linux/drivers/iommu/iommu-sva.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Helpers for IOMMU drivers implementing SVA
*/
#include <linux/mmu_context.h>
#include <linux/mutex.h>
#include <linux/sched/mm.h>
#include <linux/iommu.h>
#include "iommu-priv.h"
static DEFINE_MUTEX(iommu_sva_lock);
static struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
struct mm_struct *mm);
/* Allocate a PASID for the mm within range (inclusive) */
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct device *dev)
{
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
struct iommu_mm_data *iommu_mm;
ioasid_t pasid;
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
lockdep_assert_held(&iommu_sva_lock);
if (!arch_pgtable_dma_compat(mm))
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
return ERR_PTR(-EBUSY);
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iommu_mm = mm->iommu_mm;
/* Is a PASID already associated with this mm? */
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
if (iommu_mm) {
if (iommu_mm->pasid >= dev->iommu->max_pasids)
return ERR_PTR(-EOVERFLOW);
return iommu_mm;
}
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iommu_mm = kzalloc(sizeof(struct iommu_mm_data), GFP_KERNEL);
if (!iommu_mm)
return ERR_PTR(-ENOMEM);
pasid = iommu_alloc_global_pasid(dev);
if (pasid == IOMMU_PASID_INVALID) {
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
kfree(iommu_mm);
return ERR_PTR(-ENOSPC);
}
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iommu_mm->pasid = pasid;
INIT_LIST_HEAD(&iommu_mm->sva_domains);
/*
* Make sure the write to mm->iommu_mm is not reordered in front of
* initialization to iommu_mm fields. If it does, readers may see a
* valid iommu_mm with uninitialized values.
*/
smp_store_release(&mm->iommu_mm, iommu_mm);
return iommu_mm;
}
/**
* iommu_sva_bind_device() - Bind a process address space to a device
* @dev: the device
* @mm: the mm to bind, caller must hold a reference to mm_users
*
* Create a bond between device and address space, allowing the device to
* access the mm using the PASID returned by iommu_sva_get_pasid(). If a
* bond already exists between @device and @mm, an additional internal
* reference is taken. Caller must call iommu_sva_unbind_device()
* to release each reference.
*
* iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
* initialize the required SVA features.
*
* On error, returns an ERR_PTR value.
*/
struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
{
struct iommu_group *group = dev->iommu_group;
struct iommu_attach_handle *attach_handle;
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
struct iommu_mm_data *iommu_mm;
struct iommu_domain *domain;
struct iommu_sva *handle;
int ret;
if (!group)
return ERR_PTR(-ENODEV);
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
mutex_lock(&iommu_sva_lock);
/* Allocate mm->pasid if necessary. */
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iommu_mm = iommu_alloc_mm_data(mm, dev);
if (IS_ERR(iommu_mm)) {
ret = PTR_ERR(iommu_mm);
goto out_unlock;
}
/* A bond already exists, just take a reference`. */
attach_handle = iommu_attach_handle_get(group, iommu_mm->pasid, IOMMU_DOMAIN_SVA);
if (!IS_ERR(attach_handle)) {
handle = container_of(attach_handle, struct iommu_sva, handle);
if (attach_handle->domain->mm != mm) {
ret = -EBUSY;
goto out_unlock;
iommu/sva: Restore SVA handle sharing Prior to commit 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") the code allowed a SVA handle to be bound multiple times to the same (mm, device) pair. This was alluded to in the kdoc comment, but we had understood this to be more a remark about allowing multiple devices, not a literal same-driver re-opening the same SVA. It turns out uacce and idxd were both relying on the core code to handle reference counting for same-device same-mm scenarios. As this looks hard to resolve in the drivers bring it back to the core code. The new design has changed the meaning of the domain->users refcount to refer to the number of devices that are sharing that domain for the same mm. This is part of the design to lift the SVA domain de-duplication out of the drivers. Return the old behavior by explicitly de-duplicating the struct iommu_sva handle. The same (mm, device) will return the same handle pointer and the core code will handle tracking this. The last unbind of the handle will destroy it. Fixes: 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") Reported-by: Zhangfei Gao <zhangfei.gao@linaro.org> Closes: https://lore.kernel.org/all/20240221110658.529-1-zhangfei.gao@linaro.org/ Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/0-v1-9455fc497a6f+3b4-iommu_sva_sharing_jgg@nvidia.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2024-02-22 14:07:41 +00:00
}
refcount_inc(&handle->users);
mutex_unlock(&iommu_sva_lock);
return handle;
}
if (PTR_ERR(attach_handle) != -ENOENT) {
ret = PTR_ERR(attach_handle);
goto out_unlock;
iommu/sva: Restore SVA handle sharing Prior to commit 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") the code allowed a SVA handle to be bound multiple times to the same (mm, device) pair. This was alluded to in the kdoc comment, but we had understood this to be more a remark about allowing multiple devices, not a literal same-driver re-opening the same SVA. It turns out uacce and idxd were both relying on the core code to handle reference counting for same-device same-mm scenarios. As this looks hard to resolve in the drivers bring it back to the core code. The new design has changed the meaning of the domain->users refcount to refer to the number of devices that are sharing that domain for the same mm. This is part of the design to lift the SVA domain de-duplication out of the drivers. Return the old behavior by explicitly de-duplicating the struct iommu_sva handle. The same (mm, device) will return the same handle pointer and the core code will handle tracking this. The last unbind of the handle will destroy it. Fixes: 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") Reported-by: Zhangfei Gao <zhangfei.gao@linaro.org> Closes: https://lore.kernel.org/all/20240221110658.529-1-zhangfei.gao@linaro.org/ Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/0-v1-9455fc497a6f+3b4-iommu_sva_sharing_jgg@nvidia.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2024-02-22 14:07:41 +00:00
}
handle = kzalloc(sizeof(*handle), GFP_KERNEL);
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
if (!handle) {
ret = -ENOMEM;
goto out_unlock;
}
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
/* Search for an existing domain. */
list_for_each_entry(domain, &mm->iommu_mm->sva_domains, next) {
ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid,
&handle->handle);
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
if (!ret) {
domain->users++;
goto out;
}
}
/* Allocate a new domain and set it on device pasid. */
domain = iommu_sva_domain_alloc(dev, mm);
if (IS_ERR(domain)) {
ret = PTR_ERR(domain);
goto out_free_handle;
}
ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid,
&handle->handle);
if (ret)
goto out_free_domain;
domain->users = 1;
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
list_add(&domain->next, &mm->iommu_mm->sva_domains);
out:
refcount_set(&handle->users, 1);
mutex_unlock(&iommu_sva_lock);
handle->dev = dev;
return handle;
out_free_domain:
iommu_domain_free(domain);
out_free_handle:
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
kfree(handle);
out_unlock:
mutex_unlock(&iommu_sva_lock);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
/**
* iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device
* @handle: the handle returned by iommu_sva_bind_device()
*
* Put reference to a bond between device and address space. The device should
* not be issuing any more transaction for this PASID. All outstanding page
* requests for this PASID must have been flushed to the IOMMU.
*/
void iommu_sva_unbind_device(struct iommu_sva *handle)
{
struct iommu_domain *domain = handle->handle.domain;
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
struct iommu_mm_data *iommu_mm = domain->mm->iommu_mm;
struct device *dev = handle->dev;
mutex_lock(&iommu_sva_lock);
iommu/sva: Restore SVA handle sharing Prior to commit 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") the code allowed a SVA handle to be bound multiple times to the same (mm, device) pair. This was alluded to in the kdoc comment, but we had understood this to be more a remark about allowing multiple devices, not a literal same-driver re-opening the same SVA. It turns out uacce and idxd were both relying on the core code to handle reference counting for same-device same-mm scenarios. As this looks hard to resolve in the drivers bring it back to the core code. The new design has changed the meaning of the domain->users refcount to refer to the number of devices that are sharing that domain for the same mm. This is part of the design to lift the SVA domain de-duplication out of the drivers. Return the old behavior by explicitly de-duplicating the struct iommu_sva handle. The same (mm, device) will return the same handle pointer and the core code will handle tracking this. The last unbind of the handle will destroy it. Fixes: 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains") Reported-by: Zhangfei Gao <zhangfei.gao@linaro.org> Closes: https://lore.kernel.org/all/20240221110658.529-1-zhangfei.gao@linaro.org/ Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/0-v1-9455fc497a6f+3b4-iommu_sva_sharing_jgg@nvidia.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2024-02-22 14:07:41 +00:00
if (!refcount_dec_and_test(&handle->users)) {
mutex_unlock(&iommu_sva_lock);
return;
}
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);
if (--domain->users == 0) {
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
list_del(&domain->next);
iommu_domain_free(domain);
}
mutex_unlock(&iommu_sva_lock);
kfree(handle);
}
EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
u32 iommu_sva_get_pasid(struct iommu_sva *handle)
{
struct iommu_domain *domain = handle->handle.domain;
return mm_get_enqcmd_pasid(domain->mm);
}
EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
void mm_pasid_drop(struct mm_struct *mm)
{
struct iommu_mm_data *iommu_mm = mm->iommu_mm;
if (!iommu_mm)
return;
iommu_free_global_pasid(iommu_mm->pasid);
kfree(iommu_mm);
}
/*
* I/O page fault handler for SVA
*/
static enum iommu_page_response_code
iommu_sva_handle_mm(struct iommu_fault *fault, struct mm_struct *mm)
{
vm_fault_t ret;
struct vm_area_struct *vma;
unsigned int access_flags = 0;
unsigned int fault_flags = FAULT_FLAG_REMOTE;
struct iommu_fault_page_request *prm = &fault->prm;
enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
return status;
if (!mmget_not_zero(mm))
return status;
mmap_read_lock(mm);
vma = vma_lookup(mm, prm->addr);
if (!vma)
/* Unmapped area */
goto out_put_mm;
if (prm->perm & IOMMU_FAULT_PERM_READ)
access_flags |= VM_READ;
if (prm->perm & IOMMU_FAULT_PERM_WRITE) {
access_flags |= VM_WRITE;
fault_flags |= FAULT_FLAG_WRITE;
}
if (prm->perm & IOMMU_FAULT_PERM_EXEC) {
access_flags |= VM_EXEC;
fault_flags |= FAULT_FLAG_INSTRUCTION;
}
if (!(prm->perm & IOMMU_FAULT_PERM_PRIV))
fault_flags |= FAULT_FLAG_USER;
if (access_flags & ~vma->vm_flags)
/* Access fault */
goto out_put_mm;
ret = handle_mm_fault(vma, prm->addr, fault_flags, NULL);
status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID :
IOMMU_PAGE_RESP_SUCCESS;
out_put_mm:
mmap_read_unlock(mm);
mmput(mm);
return status;
}
static void iommu_sva_handle_iopf(struct work_struct *work)
{
struct iopf_fault *iopf;
struct iopf_group *group;
enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS;
group = container_of(work, struct iopf_group, work);
list_for_each_entry(iopf, &group->faults, list) {
/*
* For the moment, errors are sticky: don't handle subsequent
* faults in the group if there is an error.
