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@nvidia.com --- 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 + * + * 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; +}