[v10,01/16] iommu: Move iommu fault data to linux/iommu.h

  The iommu fault data is currently defined in uapi/linux/iommu.h, but is
only used inside the iommu subsystem. Move it to linux/iommu.h, where it
will be more accessible to kernel drivers.

With this done, uapi/linux/iommu.h becomes empty and can be removed from
the tree.

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: Yi Liu <yi.l.liu@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Longfang Liu <liulongfang@huawei.com>
---
 include/linux/iommu.h      | 152 +++++++++++++++++++++++++++++++++-
 include/uapi/linux/iommu.h | 161 -------------------------------------
 MAINTAINERS                |   1 -
 3 files changed, 151 insertions(+), 163 deletions(-)
 delete mode 100644 include/uapi/linux/iommu.h
  

On Mon, Jan 22, 2024 at 01:42:53PM +0800, Lu Baolu wrote:
> The iommu fault data is currently defined in uapi/linux/iommu.h, but is
> only used inside the iommu subsystem. Move it to linux/iommu.h, where it
> will be more accessible to kernel drivers.
> 
> With this done, uapi/linux/iommu.h becomes empty and can be removed from
> the tree.

The reason for removing this [1] is that it is only being used by
internal code in the kernel. What happens with usespace code that have
used these definitions? Should we deprecate instead of just removing?

