Messages in this thread | | | Date | Wed, 3 Oct 2012 09:43:23 -0400 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH] xen: point xen_start_info to a dummy struct for PV on HVM guests |
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On Wed, Oct 03, 2012 at 02:37:53PM +0100, Stefano Stabellini wrote: > PV on HVM guests don't have a start_info page mapped by Xen, so > xen_start_info is just NULL for them. > That is problem because other parts of the code expect xen_start_info to > point to something valid, for example xen_initial_domain() is defined as > follow: > > #define xen_initial_domain() (xen_domain() && \ > xen_start_info->flags & SIF_INITDOMAIN) >
.. introduced by commit 4c071ee5268f7234c3d084b6093bebccc28cdcba ("arm: initial Xen support)
> > Allocate a dummy start_info struct and point xen_start_info to it, as we > do on ARM. > This is not going to change things for PV guests because > xen_start_info is set by arch/x86/xen/xen-head.S:startup_xen. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index bf788d3..5f242cb 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -96,7 +96,8 @@ EXPORT_SYMBOL(machine_to_phys_mapping); > unsigned long machine_to_phys_nr; > EXPORT_SYMBOL(machine_to_phys_nr); > > -struct start_info *xen_start_info; > +static struct start_info _xen_start_info;
And lets change that to 'xen_dummy_start_info' to keep in sync with the other dummy one.
And also add a commnt:
/* * Since 'xen_initial_domain' dereferences the xen_start_info we need * a dummy structure filled with zeros (for PVHVM guests which initialize * this late). For PV guests we do not have to worry about this as the first * few instructions (startup_xen) set it properly. */ > +struct start_info *xen_start_info = &_xen_start_info; > EXPORT_SYMBOL_GPL(xen_start_info); > > struct shared_info xen_dummy_shared_info;
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