xen/biomerge: Don't allow biovec's to be merged when Linux is not using 4KB pages
On ARM all dma-capable devices on a same platform may not be protected by an IOMMU. The DMA requests have to use the BFN (i.e MFN on ARM) in order to use correctly the device. While the DOM0 memory is allocated in a 1:1 fashion (PFN == MFN), grant mapping will screw this contiguous mapping. When Linux is using 64KB page granularitary, the page may be split accross multiple non-contiguous MFN (Xen is using 4KB page granularity). Therefore a DMA request will likely fail. Checking that a 64KB page is using contiguous MFN is tedious. For now, always says that biovec are not mergeable. Signed-off-by:Julien Grall <julien.grall@citrix.com> Reviewed-by:
Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by:
David Vrabel <david.vrabel@citrix.com>
parent
4f503fbd
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