Re: [Qemu-devel] [Qemu-ppc] [PULL 04/12] ppc: tlbie, tlbia and tlbisync are HV only

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

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On Wed, Jun 01, 2016 at 08:03:08AM +0100, Mark Cave-Ayland wrote:
> On 01/06/16 03:15, David Gibson wrote:
> 
> > On Tue, May 31, 2016 at 11:28:49PM +0100, Mark Cave-Ayland wrote:
> >> On 31/05/16 01:41, David Gibson wrote:
> >>
> >>> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> >>>
> >>> Not that anything remotely recent supports tlbia but ...
> >>>
> >>> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> >>> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> >>> ---
> >>>  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 dfd3010..690ffd2 100644
> >>> --- a/target-ppc/translate.c
> >>> +++ b/target-ppc/translate.c
> >>> @@ -4858,7 +4858,7 @@ static void gen_tlbie(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;
> >>>      }
> >>> @@ -4879,7 +4879,7 @@ static void gen_tlbsync(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;
> >>>      }
> >>> @@ -4898,7 +4898,7 @@ static void gen_slbia(DisasContext *ctx)
> >>>  #if defined(CONFIG_USER_ONLY)
> >>>      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >>>  #else
> >>> -    if (unlikely(ctx->pr)) {
> >>> +    if (unlikely(ctx->pr || !ctx->hv)) {
> >>>          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
> >>>          return;
> >>>      }
> >>
> >> Unfortunately this patch breaks qemu-system-ppc for both g3beige and
> >> mac99 under TCG causing a freeze in OpenBIOS when starting
> >> qemu-system-ppc with no parameters.
> > 
> > Bother, sorry.
> > 
> > I think this is because I applied this without the patch that treats
> > machines with no hypervisor mode (e.g. Apples) as always being in
> > hypervisor mode.
> 
> No problem, I can cope for a couple of days or so.

Cédric,

Not sure if you've seen this thread, but one of the HV-mode patches
caused a regression on Mac.  I think it's because I didn't include the
other patch which treats Apple-mode PPCs as always having HV=1.

Can you make sending your updated version of that patch a priority,
even if the rest of the batch of HV patches isn't ready yet.

> >> Note that there is also another regression that has recently landed in
> >> git master so you'll also need to revert
> >> e7c9136977cb99c6eb52c9139f7b8d8b5fa87db9 in order to get back to a
> >> functioning OpenBIOS.
> > 
> > I'd preter to see it fixed rather than just reverted..
> 
> Looks like the original author has found the bug, so there should be a
> fix coming up for this soon (I only included it here in case you needed
> an explicit test case).

Ok.

So, yeah, I'm not really set up to test Mac machines which means I
don't easily catch regressions like this.

Mark,

Could you look into adding a testcase to "make check" that will at
least catch these unsubtle breaks boot type regressions?

-- 
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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