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Subject[PATCH 0/6] iommu: Enable devices to request non-strict DMA, starting with QCom SD/MMC
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This patch attempts to put forward a proposal for enabling non-strict
DMA on a device-by-device basis. The patch series requests non-strict
DMA for the Qualcomm SDHCI controller as a first device to enable,
getting a nice bump in performance with what's believed to be a very
small drop in security / safety (see the patch for the full argument).

As part of this patch series I am end up slightly cleaning up some of
the interactions between the PCI subsystem and the IOMMU subsystem but
I don't go all the way to fully remove all the tentacles. Specifically
this patch series only concerns itself with a single aspect: strict
vs. non-strict mode for the IOMMU. I'm hoping that this will be easier
to talk about / reason about for more subsystems compared to overall
deciding what it means for a device to be "external" or "untrusted".

If something like this patch series ends up being landable, it will
undoubtedly need coordination between many maintainers to land. I
believe it's fully bisectable but later patches in the series
definitely depend on earlier ones. Sorry for the long CC list. :(


Douglas Anderson (6):
drivers: base: Add the concept of "pre_probe" to drivers
drivers: base: Add bits to struct device to control iommu strictness
PCI: Indicate that we want to force strict DMA for untrusted devices
iommu: Combine device strictness requests with the global default
iommu: Stop reaching into PCIe devices to decide strict vs. non-strict
mmc: sdhci-msm: Request non-strict IOMMU mode

drivers/base/dd.c | 10 +++++--
drivers/iommu/dma-iommu.c | 2 +-
drivers/iommu/iommu.c | 56 +++++++++++++++++++++++++++--------
drivers/mmc/host/sdhci-msm.c | 8 +++++
drivers/pci/probe.c | 4 ++-
include/linux/device.h | 11 +++++++
include/linux/device/driver.h | 9 ++++++
include/linux/iommu.h | 2 ++
8 files changed, 85 insertions(+), 17 deletions(-)

--
2.32.0.288.g62a8d224e6-goog

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