by Joel Granados

[permalink] [raw]

Subject: Re: [PATCH v10 01/16] iommu: Move iommu fault data to 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/[email protected]/
>
> Signed-off-by: Lu Baolu <[email protected]>
> Reviewed-by: Jason Gunthorpe <[email protected]>
> Reviewed-by: Kevin Tian <[email protected]>
> Reviewed-by: Yi Liu <[email protected]>
> Tested-by: Yan Zhao <[email protected]>
> Tested-by: Longfang Liu <[email protected]>
> ---
> 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 <[email protected]>
> --
> 2.34.1
>

--

Joel Granados

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2024-01-25 10:23:51

On Mon, Jan 22, 2024 at 01:43:07PM +0800, Lu Baolu wrote:
> The iopf_group_response() should return void, as nothing can do anything
> with the failure. This implies that ops->page_response() must also return
> void; this is consistent with what the drivers do. The failure paths,
> which are all integrity validations of the fault, should be WARN_ON'd,
> not return codes.
>
> If the iommu core fails to enqueue the fault, it should respond the fault
> directly by calling ops->page_response() instead of returning an error
> number and relying on the iommu drivers to do so. Consolidate the error
> fault handling code in the core.
>
> Co-developed-by: Jason Gunthorpe <[email protected]>
> Signed-off-by: Jason Gunthorpe <[email protected]>
> Signed-off-by: Lu Baolu <[email protected]>
> ---
> include/linux/iommu.h | 14 +--
> drivers/iommu/intel/iommu.h | 4 +-
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 50 +++-----
> drivers/iommu/intel/svm.c | 18 +--
> drivers/iommu/io-pgfault.c | 132 +++++++++++---------
> 5 files changed, 99 insertions(+), 119 deletions(-)
>
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 48196efc9327..d7b6f4017254 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -578,9 +578,8 @@ struct iommu_ops {
> int (*dev_enable_feat)(struct device *dev, enum iommu_dev_features f);
> int (*dev_disable_feat)(struct device *dev, enum iommu_dev_features f);
>
> - int (*page_response)(struct device *dev,
> - struct iopf_fault *evt,
> - struct iommu_page_response *msg);
> + void (*page_response)(struct device *dev, struct iopf_fault *evt,
> + struct iommu_page_response *msg);
>
> int (*def_domain_type)(struct device *dev);
> void (*remove_dev_pasid)(struct device *dev, ioasid_t pasid);
> @@ -1551,8 +1550,8 @@ void iopf_queue_free(struct iopf_queue *queue);
> int iopf_queue_discard_partial(struct iopf_queue *queue);
> void iopf_free_group(struct iopf_group *group);
> int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt);
> -int iopf_group_response(struct iopf_group *group,
> - enum iommu_page_response_code status);
> +void iopf_group_response(struct iopf_group *group,
> + enum iommu_page_response_code status);
> #else
> static inline int
> iopf_queue_add_device(struct iopf_queue *queue, struct device *dev)
> @@ -1594,10 +1593,9 @@ iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
> return -ENODEV;
> }
>
> -static inline int iopf_group_response(struct iopf_group *group,
> - enum iommu_page_response_code status)
> +static inline void iopf_group_response(struct iopf_group *group,
> + enum iommu_page_response_code status)
> {
> - return -ENODEV;
> }
> #endif /* CONFIG_IOMMU_IOPF */
> #endif /* __LINUX_IOMMU_H */
> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index 696d95293a69..cf9a28c7fab8 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -1079,8 +1079,8 @@ struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *parent,
> void intel_svm_check(struct intel_iommu *iommu);
> int intel_svm_enable_prq(struct intel_iommu *iommu);
> int intel_svm_finish_prq(struct intel_iommu *iommu);
> -int intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
> - struct iommu_page_response *msg);
> +void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
> + struct iommu_page_response *msg);
> struct iommu_domain *intel_svm_domain_alloc(void);
> void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid);
> void intel_drain_pasid_prq(struct device *dev, u32 pasid);
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 4e93e845458c..42eb59cb99f4 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -920,31 +920,29 @@ static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
> return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, true);
> }
>
> -static int arm_smmu_page_response(struct device *dev,
> - struct iopf_fault *unused,
> - struct iommu_page_response *resp)
