Re: [Xen-devel] [PATCH 16/22] xen/arm: p2m: Move the vttbr field from arch_domain to p2m_domain

[Julien Grall <julien.grall@xxxxxxx>]

Hi Stefano,

On 27/07/16 01:57, Stefano Stabellini wrote:
> On Wed, 20 Jul 2016, Julien Grall wrote:
> > The field vttbr holds the base address of the translation table for
> > guest. Its value will depends on how the p2m has been initialized and
> > will only be used by the code code.
>                            ^ code code?
I think I wanted to say "P2M code".

Regards,

> > So move the field from arch_domain to p2m_domain. This will also ease
> > the implementation of altp2m.
> > ---
> >  xen/arch/arm/p2m.c           | 11 +++++++----
> >  xen/arch/arm/traps.c         |  2 +-
> >  xen/include/asm-arm/domain.h |  1 -
> >  xen/include/asm-arm/p2m.h    |  3 +++
> >  4 files changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> > index c407e6a..c52081a 100644
> > --- a/xen/arch/arm/p2m.c
> > +++ b/xen/arch/arm/p2m.c
> > @@ -107,10 +107,14 @@ void dump_p2m_lookup(struct domain *d, paddr_t addr)
> >
> >  static void p2m_load_VTTBR(struct domain *d)
> >  {
> > +    struct p2m_domain *p2m = &d->arch.p2m;
> > +
> >      if ( is_idle_domain(d) )
> >          return;
> > -    BUG_ON(!d->arch.vttbr);
> > -    WRITE_SYSREG64(d->arch.vttbr, VTTBR_EL2);
> > +
> > +    ASSERT(p2m->vttbr);
> > +
> > +    WRITE_SYSREG64(p2m->vttbr, VTTBR_EL2);
> >      isb(); /* Ensure update is visible */
> >  }
> >
> > @@ -1298,8 +1302,7 @@ static int p2m_alloc_table(struct domain *d)
> >
> >      p2m->root = page;
> >
> > -    d->arch.vttbr = page_to_maddr(p2m->root)
> > -        | ((uint64_t)p2m->vmid&0xff)<<48;
> > +    p2m->vttbr = page_to_maddr(p2m->root) | ((uint64_t)p2m->vmid & 0xff) << 48;
> >
> >      /*
> >       * Make sure that all TLBs corresponding to the new VMID are flushed
> > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> > index 06a8ee5..65c6fb4 100644
> > --- a/xen/arch/arm/traps.c
> > +++ b/xen/arch/arm/traps.c
> > @@ -880,7 +880,7 @@ void vcpu_show_registers(const struct vcpu *v)
> >      ctxt.ifsr32_el2 = v->arch.ifsr;
> >  #endif
> >
> > -    ctxt.vttbr_el2 = v->domain->arch.vttbr;
> > +    ctxt.vttbr_el2 = v->domain->arch.p2m.vttbr;
> >
> >      _show_registers(&v->arch.cpu_info->guest_cpu_user_regs, &ctxt, 1, v);
> >  }
> > diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> > index 4e9d8bf..9452fcd 100644
> > --- a/xen/include/asm-arm/domain.h
> > +++ b/xen/include/asm-arm/domain.h
> > @@ -48,7 +48,6 @@ struct arch_domain
> >
> >      /* Virtual MMU */
> >      struct p2m_domain p2m;
> > -    uint64_t vttbr;
> >
> >      struct hvm_domain hvm_domain;
> >      gfn_t *grant_table_gfn;
> > diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> > index ce28e8a..53c4d78 100644
> > --- a/xen/include/asm-arm/p2m.h
> > +++ b/xen/include/asm-arm/p2m.h
> > @@ -32,6 +32,9 @@ struct p2m_domain {
> >      /* Current VMID in use */
> >      uint8_t vmid;
> >
> > +    /* Current Translation Table Base Register for the p2m */
> > +    uint64_t vttbr;
> > +
> >      /*
> >       * Highest guest frame that's ever been mapped in the p2m
> >       * Only takes into account ram and foreign mapping
> > --
> > 1.9.1
--
Julien Grall

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