Best

[1] https://lore.kernel.org/all/20230711010642.19707-2-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: Yi Liu <yi.l.liu@intel.com>
> Tested-by: Yan Zhao <yan.y.zhao@intel.com>
> Tested-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  include/linux/iommu.h      | 152 +++++++++++++++++++++++++++++++++-
>  include/uapi/linux/iommu.h | 161 -------------------------------------
>  MAINTAINERS                |   1 -
>  3 files changed, 151 insertions(+), 163 deletions(-)
>  delete mode 100644 include/uapi/linux/iommu.h
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 1ea2a820e1eb..472a8ce029b1 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -14,7 +14,6 @@
>  #include <linux/err.h>
>  #include <linux/of.h>
>  #include <linux/iova_bitmap.h>
> -#include <uapi/linux/iommu.h>
>  
>  #define IOMMU_READ	(1 << 0)
>  #define IOMMU_WRITE	(1 << 1)
> @@ -44,6 +43,157 @@ struct iommu_sva;
>  struct iommu_fault_event;
>  struct iommu_dma_cookie;
>  
> +#define IOMMU_FAULT_PERM_READ	(1 << 0) /* read */
> +#define IOMMU_FAULT_PERM_WRITE	(1 << 1) /* write */
> +#define IOMMU_FAULT_PERM_EXEC	(1 << 2) /* exec */
> +#define IOMMU_FAULT_PERM_PRIV	(1 << 3) /* privileged */
> +
> +/* Generic fault types, can be expanded IRQ remapping fault */
> +enum iommu_fault_type {
> +	IOMMU_FAULT_DMA_UNRECOV = 1,	/* unrecoverable fault */
> +	IOMMU_FAULT_PAGE_REQ,		/* page request fault */
> +};
> +
> +enum iommu_fault_reason {
> +	IOMMU_FAULT_REASON_UNKNOWN = 0,
> +
> +	/* Could not access the PASID table (fetch caused external abort) */
> +	IOMMU_FAULT_REASON_PASID_FETCH,
> +
> +	/* PASID entry is invalid or has configuration errors */
> +	IOMMU_FAULT_REASON_BAD_PASID_ENTRY,
> +
> +	/*
> +	 * PASID is out of range (e.g. exceeds the maximum PASID
> +	 * supported by the IOMMU) or disabled.
> +	 */
> +	IOMMU_FAULT_REASON_PASID_INVALID,
> +
> +	/*
> +	 * An external abort occurred fetching (or updating) a translation
> +	 * table descriptor
> +	 */
> +	IOMMU_FAULT_REASON_WALK_EABT,
> +
> +	/*
> +	 * Could not access the page table entry (Bad address),
> +	 * actual translation fault
> +	 */
> +	IOMMU_FAULT_REASON_PTE_FETCH,
> +
> +	/* Protection flag check failed */
> +	IOMMU_FAULT_REASON_PERMISSION,
> +
> +	/* access flag check failed */
> +	IOMMU_FAULT_REASON_ACCESS,
> +
> +	/* Output address of a translation stage caused Address Size fault */
> +	IOMMU_FAULT_REASON_OOR_ADDRESS,
> +};
> +
> +/**
> + * struct iommu_fault_unrecoverable - Unrecoverable fault data
> + * @reason: reason of the fault, from &enum iommu_fault_reason
> + * @flags: parameters of this fault (IOMMU_FAULT_UNRECOV_* values)
> + * @pasid: Process Address Space ID
> + * @perm: requested permission access using by the incoming transaction
> + *        (IOMMU_FAULT_PERM_* values)
> + * @addr: offending page address
> + * @fetch_addr: address that caused a fetch abort, if any
> + */
> +struct iommu_fault_unrecoverable {
> +	__u32	reason;
> +#define IOMMU_FAULT_UNRECOV_PASID_VALID		(1 << 0)
> +#define IOMMU_FAULT_UNRECOV_ADDR_VALID		(1 << 1)
> +#define IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID	(1 << 2)
> +	__u32	flags;
> +	__u32	pasid;
> +	__u32	perm;
> +	__u64	addr;
> +	__u64	fetch_addr;
> +};
> +
> +/**
> + * struct iommu_fault_page_request - Page Request data
> + * @flags: encodes whether the corresponding fields are valid and whether this
> + *         is the last page in group (IOMMU_FAULT_PAGE_REQUEST_* values).
> + *         When IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID is set, the page response
> + *         must have the same PASID value as the page request. When it is clear,
> + *         the page response should not have a PASID.
> + * @pasid: Process Address Space ID
> + * @grpid: Page Request Group Index
> + * @perm: requested page permissions (IOMMU_FAULT_PERM_* values)
> + * @addr: page address
> + * @private_data: device-specific private information
> + */
> +struct iommu_fault_page_request {
> +#define IOMMU_FAULT_PAGE_REQUEST_PASID_VALID	(1 << 0)
> +#define IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE	(1 << 1)
