Re: [Xen-devel] [PATCH] xen/arm: remove special dom0 case in dump_hyp_walk

[Stefano Stabellini <sstabellini@kernel.org>]

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On Tue, 15 Oct 2019, Jürgen Groß wrote:
> On 15.10.19 05:49, Stefano Stabellini wrote:
> > There is no need to have a special dom0 case to convert the pgtable
> > virtual address into a physical address. The virt_to_maddr function can
> > work both in the dom0 case and the domU case.
> > 
> > This is more than a cleanup: when Xen is loaded at addresses lower than
> > 2MB on arm32 phys_offset might not hold the right value and be unable to
> > perform a virt to phys conversion properly. Reducing the unnecessary
> > usage of phys_offset is a good idea.
> > 
> > Link: https://marc.info/?l=xen-devel&m=157081398022401
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
> > 
> > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> > index a6637ce347..b7883cfbab 100644
> > --- a/xen/arch/arm/mm.c
> > +++ b/xen/arch/arm/mm.c
> > @@ -284,10 +284,7 @@ void dump_hyp_walk(vaddr_t addr)
> >              "on CPU%d via TTBR 0x%016"PRIx64"\n",
> >              addr, smp_processor_id(), ttbr);
> >   -    if ( smp_processor_id() == 0 )
> > -        BUG_ON( (lpae_t *)(unsigned long)(ttbr - phys_offset) != pgtable );
> > -    else
> > -        BUG_ON( virt_to_maddr(pgtable) != ttbr );
> > +    BUG_ON( virt_to_maddr(pgtable) != ttbr );
> >       dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1);
> >   }
> 
> I can't make a connection between commit message ("special dom0 case")
> and the code modification. The special case removed is about cpu 0, not
> dom0.

That's what happen when I write a commit message late in the night.
Sorry about that. I'll resend it.

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