Re: [RFC RESEND 00/16] Split IOMMU DMA mapping operation to two steps

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Mar 08, 2024 at 04:23:42PM -0400, Jason Gunthorpe wrote:
> > The DMA API callers really need to know what is P2P or not for
> > various reasons.  And they should generally have that information
> > available, either from pin_user_pages that needs to special case
> > it or from the in-kernel I/O submitter that build it from P2P and
> > normal memory.
> 
> I think that is a BIO thing. RDMA just calls with FOLL_PCI_P2PDMA and
> shoves the resulting page list into in a scattertable. It never checks
> if any returned page is P2P - it has no reason to care. dma_map_sg()
> does all the work.

Right now it does, but that's not really a good interface.  If we have
a pin_user_pages variant that only pins until the next relevant P2P
boundary and tells you about we can significantly simplify the overall
interface.




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux