iommu_map takes offset and size parameters, and promises to allocate a range that satisfies boundary constraints. iommu_bus_dmamap_load_something1 adds offset to size before calling iommu_map, and shrinks the result by offset, perhaps to work around a bug that was in iommu_map before commit 11fced21ccea1b80327d159a4c27046cb1f46952. This change removes that addition and subtraction of offset to avoid requiring a larger address range than necessary.
Details
Details
Peter, a run with DMAR turned on, please.
Diff Detail
Diff Detail
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To test, ask Peter Holm to do a run with DMAR turned on.
| sys/dev/iommu/busdma_iommu.c | ||
|---|---|---|
| 619 | I agree with the removal of the asserts and the clip above this one, but IMO tag maxsegsz check should be kept, at least in the form of the assert. | |
| sys/dev/iommu/busdma_iommu.c | ||
|---|---|---|
| 619 | The maxsegsz assert is still there, at line 639(before)/605(after). | |
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iommu_map->iommu_gas_map->iommu_gas_find_space requires that the size parameter be a multiple of page size, so restore the round-up to respect that.
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panic: segment too large: ctx 0xfffff800041ca180 start 0xfef01000 end 0xfef24000 buflen1 0x23000 maxsegsz 0x22400
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I guess rounding buflen1 up to a multiple of page size, when maxsegsz is not a multiple of page size, is a problem. So restore check to reduce buflen1 to maxsegsz.
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Kernel page fault with the following non-sleepable locks held: exclusive rw vm object (vm object) r = 0 (0xfffff80004837b58) locked @ x86/iommu/intel_idpgtbl.c:550 exclusive sleep mutex AHCI channel lock (AHCI channel lock) r = 0 (0xfffffe003ce28400) locked @ kern/kern_mutex.c:211 stack backtrace: #0 0xffffffff80c85445 at witness_debugger+0x65 #1 0xffffffff80c8659a at witness_warn+0x3ea #2 0xffffffff810fcce6 at trap_pfault+0x86 #3 0xffffffff810cdc18 at calltrap+0x8 #4 0xffffffff81078e7e at iommu_gas_map+0x15e #5 0xffffffff81077339 at iommu_bus_dmamap_load_something+0x119 #6 0xffffffff81076995 at iommu_bus_dmamap_load_buffer+0x1c5 #7 0xffffffff80c55a3e at _bus_dmamap_load_ccb+0x20e #8 0xffffffff80c557cc at bus_dmamap_load_ccb+0x8c #9 0xffffffff803929d9 at xpt_run_devq+0x2f9 #10 0xffffffff80395de7 at xpt_release_simq+0x67 #11 0xffffffff80c3027a at softclock_call_cc+0x15a #12 0xffffffff80c31b96 at softclock_thread+0xc6 #13 0xffffffff80bc9850 at fork_exit+0x80 #14 0xffffffff810cec8e at fork_trampoline+0xe
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Remove 'offset' in computing initial size, but not when when examining iommu_map product.
Comment Actions
Remove the material part of this patch, because a stealth reviewer finds a bug in it, and leave only the style bits which do simplify some obscure code.
| sys/dev/iommu/busdma_iommu.c | ||
|---|---|---|
| 601–603 | I would recommend adding a comment here to say that this is handling a split buffer. | |