From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auger Eric Subject: Re: [PATCH v4 02/22] iommu: introduce device fault data Date: Wed, 6 Mar 2019 10:38:25 +0100 Message-ID: <43c5c3be-a609-62e1-efaa-c5571bb762c6@redhat.com> References: <20190218135504.25048-1-eric.auger@redhat.com> <20190218135504.25048-3-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jean-Philippe Brucker , eric.auger.pro@gmail.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, joro@8bytes.org, alex.williamson@redhat.com, jacob.jun.pan@linux.intel.com, yi.l.liu@linux.intel.com, will.deacon@arm.com, robin.murphy@arm.com Cc: marc.zyngier@arm.com, peter.maydell@linaro.org, kevin.tian@intel.com, ashok.raj@intel.com, christoffer.dall@arm.com List-Id: iommu@lists.linux-foundation.org Hi Jean, On 3/5/19 3:56 PM, Jean-Philippe Brucker wrote: > On 18/02/2019 13:54, Eric Auger wrote: >> From: Jacob Pan >> >> Device faults detected by IOMMU can be reported outside the IOMMU >> subsystem for further processing. This patch introduces >> a generic device fault data structure. >> >> The fault can be either an unrecoverable fault or a page request, >> also referred to as a recoverable fault. >> >> We only care about non internal faults that are likely to be reported >> to an external subsystem. >> >> Signed-off-by: Jacob Pan >> Signed-off-by: Jean-Philippe Brucker >> Signed-off-by: Liu, Yi L >> Signed-off-by: Ashok Raj >> Signed-off-by: Eric Auger >> >> --- >> >> v3 -> v4: >> - use a union containing aither an unrecoverable fault or a page >> request message. Move the device private data in the page request >> structure. Reshuffle the fields and use flags. >> - move fault perm attributes to the uapi >> - remove a bunch of iommu_fault_reason enum values that were related >> to internal errors >> --- >> include/linux/iommu.h | 47 +++++++++++++++ >> include/uapi/linux/iommu.h | 115 +++++++++++++++++++++++++++++++++++++ >> 2 files changed, 162 insertions(+) >> create mode 100644 include/uapi/linux/iommu.h >> >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index e90da6b6f3d1..032d33894723 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -25,6 +25,7 @@ >> #include >> #include >> #include >> +#include >> >> #define IOMMU_READ (1 << 0) >> #define IOMMU_WRITE (1 << 1) >> @@ -48,6 +49,7 @@ struct bus_type; >> struct device; >> struct iommu_domain; >> struct notifier_block; >> +struct iommu_fault_event; >> >> /* iommu fault flags */ >> #define IOMMU_FAULT_READ 0x0 >> @@ -55,6 +57,7 @@ struct notifier_block; >> >> typedef int (*iommu_fault_handler_t)(struct iommu_domain *, >> struct device *, unsigned long, int, void *); >> +typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *, void *); >> >> struct iommu_domain_geometry { >> dma_addr_t aperture_start; /* First address that can be mapped */ >> @@ -243,6 +246,49 @@ struct iommu_device { >> struct device *dev; >> }; >> >> +/** >> + * struct iommu_fault_event - Generic per device fault data >> + * >> + * - PCI and non-PCI devices >> + * - Recoverable faults (e.g. page request), information based on PCI ATS >> + * and PASID spec. > > "for example information based on PCI PRI and PASID extensions"? ATS+PRI > have been integrated into the main spec, and only PRI is relevant here. > >> + * - Un-recoverable faults of device interest > > "of interest to device drivers"? Simplified/Replaced by " * struct iommu_fault_event - Generic fault event * * Can represent recoverable faults such as a page requests or * unrecoverable faults such as DMA or IRQ remapping faults. " > >> + * - DMA remapping and IRQ remapping faults >> + * >> + * @fault: fault descriptor >> + * @iommu_private: used by the IOMMU driver for storing fault-specific >> + * data. Users should not modify this field before >> + * sending the fault response. >> + */ >> +struct iommu_fault_event { >> + struct iommu_fault fault; >> + u64 iommu_private; >> +}; >> + >> +/** >> + * struct iommu_fault_param - per-device IOMMU fault data >> + * @dev_fault_handler: Callback function to handle IOMMU faults at device level >> + * @data: handler private data >> + * >> + */ >> +struct iommu_fault_param { >> + iommu_dev_fault_handler_t handler; >> + void *data; >> +}; >> + >> +/** >> + * struct iommu_param - collection of per-device IOMMU data >> + * >> + * @fault_param: IOMMU detected device fault reporting data >> + * >> + * TODO: migrate other per device data pointers under iommu_dev_data, e.g. >> + * struct iommu_group *iommu_group; >> + * struct iommu_fwspec *iommu_fwspec; >> + */ >> +struct iommu_param { >> + struct iommu_fault_param *fault_param; >> +}; >> + >> int iommu_device_register(struct iommu_device *iommu); >> void iommu_device_unregister(struct iommu_device *iommu); >> int iommu_device_sysfs_add(struct iommu_device *iommu, >> @@ -418,6 +464,7 @@ struct iommu_ops {}; >> struct iommu_group {}; >> struct iommu_fwspec {}; >> struct iommu_device {}; >> +struct iommu_fault_param {}; >> >> static inline bool iommu_present(struct bus_type *bus) >> { >> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h >> new file mode 100644 >> index 000000000000..7ebf23ed6ccb >> --- /dev/null >> +++ b/include/uapi/linux/iommu.h >> @@ -0,0 +1,115 @@ >> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ >> +/* >> + * IOMMU user API definitions >> + */ >> + >> +#ifndef _UAPI_IOMMU_H >> +#define _UAPI_IOMMU_H >> + >> +#include >> + >> +/* 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, >> +}; >> + >> +/** >> + * Unrecoverable fault data >> + * @reason: reason of the fault >> + * @addr: offending page address >> + * @fetch_addr: address that caused a fetch abort, if any >> + * @pasid: contains process address space ID, used in shared virtual memory >> + * @perm: Requested permission access using by the incoming transaction >> + * IOMMU_FAULT_READ, IOMMU_FAULT_WRITE > > Stale comment removed > >> + */ >> +struct iommu_fault_unrecoverable { >> + __u32 reason; /* enum iommu_fault_reason */ >> +#define IOMMU_FAULT_UNRECOV_PASID_VALID (1 << 0) >> +#define IOMMU_FAULT_UNRECOV_PERM_VALID (1 << 1) > > Not needed, since @perm is already a bitfield not exactly, READ is encoded as 0. We need to differentiate read fault from no perm provided. However if I follow your recommendation below and transform the READ FAULT into a set bit this makes sense. > >> +#define IOMMU_FAULT_UNRECOV_ADDR_VALID (1 << 2) >> +#define IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID (1 << 3) >> + __u32 flags; >> + __u32 pasid; >> +#define IOMMU_FAULT_PERM_WRITE (1 << 0) /* write */ >> +#define IOMMU_FAULT_PERM_EXEC (1 << 1) /* exec */ >> +#define IOMMU_FAULT_PERM_PRIV (1 << 2) /* priviledged */ > > typo "privileged" OK > >> +#define IOMMU_FAULT_PERM_INST (1 << 3) /* instruction */ > > Could you move these outside the struct definition? They are shared with > the other struct. And it would be less confusing, from the device driver > point of view, to merge those with the existing IOMMU_FAULT_* defines > (but moving them to UAPI and making them bits) ok I will look at this. Need to check if the read fault value is not hardcoded anywhere. > >> + __u32 perm; >> + __u64 addr; >> + __u64 fetch_addr; >> +}; >> + >> +/* >> + * Page Request data (aka. recoverable fault data) >> + * @flags : encodes whether the pasid is valid and whether this >> + * is the last page in group >> + * @pasid: pasid >> + * @grpid: page request group index >> + * @perm: requested page permissions >> + * @addr: page address >> + */ >> +struct iommu_fault_page_request { >> +#define IOMMU_FAULT_PAGE_REQUEST_PASID_PRESENT (1 << 0) > > PASID_VALID, to be consistent with the other set of flags? OK > >> +#define IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE (1 << 1) >> +#define IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA (1 << 2) >> + __u32 flags; >> + __u32 pasid; >> + __u32 grpid; >> + __u32 perm; >> + __u64 addr; > > Given that we'll be reporting stall faults using this struct, it would > be good to have the fetch_addr field and flag here as well. OK > >> + __u64 private_data[2]; >> +}; >> + >> +/** >> + * struct iommu_fault - Generic fault data >> + * >> + * @type contains fault type >> + */ >> + >> +struct iommu_fault { >> + __u32 type; /* enum iommu_fault_type */ >> + __u32 reserved; >> + union { >> + struct iommu_fault_unrecoverable event; >> + struct iommu_fault_page_request prm; > > What's the 'm' in "prm"? Maybe just "pr"? This stands for page request message, I think this is the Intel's naming? Thank you for the review. Eric > > Thanks, > Jean > >> + }; >> +}; >> +#endif /* _UAPI_IOMMU_H */ >> >