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Our current strategy for pass-through mode is to put all devices into the 1:1 domain at startup (which is before we know what their dma_mask will be), and only _later_ take them out of that domain, if it turns out that they really can't address all of memory. However, when there are a bunch of PCI devices behind a bridge, they all end up with the same source-id on their DMA transactions, and hence in the same IOMMU domain. This means that we _can't_ easily move them from the 1:1 domain into their own domain at runtime, because there might be DMA in-flight from their siblings. So we have to adjust our pass-through strategy: For PCI devices not on the root bus, and for the bridges which will take responsibility for their transactions, we have to start up _out_ of the 1:1 domain, just in case. This fixes the BUG() we see when we have 32-bit-capable devices behind a PCI-PCI bridge, and use the software identity mapping. It does mean that we might end up using 'normal' mapping mode for some devices which could actually live with the faster 1:1 mapping -- but this is only for PCI devices behind bridges, which presumably aren't the devices for which people are most concerned about performance. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> |
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.. | ||
hotplug | ||
pcie | ||
.gitignore | ||
access.c | ||
bus.c | ||
dmar.c | ||
hotplug-pci.c | ||
hotplug.c | ||
htirq.c | ||
intel-iommu.c | ||
intr_remapping.c | ||
intr_remapping.h | ||
iov.c | ||
iova.c | ||
irq.c | ||
Kconfig | ||
Makefile | ||
msi.c | ||
msi.h | ||
pci-acpi.c | ||
pci-driver.c | ||
pci-stub.c | ||
pci-sysfs.c | ||
pci.c | ||
pci.h | ||
probe.c | ||
proc.c | ||
quirks.c | ||
remove.c | ||
rom.c | ||
search.c | ||
setup-bus.c | ||
setup-irq.c | ||
setup-res.c | ||
slot.c | ||
syscall.c |