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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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16c11325cc
Current bus notifier in ARM64 (__iommu_attach_notifier)
attempts to attach dma_ops to a device on BUS_NOTIFY_ADD_DEVICE
action notification.
This will cause issues on ACPI based systems, where PCI devices
can be added before the IOMMUs the devices are attached to
had a chance to be probed, causing failures on attempts to
attach dma_ops in that the domain for the respective IOMMU
may not be set-up yet by the time the bus notifier is run.
Devices dma_ops do not require to be set-up till the matching
device drivers are probed. This means that instead of running
the notifier attaching dma_ops to devices (__iommu_attach_notifier)
on BUS_NOTIFY_ADD_DEVICE action, it can be run just before the
device driver is bound to the device in question (on action
BUS_NOTIFY_BIND_DRIVER) so that it is certain that its IOMMU
group and domain are set-up accordingly at the time the
notifier is triggered.
This patch changes the notifier action upon which dma_ops
are attached to devices and defer it to driver binding time,
so that IOMMU devices have a chance to be probed and to register
their bus notifiers before the dma_ops attach sequence for a
device is actually carried out.
As a result we also no longer need worry about racing with
iommu_bus_notifier(), or about retrying the queue in case devices
were added too early on DT-based systems, so clean up the notifier
itself plus the additional workaround from
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| .. | ||
| cache.S | ||
| context.c | ||
| copypage.c | ||
| dma-mapping.c | ||
| dump.c | ||
| extable.c | ||
| fault.c | ||
| flush.c | ||
| hugetlbpage.c | ||
| init.c | ||
| ioremap.c | ||
| kasan_init.c | ||
| Makefile | ||
| mm.h | ||
| mmap.c | ||
| mmu.c | ||
| numa.c | ||
| pageattr.c | ||
| pgd.c | ||
| proc.S | ||