[dpdk-dev] [PATCH v4 02/15] mem: introduce IOVA type

Thomas Monjalon thomas at monjalon.net
Mon Nov 6 09:37:27 CET 2017


06/11/2017 06:38, santosh:
> 
> On Monday 06 November 2017 07:11 AM, Thomas Monjalon wrote:
> > The IO virtual addresses may be used instead of physical addresses.
> > As IOVA is more generic, it should be used in most places instead
> > of physical address wording.
> >
> > Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
> > ---
> > +/**
> > + * IO virtual address type.
> > + * When the physical addressing mode is in use,
> > + * the translation from a virtual address to a physical address
> > + * is a direct mapping, i.e. the same value.
> > + */
> 
> I guess - that description applicable for iova=va mode
> and for iova=pa mode - Need to do explicit virt2phy translation.
> I believe you mis-wrote - s/physical addressing mode/virtual addressing mode.

Not sure to understand your comment.
Let me reword the description to be less ambiguous:

* When the physical addressing mode (IOVA as PA) is in use,
* the translation from an IO virtual address (IOVA) to a physical address
* is a direct mapping, i.e. the same value.
* Otherwise, in virtual mode (IOVA as VA), an IOMMU may do the translation.

Is this description correct?



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