> +static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused,
> + struct iommu_page_response *resp)
> {
> struct arm_smmu_cmdq_ent cmd = {0};
> struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> int sid = master->streams[0].id;
>
> - if (master->stall_enabled) {
> - cmd.opcode = CMDQ_OP_RESUME;
> - cmd.resume.sid = sid;
> - cmd.resume.stag = resp->grpid;
> - switch (resp->code) {
> - case IOMMU_PAGE_RESP_INVALID:
> - case IOMMU_PAGE_RESP_FAILURE:
> - cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
> - break;
> - case IOMMU_PAGE_RESP_SUCCESS:
> - cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
> - break;
> - default:
> - return -EINVAL;
> - }
> - } else {
> - return -ENODEV;
> + if (WARN_ON(!master->stall_enabled))
> + return;
> +
> + cmd.opcode = CMDQ_OP_RESUME;
> + cmd.resume.sid = sid;
> + cmd.resume.stag = resp->grpid;
> + switch (resp->code) {
> + case IOMMU_PAGE_RESP_INVALID:
> + case IOMMU_PAGE_RESP_FAILURE:
> + cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
> + break;
> + case IOMMU_PAGE_RESP_SUCCESS:
> + cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
> + break;
> + default:
> + break;
> }
>
> arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
> @@ -954,8 +952,6 @@ static int arm_smmu_page_response(struct device *dev,
> * terminated... at some point in the future. PRI_RESP is fire and
> * forget.
> */
> -
> - return 0;
> }
>
> /* Context descriptor manipulation functions */
> @@ -1516,16 +1512,6 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
> }
>
> ret = iommu_report_device_fault(master->dev, &fault_evt);
> - if (ret && flt->type == IOMMU_FAULT_PAGE_REQ) {
> - /* Nobody cared, abort the access */
> - struct iommu_page_response resp = {
> - .pasid = flt->prm.pasid,
> - .grpid = flt->prm.grpid,
> - .code = IOMMU_PAGE_RESP_FAILURE,
> - };
> - arm_smmu_page_response(master->dev, &fault_evt, &resp);
> - }
> -
> out_unlock:
> mutex_unlock(&smmu->streams_mutex);
> return ret;
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index e1cbcb9515f0..2f8716636dbb 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -740,9 +740,8 @@ static irqreturn_t prq_event_thread(int irq, void *d)
> return IRQ_RETVAL(handled);
> }
>
> -int intel_svm_page_response(struct device *dev,
> - struct iopf_fault *evt,
> - struct iommu_page_response *msg)
> +void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
> + struct iommu_page_response *msg)
> {
> struct device_domain_info *info = dev_iommu_priv_get(dev);
> struct intel_iommu *iommu = info->iommu;
> @@ -751,7 +750,6 @@ int intel_svm_page_response(struct device *dev,
> bool private_present;
> bool pasid_present;
> bool last_page;
> - int ret = 0;
> u16 sid;
>
> prm = &evt->fault.prm;
> @@ -760,16 +758,6 @@ int intel_svm_page_response(struct device *dev,
> private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
> last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
>
> - if (!pasid_present) {
> - ret = -EINVAL;
> - goto out;
> - }
> -
> - if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
> - ret = -EINVAL;
> - goto out;
> - }
> -
> /*
> * Per VT-d spec. v3.0 ch7.7, system software must respond
> * with page group response if private data is present (PDP)
> @@ -798,8 +786,6 @@ int intel_svm_page_response(struct device *dev,
>
> qi_submit_sync(iommu, &desc, 1, 0);
> }
> -out:
> - return ret;
> }
>
> static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
> index c22e13df84c2..6e63e5a02884 100644
> --- a/drivers/iommu/io-pgfault.c
> +++ b/drivers/iommu/io-pgfault.c
> @@ -39,7 +39,7 @@ static void iopf_put_dev_fault_param(struct iommu_fault_param *fault_param)
> kfree_rcu(fault_param, rcu);
> }
>
> -void iopf_free_group(struct iopf_group *group)
> +static void __iopf_free_group(struct iopf_group *group)
> {
> struct iopf_fault *iopf, *next;
>
> @@ -50,6 +50,11 @@ void iopf_free_group(struct iopf_group *group)
>
> /* Pair with iommu_report_device_fault(). */
> iopf_put_dev_fault_param(group->fault_param);
> +}
> +
> +void iopf_free_group(struct iopf_group *group)
> +{
> + __iopf_free_group(group);
> kfree(group);
> }
> EXPORT_SYMBOL_GPL(iopf_free_group);
> @@ -97,14 +102,49 @@ static int report_partial_fault(struct iommu_fault_param *fault_param,
> return 0;
> }
>
> +static struct iopf_group *iopf_group_alloc(struct iommu_fault_param *iopf_param,
> + struct iopf_fault *evt,
> + struct iopf_group *abort_group)
> +{
> + struct iopf_fault *iopf, *next;
> + struct iopf_group *group;
> +
> + group = kzalloc(sizeof(*group), GFP_KERNEL);
> + if (!group) {
