Re: [Xen-devel] [PATCH for-4.10 2/2] xen/arm: p2m: Add more debug in get_page_from_gva

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 11/16/2017 01:36 AM, Stefano Stabellini wrote:
> On Wed, 15 Nov 2017, Julien Grall wrote:
> > The function get_page_from_gva is used by copy_*_guest helpers to
> > translate a guest virtual address to a machine physical address and take
> > reference on the page.
> >
> > There are a couple of errors path that will return the same value making
>                                 ^ paths
>
> > difficult to know the exact error. Add more debug in each error patch
> ^ it difficult
>
>
> > only for debug-build.
> >
> > This should help narrowing down the intermittent failure with the
> > hypercall GNTTABOP_copy (see [1]).
> >
> > [1] https://lists.xen.org/archives/html/xen-devel/2017-11/msg00942.html
> >
> > Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>
> fixed on commit
I am not sure why this was merged given Andrew gave some comments...

> > ---
> >   xen/arch/arm/p2m.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> >
> > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> > index f6b3d8e421..417609ede2 100644
> > --- a/xen/arch/arm/p2m.c
> > +++ b/xen/arch/arm/p2m.c
> > @@ -1428,16 +1428,29 @@ struct page_info *get_page_from_gva(struct vcpu *v, 
> > vaddr_t va,
> >       par = gvirt_to_maddr(va, &maddr, flags);
> >   
> >       if ( par )
> > +    {
> > +        dprintk(XENLOG_G_DEBUG,
> > +                "%pv: gvirt_to_maddr failed va=%#"PRIvaddr" flags=0x%lx 
> > par=%#"PRIx64"\n",
> > +                v, va, flags, par);
> >           goto err;
> > +    }
> >   
> >       if ( !mfn_valid(maddr_to_mfn(maddr)) )
> > +    {
> > +        dprintk(XENLOG_G_DEBUG, "%pv: Invalid MFN %#"PRI_mfn"\n",
> > +                v, mfn_x(maddr_to_mfn(maddr)));
> >           goto err;
> > +    }
> >   
> >       page = mfn_to_page(maddr_to_mfn(maddr));
> >       ASSERT(page);
> >   
> >       if ( unlikely(!get_page(page, d)) )
> > +    {
> > +        dprintk(XENLOG_G_DEBUG, "%pv: Failing to acquire the MFN 
> > %#"PRI_mfn"\n",
> > +                v, mfn_x(maddr_to_mfn(maddr)));
> >           page = NULL;
> > +    }
> >   
> >   err:
> >       if ( !page && p2m->mem_access_enabled )
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel