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2022-02-15iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exitFenghua Yu1-1/+0
PASIDs are process-wide. It was attempted to use refcounted PASIDs to free them when the last thread drops the refcount. This turned out to be complex and error prone. Given the fact that the PASID space is 20 bits, which allows up to 1M processes to have a PASID associated concurrently, PASID resource exhaustion is not a realistic concern. Therefore, it was decided to simplify the approach and stick with lazy on demand PASID allocation, but drop the eager free approach and make an allocated PASID's lifetime bound to the lifetime of the process. Get rid of the refcounting mechanisms and replace/rename the interfaces to reflect this new approach. [ bp: Massage commit message. ] Suggested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Joerg Roedel <jroedel@suse.de> Link: https://lore.kernel.org/r/20220207230254.3342514-6-fenghua.yu@intel.com
2022-02-14iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVAFenghua Yu1-3/+3
This CONFIG option originally only referred to the Shared Virtual Address (SVA) library. But it is now also used for non-library portions of code. Drop the "_LIB" suffix so that there is just one configuration option for all code relating to SVA. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20220207230254.3342514-2-fenghua.yu@intel.com
2021-04-07iommu: Add a page fault handlerJean-Philippe Brucker1-0/+53
Some systems allow devices to handle I/O Page Faults in the core mm. For example systems implementing the PCIe PRI extension or Arm SMMU stall model. Infrastructure for reporting these recoverable page faults was added to the IOMMU core by commit 0c830e6b3282 ("iommu: Introduce device fault report API"). Add a page fault handler for host SVA. IOMMU driver can now instantiate several fault workqueues and link them to IOPF-capable devices. Drivers can choose between a single global workqueue, one per IOMMU device, one per low-level fault queue, one per domain, etc. When it receives a fault event, most commonly in an IRQ handler, the IOMMU driver reports the fault using iommu_report_device_fault(), which calls the registered handler. The page fault handler then calls the mm fault handler, and reports either success or failure with iommu_page_response(). After the handler succeeds, the hardware retries the access. The iopf_param pointer could be embedded into iommu_fault_param. But putting iopf_param into the iommu_param structure allows us not to care about ordering between calls to iopf_queue_add_device() and iommu_register_device_fault_handler(). Tested-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Link: https://lore.kernel.org/r/20210401154718.307519-7-jean-philippe@linaro.org Signed-off-by: Joerg Roedel <jroedel@suse.de>
2020-11-23iommu/sva: Add PASID helpersJean-Philippe Brucker1-0/+15
Let IOMMU drivers allocate a single PASID per mm. Store the mm in the IOASID set to allow refcounting and searching mm by PASID, when handling an I/O page fault. Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20201106155048.997886-3-jean-philippe@linaro.org Signed-off-by: Will Deacon <will@kernel.org>