Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
iommu: Introduce a replace API for device pasid
Provide a high-level API to allow replacements of one domain with another
for specific pasid of a device. This is similar to
iommu_replace_group_handle() and it is expected to be used only by IOMMUFD.
Link: https://patch.msgid.link/r/20250321171940.7213-3-yi.l.liu@intel.com
Co-developed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
authored by
Yi Liu
and committed by
Jason Gunthorpe
8a9e1e77
ada14b9f
+114
-4
+3
drivers/iommu/iommu-priv.h
+3
drivers/iommu/iommu-priv.h
+111
-4
drivers/iommu/iommu.c
+111
-4
drivers/iommu/iommu.c
···
514
514
dev_iommu_free(dev);
515
515
}
516
516
517
+
static struct iommu_domain *pasid_array_entry_to_domain(void *entry)
518
+
{
519
+
if (xa_pointer_tag(entry) == IOMMU_PASID_ARRAY_DOMAIN)
520
+
return xa_untag_pointer(entry);
521
+
return ((struct iommu_attach_handle *)xa_untag_pointer(entry))->domain;
522
+
}
523
+
517
524
DEFINE_MUTEX(iommu_probe_device_lock);
518
525
519
526
static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
···
3331
3324
}
3332
3325
3333
3326
static int __iommu_set_group_pasid(struct iommu_domain *domain,
3334
-
struct iommu_group *group, ioasid_t pasid)
3327
+
struct iommu_group *group, ioasid_t pasid,
3328
+
struct iommu_domain *old)
3335
3329
{
3336
3330
struct group_device *device, *last_gdev;
3337
3331
int ret;
3338
3332
3339
3333
for_each_group_device(group, device) {
3340
3334
ret = domain->ops->set_dev_pasid(domain, device->dev,
3341
-
pasid, NULL);
3335
+
pasid, old);
3342
3336
if (ret)
3343
3337
goto err_revert;
3344
3338
}
···
3351
3343
for_each_group_device(group, device) {
3352
3344
if (device == last_gdev)
3353
3345
break;
3354
-
iommu_remove_dev_pasid(device->dev, pasid, domain);
3346
+
/*
3347
+
* If no old domain, undo the succeeded devices/pasid.
3348
+
* Otherwise, rollback the succeeded devices/pasid to the old
3349
+
* domain. And it is a driver bug to fail attaching with a
3350
+
* previously good domain.
3351
+
*/
3352
+
if (!old || WARN_ON(old->ops->set_dev_pasid(old, device->dev,
3353
+
pasid, domain)))
3354
+
iommu_remove_dev_pasid(device->dev, pasid, domain);
3355
3355
}
3356
3356
return ret;
3357
3357
}
···
3428
3412
if (ret)
3429
3413
goto out_unlock;
3430
3414
3431
-
ret = __iommu_set_group_pasid(domain, group, pasid);
3415
+
ret = __iommu_set_group_pasid(domain, group, pasid, NULL);
3432
3416
if (ret) {
3433
3417
xa_release(&group->pasid_array, pasid);
3434
3418
goto out_unlock;
···
3448
3432
return ret;
3449
3433
}
3450
3434
EXPORT_SYMBOL_GPL(iommu_attach_device_pasid);
3435
+
3436
+
/**
3437
+
* iommu_replace_device_pasid - Replace the domain that a specific pasid
3438
+
* of the device is attached to
3439
+
* @domain: the new iommu domain
3440
+
* @dev: the attached device.
3441
+
* @pasid: the pasid of the device.
3442
+
* @handle: the attach handle.
3443
+
*
3444
+
* This API allows the pasid to switch domains. The @pasid should have been
3445
+
* attached. Otherwise, this fails. The pasid will keep the old configuration
3446
+
* if replacement failed.
3447
+
*
3448
+
* Caller should always provide a new handle to avoid race with the paths
3449
+
* that have lockless reference to handle if it intends to pass a valid handle.
3450
+
*
3451
+
* Return 0 on success, or an error.
3452
+
*/
3453
+
int iommu_replace_device_pasid(struct iommu_domain *domain,
3454
+
struct device *dev, ioasid_t pasid,
3455
+
struct iommu_attach_handle *handle)
3456
+
{
3457
+
/* Caller must be a probed driver on dev */
3458
+
struct iommu_group *group = dev->iommu_group;
3459
+
struct iommu_attach_handle *entry;
3460
+
struct iommu_domain *curr_domain;
3461
+
void *curr;
3462
+
int ret;
3463
+
3464
+
if (!group)
3465
+
return -ENODEV;
3466
+
3467
+
if (!domain->ops->set_dev_pasid)
3468
+
return -EOPNOTSUPP;
3469
+
3470
+
if (dev_iommu_ops(dev) != domain->owner ||
3471
+
pasid == IOMMU_NO_PASID || !handle)
3472
+
return -EINVAL;
3473
+
3474
+
mutex_lock(&group->mutex);
3475
+
entry = iommu_make_pasid_array_entry(domain, handle);
3476
+
curr = xa_cmpxchg(&group->pasid_array, pasid, NULL,
3477
+
XA_ZERO_ENTRY, GFP_KERNEL);
3478
+
if (xa_is_err(curr)) {
3479
+
ret = xa_err(curr);
3480
+
goto out_unlock;
3481
+
}
3482
+
3483
+
/*
3484
+
* No domain (with or without handle) attached, hence not
3485
+
* a replace case.
3486
+
*/
3487
+
if (!curr) {
3488
+
xa_release(&group->pasid_array, pasid);
3489
+
ret = -EINVAL;
3490
+
goto out_unlock;
3491
+
}
3492
+
3493
+
/*
3494
+
* Reusing handle is problematic as there are paths that refers
3495
+
* the handle without lock. To avoid race, reject the callers that
3496
+
* attempt it.
3497
+
*/
3498
+
if (curr == entry) {
3499
+
WARN_ON(1);
3500
+
ret = -EINVAL;
3501
+
goto out_unlock;
3502
+
}
3503
+
3504
+
curr_domain = pasid_array_entry_to_domain(curr);
3505
+
ret = 0;
3506
+
3507
+
if (curr_domain != domain) {
3508
+
ret = __iommu_set_group_pasid(domain, group,
3509
+
pasid, curr_domain);
3510
+
if (ret)
3511
+
goto out_unlock;
3512
+
}
3513
+
3514
+
/*
3515
+
* The above xa_cmpxchg() reserved the memory, and the
3516
+
* group->mutex is held, this cannot fail.
3517
+
*/
3518
+
WARN_ON(xa_is_err(xa_store(&group->pasid_array,
3519
+
pasid, entry, GFP_KERNEL)));
3520
+
3521
+
out_unlock:
3522
+
mutex_unlock(&group->mutex);
3523
+
return ret;
3524
+
}
3525
+
EXPORT_SYMBOL_NS_GPL(iommu_replace_device_pasid, "IOMMUFD_INTERNAL");
3451
3526
3452
3527
/*
3453
3528
* iommu_detach_device_pasid() - Detach the domain from pasid of device