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Date: Thu, 23 Apr 2015 16:38:04 +0800 From: "Li, ZhenHua" <zhen-hual@...com> To: "Li, ZhenHua" <zhen-hual@...com> CC: dwmw2@...radead.org, indou.takao@...fujitsu.com, bhe@...hat.com, joro@...tes.org, vgoyal@...hat.com, dyoung@...hat.com, iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org, kexec@...ts.infradead.org, alex.williamson@...hat.com, ddutile@...hat.com, ishii.hironobu@...fujitsu.com, bhelgaas@...gle.com, doug.hatch@...com, jerry.hoemann@...com, tom.vaden@...com, li.zhang6@...com, lisa.mitchell@...com, billsumnerlinux@...il.com, rwright@...com Subject: Re: [PATCH v10 0/10] iommu/vt-d: Fix intel vt-d faults in kdump kernel Tested on HP DL980. Result: Passed. PCI list and log are attached. dl980_boot.log: Log for first kernel. dl980_dump.log: Log for kdump kernel. lspci: log for command lspci Thanks Zhenhua On 04/23/2015 04:35 PM, Li, ZhenHua wrote: > Tested on HP Superdome X. > Result: Passed. > > PCI list and log are attached. > > superdomex_boot.log: Log for first kernel. > superdomex_dump.log: Log for kdump kernel. > lspci: log for command lspci > > Thanks > Zhenhua > On 04/10/2015 04:42 PM, Li, Zhen-Hua wrote: >> This patchset is an update of Bill Sumner's patchset, implements a fix >> for: >> If a kernel boots with intel_iommu=on on a system that supports intel >> vt-d, >> when a panic happens, the kdump kernel will boot with these faults: >> >> dmar: DRHD: handling fault status reg 102 >> dmar: DMAR:[DMA Read] Request device [01:00.0] fault addr fff80000 >> DMAR:[fault reason 01] Present bit in root entry is clear >> >> dmar: DRHD: handling fault status reg 2 >> dmar: INTR-REMAP: Request device [[61:00.0] fault index 42 >> INTR-REMAP:[fault reason 34] Present field in the IRTE entry is >> clear >> >> On some system, the interrupt remapping fault will also happen even if >> the >> intel_iommu is not set to on, because the interrupt remapping will be >> enabled >> when x2apic is needed by the system. >> >> The cause of the DMA fault is described in Bill's original version, >> and the >> INTR-Remap fault is caused by a similar reason. In short, the >> initialization >> of vt-d drivers causes the in-flight DMA and interrupt requests get wrong >> response. >> >> To fix this problem, we modifies the behaviors of the intel vt-d in the >> crashdump kernel: >> >> For DMA Remapping: >> 1. To accept the vt-d hardware in an active state, >> 2. Do not disable and re-enable the translation, keep it enabled. >> 3. Use the old root entry table, do not rewrite the RTA register. >> 4. Malloc and use new context entry table, copy data from the old ones >> that >> used by the old kernel. >> 5. Keep using the old page tables before driver is loaded. >> 6. After device driver is loaded, when it issues the first dma_map >> command, >> free the dmar_domain structure for this device, and generate a new >> one, so >> that the device can be assigned a new and empty page table. >> 7. When a new context entry table is generated, we also save its >> address to >> the old root entry table. >> >> For Interrupt Remapping: >> 1. To accept the vt-d hardware in an active state, >> 2. Do not disable and re-enable the interrupt remapping, keep it enabled. >> 3. Use the old interrupt remapping table, do not rewrite the IRTA >> register. >> 4. When ioapic entry is setup, the interrupt remapping table is >> changed, and >> the updated data will be stored to the old interrupt remapping table. >> >> Advantages of this approach: >> 1. All manipulation of the IO-device is done by the Linux device-driver >> for that device. >> 2. This approach behaves in a manner very similar to operation without an >> active iommu. >> 3. Any activity between the IO-device and its RMRR areas is handled by >> the >> device-driver in the same manner as during a non-kdump boot. >> 4. If an IO-device has no driver in the kdump kernel, it is simply >> left alone. >> This supports the practice of creating a special kdump kernel without >> drivers for any devices that are not required for taking a crashdump. >> 5. Minimal code-changes among the existing mainline intel vt-d code. >> >> Summary of changes in this patch set: >> 1. Added some useful function for root entry table in code intel-iommu.c >> 2. Added new members to struct root_entry and struct irte; >> 3. Functions to load old root entry table to iommu->root_entry from >> the memory >> of old kernel. >> 4. Functions to malloc new context entry table and copy the data from >> the old >> ones to the malloced new ones. >> 5. Functions to enable support for DMA remapping in kdump kernel. >> 6. Functions to load old irte data from the old kernel to the kdump >> kernel. >> 7. Some code changes that