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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c84982adb2
We have a few cases where we need to extend the data returned from the INFO ioctls in VFIO. For instance we already have devices exposed through vfio-pci where VFIO_DEVICE_GET_REGION_INFO reports the region as mmap-capable, but really only supports sparse mmaps, avoiding the MSI-X table. If we wanted to provide in-kernel emulation or extended functionality for devices, we'd also want the ability to tell the user not to mmap various regions, rather than forcing them to figure it out on their own. Another example is VFIO_IOMMU_GET_INFO. We'd really like to expose the actual IOVA capabilities of the IOMMU rather than letting the user assume the address space they have available to them. We could add IOVA base and size fields to struct vfio_iommu_type1_info, but what if we have multiple IOVA ranges. For instance x86 uses a range of addresses at 0xfee00000 for MSI vectors. These typically are not available for standard DMA IOVA mappings and splits our available IOVA space into two ranges. POWER systems have both an IOVA window below 4G as well as dynamic data window which they can use to remap all of guest memory. Representing variable sized arrays within a fixed structure makes it very difficult to parse, we'd therefore like to put this data beyond fixed fields within the data structures. One way to do this is to emulate capabilities in PCI configuration space. A new flag indciates whether capabilties are supported and a new fixed field reports the offset of the first entry. Users can then walk the chain to find capabilities, adding capabilities does not require additional fields in the fixed structure, and parsing variable sized data becomes trivial. This patch outlines the theory and base header structure, which should be shared by all future users. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> |
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| .. | ||
| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| video | ||
| xen | ||
| Kbuild | ||