Re: [Xen-devel] [PATCH 05/10] xen: arm: define a macro to get this CPUs page table root

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2013-06-20 at 17:30 +0100, Stefano Stabellini wrote:
> On Tue, 18 Jun 2013, Ian Campbell wrote:
> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> Honestly I don't see this as a great improvement

In a later patch the 32 and 64 bit versions will start to differ,
because 64-bit page tables are no longer per-PCPU.

I suppose I could retain the per-cpu var and just initialise it the same
on all processors, seems a bit unnecessary though.

> 
> 
> >  xen/arch/arm/mm.c |    5 +++--
> >  1 files changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> > index 0698c75..773fbf6 100644
> > --- a/xen/arch/arm/mm.c
> > +++ b/xen/arch/arm/mm.c
> > @@ -60,6 +60,7 @@ lpae_t boot_first[LPAE_ENTRIES] 
> > __attribute__((__aligned__(4096)));
> >  /* Per-CPU pagetable pages */
> >  /* xen_pgtable == root of the trie (zeroeth level on 64-bit, first on 
> > 32-bit) */
> >  static DEFINE_PER_CPU(lpae_t *, xen_pgtable);
> > +#define THIS_CPU_PGTABLE this_cpu(xen_pgtable)
> >  /* xen_dommap == pages used by map_domain_page, these pages contain
> >   * the second level pagetables which mapp the domheap region
> >   * DOMHEAP_VIRT_START...DOMHEAP_VIRT_END in 2MB chunks. */
> > @@ -147,7 +148,7 @@ done:
> >  void dump_hyp_walk(vaddr_t addr)
> >  {
> >      uint64_t ttbr = READ_SYSREG64(TTBR0_EL2);
> > -    lpae_t *pgtable = this_cpu(xen_pgtable);
> > +    lpae_t *pgtable = THIS_CPU_PGTABLE;
> >  
> >      printk("Walking Hypervisor VA 0x%"PRIvaddr" "
> >             "on CPU%d via TTBR 0x%016"PRIx64"\n",
> > @@ -502,7 +503,7 @@ void __cpuinit mmu_init_secondary_cpu(void)
> >      uint64_t ttbr;
> >  
> >      /* Change to this CPU's pagetables */
> > -    ttbr = (uintptr_t)virt_to_maddr(this_cpu(xen_pgtable));
> > +    ttbr = (uintptr_t)virt_to_maddr(THIS_CPU_PGTABLE);
> >      WRITE_TTBR(ttbr);
> >  
> >      /* From now on, no mapping may be both writable and executable. */
> > -- 
> > 1.7.2.5
> > 



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