> +#define IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA	(1 << 2)
> +#define IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID	(1 << 3)
> +	__u32	flags;
> +	__u32	pasid;
> +	__u32	grpid;
> +	__u32	perm;
> +	__u64	addr;
> +	__u64	private_data[2];
> +};
> +
> +/**
> + * struct iommu_fault - Generic fault data
> + * @type: fault type from &enum iommu_fault_type
> + * @padding: reserved for future use (should be zero)
> + * @event: fault event, when @type is %IOMMU_FAULT_DMA_UNRECOV
> + * @prm: Page Request message, when @type is %IOMMU_FAULT_PAGE_REQ
> + * @padding2: sets the fault size to allow for future extensions
> + */
> +struct iommu_fault {
> +	__u32	type;
> +	__u32	padding;
> +	union {
> +		struct iommu_fault_unrecoverable event;
> +		struct iommu_fault_page_request prm;
> +		__u8 padding2[56];
> +	};
> +};
> +
> +/**
> + * enum iommu_page_response_code - Return status of fault handlers
> + * @IOMMU_PAGE_RESP_SUCCESS: Fault has been handled and the page tables
> + *	populated, retry the access. This is "Success" in PCI PRI.
> + * @IOMMU_PAGE_RESP_FAILURE: General error. Drop all subsequent faults from
> + *	this device if possible. This is "Response Failure" in PCI PRI.
> + * @IOMMU_PAGE_RESP_INVALID: Could not handle this fault, don't retry the
> + *	access. This is "Invalid Request" in PCI PRI.
> + */
> +enum iommu_page_response_code {
> +	IOMMU_PAGE_RESP_SUCCESS = 0,
> +	IOMMU_PAGE_RESP_INVALID,
> +	IOMMU_PAGE_RESP_FAILURE,
> +};
> +
> +/**
> + * struct iommu_page_response - Generic page response information
> + * @argsz: User filled size of this data
> + * @version: API version of this structure
> + * @flags: encodes whether the corresponding fields are valid
> + *         (IOMMU_FAULT_PAGE_RESPONSE_* values)
> + * @pasid: Process Address Space ID
> + * @grpid: Page Request Group Index
> + * @code: response code from &enum iommu_page_response_code
> + */
> +struct iommu_page_response {
> +	__u32	argsz;
> +#define IOMMU_PAGE_RESP_VERSION_1	1
> +	__u32	version;
> +#define IOMMU_PAGE_RESP_PASID_VALID	(1 << 0)
> +	__u32	flags;
> +	__u32	pasid;
> +	__u32	grpid;
> +	__u32	code;
> +};
> +
> +
>  /* iommu fault flags */
>  #define IOMMU_FAULT_READ	0x0
>  #define IOMMU_FAULT_WRITE	0x1
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> deleted file mode 100644
> index 65d8b0234f69..000000000000
> --- a/include/uapi/linux/iommu.h
> +++ /dev/null
> @@ -1,161 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> -/*
> - * IOMMU user API definitions
> - */
> -
> -#ifndef _UAPI_IOMMU_H
> -#define _UAPI_IOMMU_H
> -
> -#include <linux/types.h>
> -
> -#define IOMMU_FAULT_PERM_READ	(1 << 0) /* read */
> -#define IOMMU_FAULT_PERM_WRITE	(1 << 1) /* write */
> -#define IOMMU_FAULT_PERM_EXEC	(1 << 2) /* exec */
> -#define IOMMU_FAULT_PERM_PRIV	(1 << 3) /* privileged */
> -
> -/* Generic fault types, can be expanded IRQ remapping fault */
> -enum iommu_fault_type {
> -	IOMMU_FAULT_DMA_UNRECOV = 1,	/* unrecoverable fault */
> -	IOMMU_FAULT_PAGE_REQ,		/* page request fault */
> -};
> -
> -enum iommu_fault_reason {
> -	IOMMU_FAULT_REASON_UNKNOWN = 0,
> -
> -	/* Could not access the PASID table (fetch caused external abort) */
> -	IOMMU_FAULT_REASON_PASID_FETCH,
> -
> -	/* PASID entry is invalid or has configuration errors */
> -	IOMMU_FAULT_REASON_BAD_PASID_ENTRY,
> -
> -	/*
> -	 * PASID is out of range (e.g. exceeds the maximum PASID
> -	 * supported by the IOMMU) or disabled.
> -	 */
> -	IOMMU_FAULT_REASON_PASID_INVALID,
> -
> -	/*
> -	 * An external abort occurred fetching (or updating) a translation
> -	 * table descriptor
> -	 */
> -	IOMMU_FAULT_REASON_WALK_EABT,
> -
> -	/*
> -	 * Could not access the page table entry (Bad address),
> -	 * actual translation fault
> -	 */
> -	IOMMU_FAULT_REASON_PTE_FETCH,
> -
> -	/* Protection flag check failed */
> -	IOMMU_FAULT_REASON_PERMISSION,
> -
> -	/* access flag check failed */
> -	IOMMU_FAULT_REASON_ACCESS,
> -
> -	/* Output address of a translation stage caused Address Size fault */
> -	IOMMU_FAULT_REASON_OOR_ADDRESS,
> -};
> -
> -/**
> - * struct iommu_fault_unrecoverable - Unrecoverable fault data
