Commit 0ce5c247 authored by Nicolin Chen's avatar Nicolin Chen Committed by Jason Gunthorpe
Browse files

iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl 

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.

Link: https://patch.msgid.link/r/cda8fd2263166e61b8191a3b3207e0d2b08545bf.1730836308.git.nicolinc@nvidia.com


Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 87210b10

drivers/iommu/iommufd/iommufd_private.h

+18 −0
Original line number Diff line number Diff line
@@ -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);

drivers/iommu/iommufd/main.c

+6 −0
Original line number Diff line number Diff line
@@ -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,

drivers/iommu/iommufd/viommu.c

+76 −0
Original line number Diff line number Diff line
@@ -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 failed xa_cmpxchg 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;

}

include/linux/iommufd.h

+4 −0
Original line number Diff line number Diff line
@@ -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;

};

include/uapi/linux/iommufd.h

+22 −0
Original line number Diff line number Diff line
@@ -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