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| author | Jean-Philippe Brucker <jean-philippe@linaro.org> | 2020-11-06 16:50:49 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-11-23 14:16:55 +0000 |
| commit | 32784a9562fb0518b12e9797ee2aec52214adf6f (patch) | |
| tree | dde982dd0481b5ba75c84873d0f7c604565b5f2e /drivers/iommu/Kconfig | |
| parent | cfc78dfd9b36dcda7c3ca9cdfca343f84c72252f (diff) | |
| download | lwn-32784a9562fb0518b12e9797ee2aec52214adf6f.tar.gz lwn-32784a9562fb0518b12e9797ee2aec52214adf6f.zip | |
iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()
The sva_bind() function allows devices to access process address spaces
using a PASID (aka SSID).
(1) bind() allocates or gets an existing MMU notifier tied to the
(domain, mm) pair. Each mm gets one PASID.
(2) Any change to the address space calls invalidate_range() which sends
ATC invalidations (in a subsequent patch).
(3) When the process address space dies, the release() notifier disables
the CD to allow reclaiming the page tables. Since release() has to
be light we do not instruct device drivers to stop DMA here, we just
ignore incoming page faults from this point onwards.
To avoid any event 0x0a print (C_BAD_CD) we disable translation
without clearing CD.V. PCIe Translation Requests and Page Requests
are silently denied. Don't clear the R bit because the S bit can't
be cleared when STALL_MODEL==0b10 (forced), and clearing R without
clearing S is useless. Faulting transactions will stall and will be
aborted by the IOPF handler.
(4) After stopping DMA, the device driver releases the bond by calling
unbind(). We release the MMU notifier, free the PASID and the bond.
Three structures keep track of bonds:
* arm_smmu_bond: one per {device, mm} pair, the handle returned to the
device driver for a bind() request.
* arm_smmu_mmu_notifier: one per {domain, mm} pair, deals with ATS/TLB
invalidations and clearing the context descriptor on mm exit.
* arm_smmu_ctx_desc: one per mm, holds the pinned ASID and pgd.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20201106155048.997886-4-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/iommu/Kconfig')
| -rw-r--r-- | drivers/iommu/Kconfig | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index f5ebbdfbf636..192ef8f61310 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -316,6 +316,8 @@ config ARM_SMMU_V3 config ARM_SMMU_V3_SVA bool "Shared Virtual Addressing support for the ARM SMMUv3" depends on ARM_SMMU_V3 + select IOMMU_SVA_LIB + select MMU_NOTIFIER help Support for sharing process address spaces with devices using the SMMUv3. |