On Sun, Feb 27, 2022 at 7:31 PM Christoph Hellwig <hch@xxxxxx> wrote: > > The IOMMU table tries to separate the different IOMMUs into different > backends, but actually requires various cross calls. > > Rewrite the code to do the generic swiotlb/swiotlb-xen setup directly > in pci-dma.c and then just call into the IOMMU drivers. ... > --- a/arch/x86/include/asm/iommu_table.h > +++ /dev/null > @@ -1,102 +0,0 @@ > -/* SPDX-License-Identifier: GPL-2.0 */ > -#ifndef _ASM_X86_IOMMU_TABLE_H > -#define _ASM_X86_IOMMU_TABLE_H > - > -#include <asm/swiotlb.h> > - > -/* > - * History lesson: > - * The execution chain of IOMMUs in 2.6.36 looks as so: > - * > - * [xen-swiotlb] > - * | > - * +----[swiotlb *]--+ > - * / | \ > - * / | \ > - * [GART] [Calgary] [Intel VT-d] > - * / > - * / > - * [AMD-Vi] > - * > - * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip > - * over the rest of IOMMUs and unconditionally initialize the SWIOTLB. > - * Also it would surreptitiously initialize set the swiotlb=1 if there were > - * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb > - * flag would be turned off by all IOMMUs except the Calgary one. > - * > - * The IOMMU_INIT* macros allow a similar tree (or more complex if desired) > - * to be built by defining who we depend on. > - * > - * And all that needs to be done is to use one of the macros in the IOMMU > - * and the pci-dma.c will take care of the rest. > - */ Christoph, Is it possible to keep documentation comments in source files? Or are they completely irrelevant now? Thanks.