*/
if (status != IOMMU_PAGE_RESP_SUCCESS)
break;
status = iommu_sva_handle_mm(&iopf->fault,
group->attach_handle->domain->mm);
}
iommu: Support mm PASID 1:n with sva domains Each mm bound to devices gets a PASID and corresponding sva domains allocated in iommu_sva_bind_device(), which are referenced by iommu_mm field of the mm. The PASID is released in __mmdrop(), while a sva domain is released when no one is using it (the reference count is decremented in iommu_sva_unbind_device()). However, although sva domains and their PASID are separate objects such that their own life cycles could be handled independently, an enqcmd use case may require releasing the PASID in releasing the mm (i.e., once a PASID is allocated for a mm, it will be permanently used by the mm and won't be released until the end of mm) and only allows to drop the PASID after the sva domains are released. To this end, mmgrab() is called in iommu_sva_domain_alloc() to increment the mm reference count and mmdrop() is invoked in iommu_domain_free() to decrement the mm reference count. Since the required info of PASID and sva domains is kept in struct iommu_mm_data of a mm, use mm->iommu_mm field instead of the old pasid field in mm struct. The sva domain list is protected by iommu_sva_lock. Besides, this patch removes mm_pasid_init(), as with the introduced iommu_mm structure, initializing mm pasid in mm_init() is unnecessary. Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Signed-off-by: Tina Zhang <tina.zhang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20231027000525.1278806-6-tina.zhang@intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-10-27 00:05:24 +00:00
iopf_group_response(group, status);
iopf_free_group(group);
}
static int iommu_sva_iopf_handler(struct iopf_group *group)
{
iommu: Use refcount for fault data access The per-device fault data structure stores information about faults occurring on a device. Its lifetime spans from IOPF enablement to disablement. Multiple paths, including IOPF reporting, handling, and responding, may access it concurrently. Previously, a mutex protected the fault data from use after free. But this is not performance friendly due to the critical nature of IOPF handling paths. Refine this with a refcount-based approach. The fault data pointer is obtained within an RCU read region with a refcount. The fault data pointer is returned for usage only when the pointer is valid and a refcount is successfully obtained. The fault data is freed with kfree_rcu(), ensuring data is only freed after all RCU critical regions complete. An iopf handling work starts once an iopf group is created. The handling work continues until iommu_page_response() is called to respond to the iopf and the iopf group is freed. During this time, the device fault parameter should always be available. Add a pointer to the device fault parameter in the iopf_group structure and hold the reference until the iopf_group is freed. Make iommu_page_response() static as it is only used in io-pgfault.c. Co-developed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.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> Tested-by: Yan Zhao <yan.y.zhao@intel.com> Link: https://lore.kernel.org/r/20240212012227.119381-13-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2024-02-12 01:22:23 +00:00
struct iommu_fault_param *fault_param = group->fault_param;
INIT_WORK(&group->work, iommu_sva_handle_iopf);
if (!queue_work(fault_param->queue->wq, &group->work))
return -EBUSY;
return 0;
}
static struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
struct mm_struct *mm)
{
const struct iommu_ops *ops = dev_iommu_ops(dev);
struct iommu_domain *domain;
if (ops->domain_alloc_sva) {
domain = ops->domain_alloc_sva(dev, mm);
if (IS_ERR(domain))
return domain;
} else {
domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
if (!domain)
return ERR_PTR(-ENOMEM);
}
domain->type = IOMMU_DOMAIN_SVA;
mmgrab(mm);
domain->mm = mm;
domain->owner = ops;
domain->iopf_handler = iommu_sva_iopf_handler;
return domain;
}