> + /*
> + * We always need to construct the group as we need it to abort
> + * the request at the driver if it cfan't be handled.
> + */
> + group = abort_group;
> + }
> +
> + group->fault_param = iopf_param;
> + group->last_fault.fault = evt->fault;
> + INIT_LIST_HEAD(&group->faults);
> + INIT_LIST_HEAD(&group->pending_node);
> + list_add(&group->last_fault.list, &group->faults);
> +
> + /* See if we have partial faults for this group */
> + mutex_lock(&iopf_param->lock);
> + list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
> + if (iopf->fault.prm.grpid == evt->fault.prm.grpid)
> + /* Insert *before* the last fault */
> + list_move(&iopf->list, &group->faults);
> + }
> + list_add(&group->pending_node, &iopf_param->faults);
> + mutex_unlock(&iopf_param->lock);
> +
> + return group;
> +}
> +
> /**
> * iommu_report_device_fault() - Report fault event to device driver
> * @dev: the device
> * @evt: fault event data
> *
> * Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ
> - * handler. When this function fails and the fault is recoverable, it is the
> - * caller's responsibility to complete the fault.
> + * handler. If this function fails then ops->page_response() was called to
> + * complete evt if required.
> *
> * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard
> * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't
> @@ -143,22 +183,18 @@ int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
> {
> struct iommu_fault *fault = &evt->fault;
> struct iommu_fault_param *iopf_param;
> - struct iopf_fault *iopf, *next;
> - struct iommu_domain *domain;
> + struct iopf_group abort_group = {};
> struct iopf_group *group;
> int ret;
>
> - if (fault->type != IOMMU_FAULT_PAGE_REQ)
> - return -EOPNOTSUPP;
> -
> iopf_param = iopf_get_dev_fault_param(dev);
> - if (!iopf_param)
> + if (WARN_ON(!iopf_param))
> return -ENODEV;
>
> if (!(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) {
> ret = report_partial_fault(iopf_param, fault);
> iopf_put_dev_fault_param(iopf_param);
> -
> + /* A request that is not the last does not need to be ack'd */
> return ret;
> }
>
> @@ -170,56 +206,33 @@ int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
> * will send a response to the hardware. We need to clean up before
> * leaving, otherwise partial faults will be stuck.
> */
> - domain = get_domain_for_iopf(dev, fault);
> - if (!domain) {
> + group = iopf_group_alloc(iopf_param, evt, &abort_group);
> + if (group == &abort_group) {
> + ret = -ENOMEM;
> + goto err_abort;
> + }
> +
> + group->domain = get_domain_for_iopf(dev, fault);
> + if (!group->domain) {
> ret = -EINVAL;
> - goto cleanup_partial;
> + goto err_abort;
> }
>
> - group = kzalloc(sizeof(*group), GFP_KERNEL);
> - if (!group) {
> - ret = -ENOMEM;
> - goto cleanup_partial;
> - }
> -
> - group->fault_param = iopf_param;
> - group->last_fault.fault = *fault;
> - INIT_LIST_HEAD(&group->faults);
> - INIT_LIST_HEAD(&group->pending_node);
> - group->domain = domain;
> - list_add(&group->last_fault.list, &group->faults);
> -
> - /* See if we have partial faults for this group */
> - mutex_lock(&iopf_param->lock);
> - list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
> - if (iopf->fault.prm.grpid == fault->prm.grpid)
> - /* Insert *before* the last fault */
> - list_move(&iopf->list, &group->faults);
> - }
> - list_add(&group->pending_node, &iopf_param->faults);
> - mutex_unlock(&iopf_param->lock);
> + /*
> + * On success iopf_handler must call iopf_group_response() and
> + * iopf_free_group()
> + */
> + ret = group->domain->iopf_handler(group);
> + if (ret)
> + goto err_abort;
> + return 0;
>
> - ret = domain->iopf_handler(group);
> - if (ret) {
> - mutex_lock(&iopf_param->lock);
> - list_del_init(&group->pending_node);
> - mutex_unlock(&iopf_param->lock);
> +err_abort:
> + iopf_group_response(group, IOMMU_PAGE_RESP_FAILURE);
> + if (group == &abort_group)
> + __iopf_free_group(group);
> + else
> iopf_free_group(group);
> - }
> -
> - return ret;
> -
> -cleanup_partial:
> - mutex_lock(&iopf_param->lock);
> - list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
> - if (iopf->fault.prm.grpid == fault->prm.grpid) {
> - list_del(&iopf->list);
> - kfree(iopf);
> - }
> - }
> - mutex_unlock(&iopf_param->lock);
> - iopf_put_dev_fault_param(iopf_param);
> -
> return ret;
> }
> EXPORT_SYMBOL_GPL(iommu_report_device_fault);
> @@ -262,8 +275,8 @@ EXPORT_SYMBOL_GPL(iopf_queue_flush_dev);
> *
> * Return 0 on success and <0 on error.
> */
Should you adjust the docs as well?

