Re: [Xen-devel] [RESEND][PATCH for-4.13] xen/arm: mm: Clear boot pagetables before bringing-up each secondary CPU

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

I actually forgot to CC Juergen. No wonder why I had no answer :(.

Cheers,

On 10/10/19 3:51 PM, Julien Grall wrote:
> +Juergen
>
> On 03/10/2019 02:22, Stefano Stabellini wrote:
> > On Sat, 21 Sep 2019, Julien Grall wrote:
> > > At the moment, boot pagetables are only cleared once at boot. This means
> > > when booting CPU2 (and onwards) then boot pagetables will not be
> > > cleared.
> > >
> > > To keep the interface exactly the same for all secondary CPU, the boot
> > > pagetables are now cleared before bringing-up each secondary CPU.
> > >
> > > Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> > Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> >
> >
> > > ---
> > >   xen/arch/arm/mm.c | 27 ++++++++++++++++++---------
> > >   1 file changed, 18 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> > > index 1129dc28c8..e14ee76ff8 100644
> > > --- a/xen/arch/arm/mm.c
> > > +++ b/xen/arch/arm/mm.c
> > > @@ -704,8 +704,20 @@ void __init setup_pagetables(unsigned long 
> > > boot_phys_offset)
> > >       switch_ttbr(ttbr);
> > > -    /* Clear the copy of the boot pagetables. Each secondary CPU
> > > -     * rebuilds these itself (see head.S) */
> > > +    xen_pt_enforce_wnx();
> > > +
> > > +#ifdef CONFIG_ARM_32
> > > +    per_cpu(xen_pgtable, 0) = cpu0_pgtable;
> > > +    per_cpu(xen_dommap, 0) = cpu0_dommap;
> > > +#endif
> > > +}
> > > +
> > > +static void clear_boot_pagetables(void)
> > > +{
> > > +    /*
> > > +     * Clear the copy of the boot pagetables. Each secondary CPU
> > > +     * rebuilds these itself (see head.S)
> > > +     */
> > >       clear_table(boot_pgtable);
> > >   #ifdef CONFIG_ARM_64
> > >       clear_table(boot_first);
> > > @@ -713,18 +725,13 @@ void __init setup_pagetables(unsigned long 
> > > boot_phys_offset)
> > >   #endif
> > >       clear_table(boot_second);
> > >       clear_table(boot_third);
> > > -
> > > -    xen_pt_enforce_wnx();
> > > -
> > > -#ifdef CONFIG_ARM_32
> > > -    per_cpu(xen_pgtable, 0) = cpu0_pgtable;
> > > -    per_cpu(xen_dommap, 0) = cpu0_dommap;
> > > -#endif
> > >   }
> > >   #ifdef CONFIG_ARM_64
> > >   int init_secondary_pagetables(int cpu)
> > >   {
> > > +    clear_boot_pagetables();
> > > +
> > >       /* Set init_ttbr for this CPU coming up. All CPus share a 
> > > single setof
> > >        * pagetables, but rewrite it each time for consistency with 32 
> > > bit. */
> > >       init_ttbr = (uintptr_t) xen_pgtable + phys_offset;
> > > @@ -767,6 +774,8 @@ int init_secondary_pagetables(int cpu)
> > >       per_cpu(xen_pgtable, cpu) = first;
> > >       per_cpu(xen_dommap, cpu) = domheap;
> > > +    clear_boot_pagetables();
> > > +
> > >       /* Set init_ttbr for this CPU coming up */
> > >       init_ttbr = __pa(first);
> > >       clean_dcache(init_ttbr);
> > > --
> > > 2.11.0
--
Julien Grall

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