On Wed, 2012-07-11 at 09:55 +1000, Alexey Kardashevskiy wrote:
> On 11/07/12 08:26, Scott Wood wrote:
> > On 07/10/2012 12:51 AM, Alexey Kardashevskiy wrote:
> >> The patch enables VFIO on POWER.
> >>
> >> It literally does the following:
> >>
> >> 1. POWERPC IOMMU support (the kernel counterpart is required)
> > [snip]
> >> +/* -------- API for POWERPC IOMMU -------- */
> >> +
> >> +#define POWERPC_IOMMU 2
> >> +
> >> +struct tce_iommu_info {
> >> + __u32 argsz;
> >> + __u32 dma32_window_start;
> >> + __u32 dma32_window_size;
> >> +};
> >> +
> >> +#define POWERPC_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
> >
> > Is there a more specific name that could be used for this? Not all
> > PowerPC chips have the same kind of IOMMU.
>
> Ben, is is SPAPR? BOOK3S?
So we have varieties of different iommus in the kernel indeed, we
probably want the info ioctl to reflect that. I would call this one
spapr_tce.
Also we will want a few other things, dunno if that's reflected here,
or whether the ioctl is easily extendable, but in the long run we will
need:
- Ways to tell KVM about association between a liobn (logical bus
number as used in H_PUT_TCE) and an iommu so we can implement the real
mode H_PUT_TCE properly.
- We will need some conduit to implement the "DDW" APIs (part of PAPR
allowing the guest to control the DMA windows, ie, by creating new
windows in 64-bit DMA space, with different page sizes etc....). So you
may want to make it clear that the above provides information about the
"base window" specifically.
Cheers,
Ben.
