On Mon, Jun 04, 2007 at 05:43:02PM -0400, Guy Zana wrote:
>
>
> > -----Original Message-----
> > From: Muli Ben-Yehuda [mailto:muli@xxxxxxxxxx]
> > Sent: Monday, June 04, 2007 9:26 PM
> > To: Guy Zana
> > Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Xen-devel] [RFC][PATCH 1/6] HVM PCI Passthrough
> > (non-IOMMU)
> >
> > > +
> > > +# PCI pass-through flags
> > > +mapping_1to1 ?= y
> > > +passthrough ?= y
> >
> > Does one make sense without the other?
>
> Actually yes, you'll need the 1:1 layout only when using devices
> that needs DMA. Just the passthorugh switch could be turned on for
> other devices...
I think we take it as a given that passthrough (whether through 1:1 or
IOMMU support) will be compiled into Xen, so no need for a separate
flag.
> > > XEN_COMPILE_ARCH ?= $(shell uname -m | sed -e s/i.86/x86_32/ \
> > > -e s/ppc/powerpc/ -e s/i86pc/x86_32/)
> > > @@ -9,7 +13,7 @@ XEN_OS ?= $(shell uname -s)
> > > XEN_OS ?= $(shell uname -s)
> > >
> > > ifeq ($(XEN_TARGET_ARCH),x86_32)
> > > -XEN_TARGET_X86_PAE ?= y
> > > +XEN_TARGET_X86_PAE ?= n
> >
> > Is there a dependency between 1-1 / passthrough and !PAE, or
> > is this just for convenience?
>
> There is a dependency, not that it's that a problem to support PAE,
> we just didn't implement it yet. We decided to support x86_64 and
> remove the x86_32 / PAE support, as we see it, there is just no need
> to support x86_32 / PAE anymore...
Ok, just for reference, if there's a dependency in the future, it
should be expressed that way (only turn on PAE if 1:1 is on, in this
case).
> > > endif
> > >
> > > CONFIG_$(XEN_OS) := y
> > > --- a/tools/Rules.mk Sat May 05 13:48:05 2007 +0100
> > > +++ b/tools/Rules.mk Thu May 31 21:04:53 2007 +0300
> > > @@ -13,6 +13,14 @@ X11_LDPATH = -L/usr/X11R6/$(LIBDIR)
> > X11_LDPATH =
> > > -L/usr/X11R6/$(LIBDIR)
> > >
> > > CFLAGS += -D__XEN_TOOLS__
> > > +
> > > +ifeq ($(passthrough),y)
> > > + CFLAGS += -DCONFIG_NEO
> > > +endif
> >
> > You probably want a better name than CONFIG_NEO, much to the
> > disappointment of matrix fans everywhere.
>
> Hehe :)
> It'll be removed completely.
> The 1:1 enabled layout will be controlled by a boot parameter.
Ok, good.
Cheers,
Muli
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