Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
30 lines
1.1 KiB
Plaintext
30 lines
1.1 KiB
Plaintext
What: /sys/bus/pci/drivers/uio_pci_sva/<pci_dev>/pasid
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Date: September 2025
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Contact: Yaxing Guo <guoyaxing@bosc.ac.cn>
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Description:
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Process Address Space ID (PASID) assigned by IOMMU driver to
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the device for use with Shared Virtual Addressing (SVA).
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This read-only attribute exposes the PASID (A 20-bit identifier
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used in PCIe Address Translation Services and iommu table walks)
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allocated by the IOMMU driver during sva device binding.
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User-space UIO applications must read this attribute to obtain
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the PASID and program it into the device's configuration registers.
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This enables the device to perform DMA using user-space virtual
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address, with address translation handled by IOMMU.
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UIO User-space applications must:
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- Opening device and Mapping the device's register space via /dev/uioX
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(This triggers the IOMMU driver to allocate the PASID)
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- Reading the PASID from sysfs
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- Writing the PASID to a device-specific register (with example offset)
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The code may be like:
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map = mmap(..., "/dev/uio0", ...);
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f = fopen("/sys/.../pasid", "r");
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fscanf(f, "%d", &pasid);
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map[REG_PASID_OFFSET] = pasid;
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