Re: [Qemu-devel] [PATCH 3/3] ppc: fix hrfid, tlbia and slbia privilege

[David Gibson <david@gibson.dropbear.id.au>]

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On Sat, Jun 04, 2016 at 10:24:28AM +0200, Thomas Huth wrote:
> On 03.06.2016 14:11, Cédric Le Goater wrote:
> > commit 74693da98894 ('ppc: tlbie, tlbia and tlbisync are HV only')
> > introduced some extra checks on the instruction privilege. slbia was
> > changed wrongly and hrfid, tlbia were forgotten.
> > 
> > Signed-off-by: Cédric Le Goater <clg@kaod.org>
> > ---
> >  target-ppc/translate.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> > index ad262523abca..776343170a53 100644
> > --- a/target-ppc/translate.c
> > +++ b/target-ppc/translate.c
> > @@ -4108,7 +4108,7 @@ static void gen_hrfid(DisasContext *ctx)
> >      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >  #else
> >      /* Restore CPU state */
> > -    if (unlikely(!ctx->hv)) {
> > +    if (unlikely(ctx->pr || !ctx->hv)) {
> >          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >          return;
> >      }
> > @@ -4845,7 +4845,7 @@ static void gen_tlbia(DisasContext *ctx)
> >  #if defined(CONFIG_USER_ONLY)
> >      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >  #else
> > -    if (unlikely(ctx->pr)) {
> > +    if (unlikely(ctx->pr || !ctx->hv)) {
> >          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >          return;
> >      }
> > @@ -4913,7 +4913,7 @@ static void gen_slbia(DisasContext *ctx)
> >  #if defined(CONFIG_USER_ONLY)
> >      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >  #else
> > -    if (unlikely(ctx->pr || !ctx->hv)) {
> > +    if (unlikely(ctx->pr)) {
> >          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >          return;
> >      }
> 
> I just double-checked the PowerISA 2.07, and you're right, hrfid and
> tlbia are hypervisor-privileged, slbia is only "normal" privileged.
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>

Yes, the SLB is owned by the guest - otherwise it would need
hypercalls on every context switch.  Should have caught this the first
time around, sorry.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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