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When using vfio to pass through a PCIe device (e.g. a GPU card) that has a huge BAR (e.g. 16GB), a lot of cycles are wasted on memory pinning because PFNs of PCI BAR are not backed by struct page, and the corresponding VMA has flag VM_PFNMAP. With this change, when pinning a region which is a raw PFN mapping, it can skip unnecessary user memory pinning process, and thus, can significantly improve VM's boot up time when passing through devices via VFIO. In my test on a Xeon E5 2.6GHz, the time mapping a 16GB BAR was reduced from about 0.4s to 1.5us. Signed-off-by: Jason Cai (Xiang Feng) <jason.cai@linux.alibaba.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> |
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| .. | ||
| mdev | ||
| pci | ||
| platform | ||
| Kconfig | ||
| Makefile | ||
| vfio_iommu_spapr_tce.c | ||
| vfio_iommu_type1.c | ||
| vfio_spapr_eeh.c | ||
| vfio.c | ||
| virqfd.c | ||