMMU_VDEVICE_TSM_REQ_PCI_STATE_CHANGE =
+ IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_BASE + 1,
+ /*
+ * Read-only request for debug information outside of typical TDISP
+ * operational requirements. No device secrets are permitted.
+ */
+ IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_READ =
+ IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_BASE + 2,
+ /*
+ * Device state changes for debug purposes. The request may affect the
+ * operational state of the device outside of the TDISP operational
+ * model. If allowed, this requires CAP_SYS_RAW_IO and taints the
+ * kernel.
+ */
+ IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_WRITE =
+ IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_BASE + 3,
+ IOMMU_VDEVICE_TSM_REQ_SCOPE_PCI_LAST =
+ IOMMU_VDEVICE_TSM_REQ_PCI_DEBUG_WRITE,
+};
+
+/**
+ * struct iommu_vdevice_tsm_req - ioctl(IOMMU_VDEVICE_TSM_REQ)
+ * @size: sizeof(struct iommu_vdevice_tsm_req)
+ * @vdevice_id: vDevice ID the guest request is for
+ * @scope: One of enum iommu_vdevice_tsm_req_scope
+ * @req_len: Size in bytes of the input payload at @req_uptr
+ * @resp_len: Size in bytes of the output buffer at @resp_uptr
+ * @__reserved: Must be 0
+ * @req_uptr: Userspace pointer to the guest-provided request payload
+ * @resp_uptr: Userspace pointer to the guest response buffer
+ *
+ * Forward a TSM request to the TSM bound vDevice. This is intended for
+ * guest TSM/TDISP message transport where the host kernel only marshals
+ * bytes between userspace and the TSM implementation.
+ *
+ * Requests outside the iommufd allocated scope values are rejected. Lower
+ * layers may reject scope values that are valid in the global iommufd
+ * namespace, but not permitted for a specific bus.
+ *
+ * The request payload is read from @req_uptr/@req_len. If a response is
+ * expected, userspace provides @resp_uptr/@resp_len as writable storage for
+ * response bytes returned by the TSM path.
+ *
+ * The ioctl is only suitable for commands and results that the host kernel
+ * has no use, the host is only facilitating guest to TSM communication.
+ */
+struct iommu_vdevice_tsm_req {
+ __u32 size;
+ __u32 vdevice_id;
+ __u32 scope;
+ __u32 req_len;
+ __u32 resp_len;
+ __u32 __reserved;
+ __aligned_u64 req_uptr;
+ __aligned_u64 resp_uptr;
+};
+
+#define IOMMU_VDEVICE_TSM_REQ _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VDEVICE_TSM_REQ)
#endif
--
Alexey