Re: [PATCH RFC 02/12] x86/np2m: add np2m_flush_eptp()

[Sergey Dyasli <sergey.dyasli@citrix.com>]

On Tue, 2017-08-01 at 09:55 +0200, Egger, Christoph wrote:
> On 18.07.17 12:34, Sergey Dyasli wrote:
> > The new function finds all np2m objects with the specified eptp and
> > flushes them. p2m_flush_table_locked() is added in order not to release
> > the p2m lock after np2m_base check.
> > 
> > Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
> > ---
> >  xen/arch/x86/mm/p2m.c     | 34 +++++++++++++++++++++++++++++++---
> >  xen/include/asm-x86/p2m.h |  2 ++
> >  2 files changed, 33 insertions(+), 3 deletions(-)
> > 
> > diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> > index b8c8bba421..bc330d8f52 100644
> > --- a/xen/arch/x86/mm/p2m.c
> > +++ b/xen/arch/x86/mm/p2m.c
> > @@ -1708,15 +1708,14 @@ p2m_getlru_nestedp2m(struct domain *d, struct p2m_domain *p2m)
> >      return p2m;
> >  }
> >  
> > -/* Reset this p2m table to be empty */
> >  static void
> > -p2m_flush_table(struct p2m_domain *p2m)
> > +p2m_flush_table_locked(struct p2m_domain *p2m)
> >  {
> >      struct page_info *top, *pg;
> >      struct domain *d = p2m->domain;
> >      mfn_t mfn;
> >  
> > -    p2m_lock(p2m);
> > +    ASSERT(p2m_locked_by_me(p2m));
> >  
> >      /*
> >       * "Host" p2m tables can have shared entries &c that need a bit more care
> > @@ -1756,6 +1755,14 @@ p2m_flush_table(struct p2m_domain *p2m)
> >      p2m_unlock(p2m);
> >  }
> >  
> > +/* Reset this p2m table to be empty */
> > +static void
> > +p2m_flush_table(struct p2m_domain *p2m)
> > +{
> > +    p2m_lock(p2m);
> > +    p2m_flush_table_locked(p2m);
> > +}
> > +
> >  void
> >  p2m_flush(struct vcpu *v, struct p2m_domain *p2m)
> >  {
> > @@ -1773,6 +1780,27 @@ p2m_flush_nestedp2m(struct domain *d)
> >          p2m_flush_table(d->arch.nested_p2m[i]);
> >  }
> >  
> > +void np2m_flush_eptp(struct vcpu *v, unsigned long eptp)
> > +{
> > +    struct domain *d = v->domain;
> > +    struct p2m_domain *p2m;
> > +    unsigned int i;
> > +
> > +    eptp &= ~(0xfffull);
> > +
> > +    nestedp2m_lock(d);
> > +    for ( i = 0; i < MAX_NESTEDP2M; i++ )
> > +    {
> > +        p2m = d->arch.nested_p2m[i];
> > +        p2m_lock(p2m);
> > +        if ( p2m->np2m_base == eptp )
> > +            p2m_flush_table_locked(p2m);
> > +        else
> > +            p2m_unlock(p2m);
> > +    }
> > +    nestedp2m_unlock(d);
> > +}
> > +
> 
> What exactly is eptp specific in this function ?

Yes, good point. I seem to be too focused on Intel. The correct parameter
name should be np2m_base, of course.

> >  static void assign_np2m(struct vcpu *v, struct p2m_domain *p2m)
> >  {
> >      struct nestedvcpu *nv = &vcpu_nestedhvm(v);
> > diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
> > index 9086bb35dc..0e39999387 100644
> > --- a/xen/include/asm-x86/p2m.h
> > +++ b/xen/include/asm-x86/p2m.h
> > @@ -779,6 +779,8 @@ int p2m_pt_handle_deferred_changes(uint64_t gpa);
> >  void p2m_flush(struct vcpu *v, struct p2m_domain *p2m);
> >  /* Flushes all nested p2m tables */
> >  void p2m_flush_nestedp2m(struct domain *d);
> > +/* Flushes all np2m objects with the specified eptp */
> > +void np2m_flush_eptp(struct vcpu *v, unsigned long eptp);
> >  
> >  void nestedp2m_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
> >      l1_pgentry_t *p, l1_pgentry_t new, unsigned int level);
> > 
> 
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-- 
Thanks,
Sergey
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