> - * @reason: reason of the fault, from &enum iommu_fault_reason
> - * @flags: parameters of this fault (IOMMU_FAULT_UNRECOV_* values)
> - * @pasid: Process Address Space ID
> - * @perm: requested permission access using by the incoming transaction
> - *        (IOMMU_FAULT_PERM_* values)
> - * @addr: offending page address
> - * @fetch_addr: address that caused a fetch abort, if any
> - */
> -struct iommu_fault_unrecoverable {
> -	__u32	reason;
> -#define IOMMU_FAULT_UNRECOV_PASID_VALID		(1 << 0)
> -#define IOMMU_FAULT_UNRECOV_ADDR_VALID		(1 << 1)
> -#define IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID	(1 << 2)
> -	__u32	flags;
> -	__u32	pasid;
> -	__u32	perm;
> -	__u64	addr;
> -	__u64	fetch_addr;
> -};
> -
> -/**
> - * struct iommu_fault_page_request - Page Request data
> - * @flags: encodes whether the corresponding fields are valid and whether this
> - *         is the last page in group (IOMMU_FAULT_PAGE_REQUEST_* values).
> - *         When IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID is set, the page response
> - *         must have the same PASID value as the page request. When it is clear,
> - *         the page response should not have a PASID.
> - * @pasid: Process Address Space ID
> - * @grpid: Page Request Group Index
> - * @perm: requested page permissions (IOMMU_FAULT_PERM_* values)
> - * @addr: page address
> - * @private_data: device-specific private information
> - */
> -struct iommu_fault_page_request {
> -#define IOMMU_FAULT_PAGE_REQUEST_PASID_VALID	(1 << 0)
> -#define IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE	(1 << 1)
> -#define IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA	(1 << 2)
> -#define IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID	(1 << 3)
> -	__u32	flags;
> -	__u32	pasid;
> -	__u32	grpid;
> -	__u32	perm;
> -	__u64	addr;
> -	__u64	private_data[2];
> -};
> -
> -/**
> - * struct iommu_fault - Generic fault data
> - * @type: fault type from &enum iommu_fault_type
> - * @padding: reserved for future use (should be zero)
> - * @event: fault event, when @type is %IOMMU_FAULT_DMA_UNRECOV
> - * @prm: Page Request message, when @type is %IOMMU_FAULT_PAGE_REQ
> - * @padding2: sets the fault size to allow for future extensions
> - */
> -struct iommu_fault {
> -	__u32	type;
> -	__u32	padding;
> -	union {
> -		struct iommu_fault_unrecoverable event;
> -		struct iommu_fault_page_request prm;
> -		__u8 padding2[56];
> -	};
> -};
> -
> -/**
> - * enum iommu_page_response_code - Return status of fault handlers
> - * @IOMMU_PAGE_RESP_SUCCESS: Fault has been handled and the page tables
> - *	populated, retry the access. This is "Success" in PCI PRI.
> - * @IOMMU_PAGE_RESP_FAILURE: General error. Drop all subsequent faults from
> - *	this device if possible. This is "Response Failure" in PCI PRI.
> - * @IOMMU_PAGE_RESP_INVALID: Could not handle this fault, don't retry the
> - *	access. This is "Invalid Request" in PCI PRI.
> - */
> -enum iommu_page_response_code {
> -	IOMMU_PAGE_RESP_SUCCESS = 0,
> -	IOMMU_PAGE_RESP_INVALID,
> -	IOMMU_PAGE_RESP_FAILURE,
> -};
> -
> -/**
> - * struct iommu_page_response - Generic page response information
> - * @argsz: User filled size of this data
> - * @version: API version of this structure
> - * @flags: encodes whether the corresponding fields are valid
> - *         (IOMMU_FAULT_PAGE_RESPONSE_* values)
> - * @pasid: Process Address Space ID
> - * @grpid: Page Request Group Index
> - * @code: response code from &enum iommu_page_response_code
> - */
> -struct iommu_page_response {
> -	__u32	argsz;
> -#define IOMMU_PAGE_RESP_VERSION_1	1
> -	__u32	version;
> -#define IOMMU_PAGE_RESP_PASID_VALID	(1 << 0)
> -	__u32	flags;
> -	__u32	pasid;
> -	__u32	grpid;
> -	__u32	code;
> -};
> -
> -#endif /* _UAPI_IOMMU_H */
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8d1052fa6a69..97846088d34d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11239,7 +11239,6 @@ F:	drivers/iommu/
>  F:	include/linux/iommu.h
>  F:	include/linux/iova.h
>  F:	include/linux/of_iommu.h
> -F:	include/uapi/linux/iommu.h
>  
>  IOMMUFD
>  M:	Jason Gunthorpe <jgg@nvidia.com>
> -- 
> 2.34.1
>
  