support other behaviours that have been listed. >> 8. In the new functions, use physical address as "unsigned long" type, >> not >> pointers. >> >> Original version by Bill Sumner: >> https://lkml.org/lkml/2014/1/10/518 >> https://lkml.org/lkml/2014/4/15/716 >> https://lkml.org/lkml/2014/4/24/836 >> >> Zhenhua's updates: >> https://lkml.org/lkml/2014/10/21/134 >> https://lkml.org/lkml/2014/12/15/121 >> https://lkml.org/lkml/2014/12/22/53 >> https://lkml.org/lkml/2015/1/6/1166 >> https://lkml.org/lkml/2015/1/12/35 >> https://lkml.org/lkml/2015/3/19/33 >> >> Changelog[v10]: >> 1. Do not use CONFIG_CRASH_DUMP and is_kdump_kernel(). >> Use one flag which stores the te and ir status in last kernel: >> iommu->pre_enabled_trans >> iommu->pre_enabled_ir >> >> Changelog[v9]: >> 1. Add new function iommu_attach_domain_with_id. >> 2. Do not copy old page tables, keep using the old ones. >> 3. Remove functions: >> intel_iommu_did_to_domain_values_entry >> intel_iommu_get_dids_from_old_kernel >> device_to_domain_id >> copy_page_addr >> copy_page_table >> copy_context_entry >> copy_context_entry_table >> 4. Add new function device_to_existing_context_entry. >> >> Changelog[v8]: >> 1. Add a missing __iommu_flush_cache in function copy_page_table. >> >> Changelog[v7]: >> 1. Use __iommu_flush_cache to flush the data to hardware. >> >> Changelog[v6]: >> 1. Use "unsigned long" as type of physical address. >> 2. Use new function unmap_device_dma to unmap the old dma. >> 3. Some small incorrect bits order for aw shift. >> >> Changelog[v5]: >> 1. Do not disable and re-enable traslation and interrupt remapping. >> 2. Use old root entry table. >> 3. Use old interrupt remapping table. >> 4. New functions to copy data from old kernel, and save to old >> kernel mem. >> 5. New functions to save updated root entry table and irte table. >> 6. Use intel_unmap to unmap the old dma; >> 7. Allocate new pages while driver is being loaded. >> >> Changelog[v4]: >> 1. Cut off the patches that move some defines and functions to >> new files. >> 2. Reduce the numbers of patches to five, make it more easier to >> read. >> 3. Changed the name of functions, make them consistent with >> current context >> get/set functions. >> 4. Add change to function __iommu_attach_domain. >> >> Changelog[v3]: >> 1. Commented-out "#define DEBUG 1" to eliminate debug messages. >> 2. Updated the comments about changes in each version. >> 3. Fixed: one-line added to Copy-Translations patch to initialize >> the iovad >> struct as recommended by Baoquan He [bhe@...hat.com] >> init_iova_domain(&domain->iovad, DMA_32BIT_PFN); >> >> Changelog[v2]: >> The following series implements a fix for: >> A kdump problem about DMA that has been discussed for a long >> time. That is, >> when a kernel panics and boots into the kdump kernel, DMA started >> by the >> panicked kernel is not stopped before the kdump kernel is booted >> and the >> kdump kernel disables the IOMMU while this DMA continues. This >> causes the >> IOMMU to stop translating the DMA addresses as IOVAs and begin to >> treat >> them as physical memory addresses -- which causes the DMA to either: >> (1) generate DMAR errors or >> (2) generate PCI SERR errors or >> (3) transfer data to or from incorrect areas of memory. Often >> this >> causes the dump to fail. >> >> Changelog[v1]: >> The original version. >> >> Changed in this version: >> 1. Do not disable and re-enable traslation and interrupt remapping. >> 2. Use old root entry table. >> 3. Use old interrupt remapping table. >> 4. Use "unsigned long" as physical address. >> 5. Use intel_unmap to unmap the old dma; >> >> Baoquan He <bhe@...hat.com> helps testing this patchset. >> Takao Indoh <indou.takao@...fujitsu.com> gives valuable suggestions. >> >> Li, Zhen-Hua (10): >> iommu/vt-d: New function to attach domain with id >> iommu/vt-d: Items required for kdump >> iommu/vt-d: Function to get old context entry >> iommu/vt-d: functions to copy data from old mem >> iommu/vt-d: Add functions to load and save old re >> iommu/vt-d: datatypes and functions used for kdump >> iommu/vt-d: enable kdump support in iommu module >> iommu/vt-d: assign new page table for dma_map >> iommu/vt-d: Copy functions for irte >> iommu/vt-d: Use old irte in kdump kernel >> >> drivers/iommu/intel-iommu.c | 518 >> ++++++++++++++++++++++++++++++++++-- >> drivers/iommu/intel_irq_remapping.c | 96 ++++++- >> include/linux/intel-iommu.h | 16 ++ >> 3 files changed, 605 insertions(+), 25 deletions(-) >> > View attachment "dl980_boot.log" of type "text/x-log" (99170 bytes) View attachment "dl980_dump.log" of type "text/x-log" (94879 bytes) View attachment "lspci" of type "text/plain" (3253 bytes)
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