| Message ID | 20190407124147.13576-1-thunder.leizhen@huawei.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | normalize IOMMU dma mode boot options | expand |
Hi Zhen, On 2019/4/7 20:41, Zhen Lei wrote: > As Robin Murphy's suggestion: > "It's also not necessarily obvious to the user how this interacts with > IOMMU_DEFAULT_PASSTHROUGH, so if we really do go down this route, maybe it > would be better to refactor the whole lot into a single selection of something > like IOMMU_DEFAULT_MODE anyway." > > In this version, I tried to normalize the IOMMU dma mode boot options for all > ARCHs. When IOMMU is enabled, there are 3 dma modes: paasthrough(bypass), > lazy(mapping but defer the IOTLB invalidation), strict. But currently each > ARCHs defined their private boot options, different with each other. For > example, to enable/disable "passthrough", ARM64 use iommu.passthrough=1/0, > X86 use iommu=pt/nopt, PPC/POWERNV use iommu=nobypass. > > > Zhen Lei (6): > iommu: use iommu.dma_mode to replace iommu.passthrough and > iommu.strict > iommu: keep dma mode build options consistent with cmdline options > iommu: add iommu_default_dma_mode_get() helper > s390/pci: use common boot option iommu.dma_mode > powernv/iommu: use common boot option iommu.dma_mode > x86/iommu: use common boot option iommu.dma_mode This will break systems using boot options as now, and I think this is unacceptable. If you want to do so, just introduce iommu.dma_mode on top of those iommu boot options with dma mode boot options unchanged, and iommu.dma_mode is for all archs but compatible with them. Thanks Hanjun
On 2019/4/8 9:14, Hanjun Guo wrote: > Hi Zhen, > > On 2019/4/7 20:41, Zhen Lei wrote: >> As Robin Murphy's suggestion: >> "It's also not necessarily obvious to the user how this interacts with >> IOMMU_DEFAULT_PASSTHROUGH, so if we really do go down this route, maybe it >> would be better to refactor the whole lot into a single selection of something >> like IOMMU_DEFAULT_MODE anyway." >> >> In this version, I tried to normalize the IOMMU dma mode boot options for all >> ARCHs. When IOMMU is enabled, there are 3 dma modes: paasthrough(bypass), >> lazy(mapping but defer the IOTLB invalidation), strict. But currently each >> ARCHs defined their private boot options, different with each other. For >> example, to enable/disable "passthrough", ARM64 use iommu.passthrough=1/0, >> X86 use iommu=pt/nopt, PPC/POWERNV use iommu=nobypass. >> >> >> Zhen Lei (6): >> iommu: use iommu.dma_mode to replace iommu.passthrough and >> iommu.strict >> iommu: keep dma mode build options consistent with cmdline options >> iommu: add iommu_default_dma_mode_get() helper >> s390/pci: use common boot option iommu.dma_mode >> powernv/iommu: use common boot option iommu.dma_mode >> x86/iommu: use common boot option iommu.dma_mode > > This will break systems using boot options as now, and I think > this is unacceptable. If you want to do so, just introduce iommu.dma_mode > on top of those iommu boot options with dma mode boot options unchanged, > and iommu.dma_mode is for all archs but compatible with them. I just changed the boot options name, but keep the function no change. I added all related maintainers/supporters in the "to=" list, maybe we can disuss this. Should I add some "obsoleted" warnings for old options and keep them for a while? But I think this kind of thing is best done in one go. > > Thanks > Hanjun > > > . >
On Mon, 8 Apr 2019, Leizhen (ThunderTown) wrote: > > > > This will break systems using boot options as now, and I think > > this is unacceptable. If you want to do so, just introduce iommu.dma_mode > > on top of those iommu boot options with dma mode boot options unchanged, > > and iommu.dma_mode is for all archs but compatible with them. > > I just changed the boot options name, but keep the function no change. I added > all related maintainers/supporters in the "to=" list, maybe we can disuss this. Changing the name _IS_ the problem. Think about unattended updates. > Should I add some "obsoleted" warnings for old options and keep them for a while? No, just keep the old options around for backwards compatibilty sake. We just do not add new arch specific options in the future. New options need to use the generic iommu.dma_mode name space. Thanks, tglx
On 2019/4/8 14:32, Thomas Gleixner wrote: > On Mon, 8 Apr 2019, Leizhen (ThunderTown) wrote: >>> >>> This will break systems using boot options as now, and I think >>> this is unacceptable. If you want to do so, just introduce iommu.dma_mode >>> on top of those iommu boot options with dma mode boot options unchanged, >>> and iommu.dma_mode is for all archs but compatible with them. >> >> I just changed the boot options name, but keep the function no change. I added >> all related maintainers/supporters in the "to=" list, maybe we can disuss this. > > Changing the name _IS_ the problem. Think about unattended updates. > >> Should I add some "obsoleted" warnings for old options and keep them for a while? > > No, just keep the old options around for backwards compatibilty sake. We > just do not add new arch specific options in the future. New options need > to use the generic iommu.dma_mode name space. OK, thanks for your advise. > > Thanks, > > tglx > > . >
As Robin Murphy's suggestion: "It's also not necessarily obvious to the user how this interacts with IOMMU_DEFAULT_PASSTHROUGH, so if we really do go down this route, maybe it would be better to refactor the whole lot into a single selection of something like IOMMU_DEFAULT_MODE anyway." In this version, I tried to normalize the IOMMU dma mode boot options for all ARCHs. When IOMMU is enabled, there are 3 dma modes: paasthrough(bypass), lazy(mapping but defer the IOTLB invalidation), strict. But currently each ARCHs defined their private boot options, different with each other. For example, to enable/disable "passthrough", ARM64 use iommu.passthrough=1/0, X86 use iommu=pt/nopt, PPC/POWERNV use iommu=nobypass. Zhen Lei (6): iommu: use iommu.dma_mode to replace iommu.passthrough and iommu.strict iommu: keep dma mode build options consistent with cmdline options iommu: add iommu_default_dma_mode_get() helper s390/pci: use common boot option iommu.dma_mode powernv/iommu: use common boot option iommu.dma_mode x86/iommu: use common boot option iommu.dma_mode Documentation/admin-guide/kernel-parameters.txt | 42 +++++++------------- arch/ia64/include/asm/iommu.h | 2 - arch/ia64/kernel/pci-dma.c | 2 - arch/powerpc/platforms/powernv/pci-ioda.c | 23 +---------- arch/s390/pci/pci_dma.c | 20 +++------- arch/x86/include/asm/iommu.h | 1 - arch/x86/kernel/pci-dma.c | 20 ---------- drivers/iommu/Kconfig | 36 ++++++++++++++--- drivers/iommu/amd_iommu.c | 12 +++--- drivers/iommu/amd_iommu_init.c | 4 -- drivers/iommu/amd_iommu_types.h | 6 --- drivers/iommu/intel-iommu.c | 7 +--- drivers/iommu/iommu.c | 52 ++++++++++++++++--------- include/linux/iommu.h | 16 ++++++++ 14 files changed, 108 insertions(+), 135 deletions(-)