On 2024/1/25 17:17, Joel Granados wrote:
> On Mon, Jan 22, 2024 at 01:42:53PM +0800, Lu Baolu wrote:
>> The iommu fault data is currently defined in uapi/linux/iommu.h, but is
>> only used inside the iommu subsystem. Move it to linux/iommu.h, where it
>> will be more accessible to kernel drivers.
>>
>> With this done, uapi/linux/iommu.h becomes empty and can be removed from
>> the tree.
> The reason for removing this [1] is that it is only being used by
> internal code in the kernel. What happens with usespace code that have
> used these definitions? Should we deprecate instead of just removing?

The interfaces to deliver I/O page faults to user space have never been
implemented in the Linux kernel before. Therefore, from a uAPI point of
view, this definition is actually dead code.

Best regards,
baolu
  

On Thu, Jan 25, 2024 at 10:17:34AM +0100, Joel Granados wrote:
> On Mon, Jan 22, 2024 at 01:42:53PM +0800, Lu Baolu wrote:
> > The iommu fault data is currently defined in uapi/linux/iommu.h, but is
> > only used inside the iommu subsystem. Move it to linux/iommu.h, where it
> > will be more accessible to kernel drivers.
> > 
> > With this done, uapi/linux/iommu.h becomes empty and can be removed from
> > the tree.
> 
> The reason for removing this [1] is that it is only being used by
> internal code in the kernel. What happens with usespace code that have
> used these definitions? Should we deprecate instead of just removing?

There was never an in-tree kernel implementation. Any userspace that
implemented this needs to decide on its own if it will continue to
support the non-mainline kernel and provide a copy of the definitions
itself..

(it was a process mistake to merge a uapi header without a
corresponding uapi implementation, sorry)

Jason
  

On Thu, Jan 25, 2024 at 09:43:37AM -0400, Jason Gunthorpe wrote:
> On Thu, Jan 25, 2024 at 10:17:34AM +0100, Joel Granados wrote:
> > On Mon, Jan 22, 2024 at 01:42:53PM +0800, Lu Baolu wrote:
> > > The iommu fault data is currently defined in uapi/linux/iommu.h, but is
> > > only used inside the iommu subsystem. Move it to linux/iommu.h, where it
> > > will be more accessible to kernel drivers.
> > > 
> > > With this done, uapi/linux/iommu.h becomes empty and can be removed from
> > > the tree.
> > 
> > The reason for removing this [1] is that it is only being used by
> > internal code in the kernel. What happens with usespace code that have
> > used these definitions? Should we deprecate instead of just removing?
> 
> There was never an in-tree kernel implementation. Any userspace that
> implemented this needs to decide on its own if it will continue to
> support the non-mainline kernel and provide a copy of the definitions
> itself..
> 
> (it was a process mistake to merge a uapi header without a
> corresponding uapi implementation, sorry)
Thx.
This makes sense and its actually a good thing that we remove it.

Best
> 
> Jason
  

On Thu, Jan 25, 2024 at 07:21:53PM +0800, Baolu Lu wrote:
> On 2024/1/25 17:17, Joel Granados wrote:
> > On Mon, Jan 22, 2024 at 01:42:53PM +0800, Lu Baolu wrote:
> >> The iommu fault data is currently defined in uapi/linux/iommu.h, but is
> >> only used inside the iommu subsystem. Move it to linux/iommu.h, where it
> >> will be more accessible to kernel drivers.
> >>
> >> With this done, uapi/linux/iommu.h becomes empty and can be removed from
> >> the tree.
> > The reason for removing this [1] is that it is only being used by
> > internal code in the kernel. What happens with usespace code that have
> > used these definitions? Should we deprecate instead of just removing?
> 
> The interfaces to deliver I/O page faults to user space have never been
> implemented in the Linux kernel before. Therefore, from a uAPI point of
> view, this definition is actually dead code.
thx for the explanation.
I was thinking it was something like that. Just wanted to make sure.

Best