On 31/10/24 08:35, Nicolin Chen wrote:
Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device (struct
device) against a vIOMMU (struct iommufd_viommu) object in a VM.
This vDEVICE object (and its structure) holds all the infos and attributes
in the VM, regarding the device related to the vIOMMU.
As an initial patch, add a per-vIOMMU virtual ID. This can be:
- Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
- Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
- Virtual RID on a nested Intel VT-D IOMMU, an index to a Context Table
Potentially, this vDEVICE structure would hold some vData for Confidential
Compute Architecture (CCA). Use this virtual ID to index an "vdevs" xarray
that belongs to a vIOMMU object.
Add a new ioctl for vDEVICE allocations. Since a vDEVICE is a connection
of a device object and an iommufd_viommu object, take two refcounts in the
ioctl handler.
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
drivers/iommu/iommufd/iommufd_private.h | 18 ++++++
include/linux/iommufd.h | 4 ++
include/uapi/linux/iommufd.h | 22 +++++++
drivers/iommu/iommufd/main.c | 6 ++
drivers/iommu/iommufd/viommu.c | 76 +++++++++++++++++++++++++
5 files changed, 126 insertions(+)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index e8f5ef550cc9..062656c19a07 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -507,8 +507,26 @@ static inline int iommufd_hwpt_replace_device(struct iommufd_device *idev,
return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
}
+static inline struct iommufd_viommu *
+iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
+{
+ return container_of(iommufd_get_object(ucmd->ictx, id,
+ IOMMUFD_OBJ_VIOMMU),
+ struct iommufd_viommu, obj);
+}
+
int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
void iommufd_viommu_destroy(struct iommufd_object *obj);
+int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
+void iommufd_vdevice_destroy(struct iommufd_object *obj);
+
+struct iommufd_vdevice {
+ struct iommufd_object obj;
+ struct iommufd_ctx *ictx;
+ struct iommufd_viommu *viommu;
+ struct device *dev;
+ u64 id; /* per-vIOMMU virtual ID */
+};
#ifdef CONFIG_IOMMUFD_TEST
int iommufd_test(struct iommufd_ucmd *ucmd);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index f03c75410938..ee58c5c573ec 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -10,6 +10,7 @@
#include <linux/errno.h>
#include <linux/refcount.h>
#include <linux/types.h>
+#include <linux/xarray.h>
struct device;
struct file;
@@ -31,6 +32,7 @@ enum iommufd_object_type {
IOMMUFD_OBJ_ACCESS,
IOMMUFD_OBJ_FAULT,
IOMMUFD_OBJ_VIOMMU,
+ IOMMUFD_OBJ_VDEVICE,
#ifdef CONFIG_IOMMUFD_TEST
IOMMUFD_OBJ_SELFTEST,
#endif
@@ -89,6 +91,8 @@ struct iommufd_viommu {
const struct iommufd_viommu_ops *ops;
+ struct xarray vdevs;
+
unsigned int type;
};
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index a498d4838f9a..9b5236004b8e 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -53,6 +53,7 @@ enum {
IOMMUFD_CMD_FAULT_QUEUE_ALLOC = 0x8e,
IOMMUFD_CMD_IOAS_MAP_FILE = 0x8f,
IOMMUFD_CMD_VIOMMU_ALLOC = 0x90,
+ IOMMUFD_CMD_VDEVICE_ALLOC = 0x91,
};
/**
@@ -864,4 +865,25 @@ struct iommu_viommu_alloc {
__u32 out_viommu_id;
};
#define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
+
+/**
+ * struct iommu_vdevice_alloc - ioctl(IOMMU_VDEVICE_ALLOC)
+ * @size: sizeof(struct iommu_vdevice_alloc)
+ * @viommu_id: vIOMMU ID to associate with the virtual device
+ * @dev_id: The physical device to allocate a virtual instance on the vIOMMU
+ * @out_vdevice_id: Object handle for the vDevice. Pass to IOMMU_DESTORY
+ * @virt_id: Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID
+ * of AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
So it is one vdevice per a passed through device (say, a network
adapter), right? I am asking as there are passed through devices and
IOMMU devices, and (at least on AMD) IOMMUs look like PCI devices, both
in hosts and guests. For example, from the above: "@dev_id: The physical
device ..." - both a network card and IOMMU are physical, so dev_id is a
NIC or IOMMU? I assume that шы a NIC (but it is a source of constant
confusion).
Is there any plan to add guest device BDFn as well, or I can add one
here for my TEE-IO exercise, if it is the right place? It is the same as
vDeviceID for AMD but I am not sure about the others, hence the
question. Thanks,
+ *
+ * Allocate a virtual device instance (for a physical device) against a vIOMMU.
+ * This instance holds the device's information (related to its vIOMMU) in a VM.
