Re: [PATCH 19/20] PVH xen: elf and iommu related changes to prep for dom0 PVH

[Mukesh Rathor <mukesh.rathor@oracle.com>]

On Thu, 16 May 2013 09:03:16 +0100
"Jan Beulich" <JBeulich@suse.com> wrote:

> >>> On 16.05.13 at 03:58, Mukesh Rathor <mukesh.rathor@oracle.com>
> >>> wrote:
> > On Wed, 15 May 2013 13:12:56 +0100
> > "Jan Beulich" <JBeulich@suse.com> wrote:
> > 
> >> > +    {
> >> > +        unsigned long addr = (unsigned long)dst;
> >> > +        early_pvh_copy_or_zero(addr, src, filesz);
> >> > +        early_pvh_copy_or_zero(addr + filesz, NULL, memsz -
> >> > filesz);
> >> 
> >> And anyway - repeating my earlier complaint - I don't see why this
> >> is necessary. In fact I don't see why most of the PV Dom0 building
> >> code can't be used unchanged for PVH: There's no real need for
> >> lifting the few restrictions that apply, and hence there needn't be
> >> any fear of colliding address spaces.
> > 
> > Hmm... thats the best way I could come up with. If you want to
> > prototype something and replace what I've got, it's perfectly ok by
> > me.
> 
> There's nothing to prototype - just use the code that's there for
> PV Dom0.

Not sure if you are referring to just changes in elf_load_image():

+    if ( opt_dom0pvh )
+    {
+        unsigned long addr = (unsigned long)dst;
+        early_pvh_copy_or_zero(addr, src, filesz);
+        early_pvh_copy_or_zero(addr + filesz, NULL, memsz - filesz);
+
+        return 0;
+    }
+
     rc = raw_copy_to_guest(dst, src, filesz);

or all changes including construct_dom0() also?

As the comment says, for elf_load_image() we need early_pvh_copy_or_zero
because it's too early in boot and construct_dom0() is running on idle
vcpu where curr points to.

If that doesn't address your concern, please elaborate.

thanks
Mukesh