> -int iopf_group_response(struct iopf_group *group,
> - enum iommu_page_response_code status)
> +void iopf_group_response(struct iopf_group *group,
> + enum iommu_page_response_code status)
> {
> struct iommu_fault_param *fault_param = group->fault_param;
> struct iopf_fault *iopf = &group->last_fault;
> @@ -274,7 +287,6 @@ int iopf_group_response(struct iopf_group *group,
> .grpid = iopf->fault.prm.grpid,
> .code = status,
> };
> - int ret = -EINVAL;
>
> if ((iopf->fault.prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) &&
> (iopf->fault.prm.flags & IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID))
> @@ -283,12 +295,10 @@ int iopf_group_response(struct iopf_group *group,
> /* Only send response if there is a fault report pending */
> mutex_lock(&fault_param->lock);
> if (!list_empty(&group->pending_node)) {
> - ret = ops->page_response(dev, &group->last_fault, &resp);
> + ops->page_response(dev, &group->last_fault, &resp);
> list_del_init(&group->pending_node);
> }
> mutex_unlock(&fault_param->lock);
> -
> - return ret;
> }
> EXPORT_SYMBOL_GPL(iopf_group_response);
>
> --
> 2.34.1
>

--

Joel Granados

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2024-01-25 16:32:59

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

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Joel Granados

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2024-01-26 14:44:51

by Joel Granados

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Subject: Re: [PATCH v10 01/16] iommu: Move iommu fault data to linux/iommu.h

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

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Joel Granados

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2024-02-02 15:37:01

by Jason Gunthorpe

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Subject: Re: [PATCH v10 15/16] iommu: Make iopf_group_response() return void

2024-02-02 15:39:49

by Jason Gunthorpe

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