+ */
+struct iommu_vdevice_alloc {
+ __u32 size;
+ __u32 viommu_id;
+ __u32 dev_id;
+ __u32 out_vdevice_id;
+ __aligned_u64 virt_id;
+};
+#define IOMMU_VDEVICE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VDEVICE_ALLOC)
#endif
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index cc514f9bc3e6..d735fe04197f 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -308,6 +308,7 @@ union ucmd_buffer {
struct iommu_option option;
struct iommu_vfio_ioas vfio_ioas;
struct iommu_viommu_alloc viommu;
+ struct iommu_vdevice_alloc vdev;
#ifdef CONFIG_IOMMUFD_TEST
struct iommu_test_cmd test;
#endif
@@ -363,6 +364,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
__reserved),
IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
struct iommu_viommu_alloc, out_viommu_id),
+ IOCTL_OP(IOMMU_VDEVICE_ALLOC, iommufd_vdevice_alloc_ioctl,
+ struct iommu_vdevice_alloc, virt_id),
#ifdef CONFIG_IOMMUFD_TEST
IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
#endif
@@ -501,6 +504,9 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
[IOMMUFD_OBJ_VIOMMU] = {
.destroy = iommufd_viommu_destroy,
},
+ [IOMMUFD_OBJ_VDEVICE] = {
+ .destroy = iommufd_vdevice_destroy,
+ },
#ifdef CONFIG_IOMMUFD_TEST
[IOMMUFD_OBJ_SELFTEST] = {
.destroy = iommufd_selftest_destroy,
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 888239b78667..c82b4a07a4b1 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -11,6 +11,7 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
if (viommu->ops && viommu->ops->destroy)
viommu->ops->destroy(viommu);
refcount_dec(&viommu->hwpt->common.obj.users);
+ xa_destroy(&viommu->vdevs);
}
int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
@@ -53,6 +54,7 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
goto out_put_hwpt;
}
+ xa_init(&viommu->vdevs);
viommu->type = cmd->type;
viommu->ictx = ucmd->ictx;
viommu->hwpt = hwpt_paging;
@@ -79,3 +81,77 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
iommufd_put_object(ucmd->ictx, &idev->obj);
return rc;
}
+
+void iommufd_vdevice_destroy(struct iommufd_object *obj)
+{
+ struct iommufd_vdevice *vdev =
+ container_of(obj, struct iommufd_vdevice, obj);
+ struct iommufd_viommu *viommu = vdev->viommu;
+
+ /* xa_cmpxchg is okay to fail if alloc returned -EEXIST previously */
+ xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
+ refcount_dec(&viommu->obj.users);
+ put_device(vdev->dev);
+}
+
+int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_vdevice_alloc *cmd = ucmd->cmd;
+ struct iommufd_vdevice *vdev, *curr;
+ struct iommufd_viommu *viommu;
+ struct iommufd_device *idev;
+ u64 virt_id = cmd->virt_id;
+ int rc = 0;
+
+ /* virt_id indexes an xarray */
+ if (virt_id > ULONG_MAX)
+ return -EINVAL;
+
+ viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+ if (IS_ERR(viommu))
+ return PTR_ERR(viommu);
+
+ idev = iommufd_get_device(ucmd, cmd->dev_id);
+ if (IS_ERR(idev)) {
+ rc = PTR_ERR(idev);
+ goto out_put_viommu;
+ }
+
+ if (viommu->iommu_dev != __iommu_get_iommu_dev(idev->dev)) {
+ rc = -EINVAL;
+ goto out_put_idev;
+ }
+
+ vdev = iommufd_object_alloc(ucmd->ictx, vdev, IOMMUFD_OBJ_VDEVICE);
+ if (IS_ERR(vdev)) {
+ rc = PTR_ERR(vdev);
+ goto out_put_idev;
+ }
+
+ vdev->id = virt_id;
+ vdev->dev = idev->dev;
+ get_device(idev->dev);
+ vdev->viommu = viommu;
+ refcount_inc(&viommu->obj.users);
+
+ curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
+ if (curr) {
+ rc = xa_err(curr) ?: -EEXIST;
+ goto out_abort;
+ }
+
+ cmd->out_vdevice_id = vdev->obj.id;
+ rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+ if (rc)
+ goto out_abort;
+ iommufd_object_finalize(ucmd->ictx, &vdev->obj);
+ goto out_put_idev;
+
+out_abort:
+ iommufd_object_abort_and_destroy(ucmd->ictx, &vdev->obj);
+out_put_idev:
+ iommufd_put_object(ucmd->ictx, &idev->obj);
+out_put_viommu:
+ iommufd_put_object(ucmd->ictx, &viommu->obj);
+ return rc;
+}
--
Alexey
