[Qemu-devel] [QEMU-PPC] [PATCH] ppc/tcg: Ignore bit 6 in the eieio instruction

[Qemu-devel] [QEMU-PPC] [PATCH] ppc/tcg: Ignore bit 6 in the eieio instruction

[Suraj Jitindar Singh]

The kernel patch
"powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit"
adds an eieio barrier instruction to kernel entry and exit points on
the POWER9 platform. The eieio instruction form used has bit 6 set.
This bit is ignored by hardware however under tcg it causes an illegal
instruction.

To allow these kernels to run under tcg, modify the eieio instruction
to ignore bit 6.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 target/ppc/translate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 3457d29f8e..b1ad1e2a22 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -6496,7 +6496,7 @@ GEN_HANDLER(lswi, 0x1F, 0x15, 0x12, 0x00000001, PPC_STRING),
 GEN_HANDLER(lswx, 0x1F, 0x15, 0x10, 0x00000001, PPC_STRING),
 GEN_HANDLER(stswi, 0x1F, 0x15, 0x16, 0x00000001, PPC_STRING),
 GEN_HANDLER(stswx, 0x1F, 0x15, 0x14, 0x00000001, PPC_STRING),
-GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x03FFF801, PPC_MEM_EIEIO),
+GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x01FFF801, PPC_MEM_EIEIO),
 GEN_HANDLER(isync, 0x13, 0x16, 0x04, 0x03FFF801, PPC_MEM),
 GEN_HANDLER_E(lbarx, 0x1F, 0x14, 0x01, 0, PPC_NONE, PPC2_ATOMIC_ISA206),
 GEN_HANDLER_E(lharx, 0x1F, 0x14, 0x03, 0, PPC_NONE, PPC2_ATOMIC_ISA206),
-- 
2.13.6

Re: [Qemu-devel] [QEMU-PPC] [PATCH] ppc/tcg: Ignore bit 6 in the eieio instruction

[David Gibson]

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On Fri, Jun 29, 2018 at 04:20:24PM +1000, Suraj Jitindar Singh wrote:
> The kernel patch
> "powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit"
> adds an eieio barrier instruction to kernel entry and exit points on
> the POWER9 platform. The eieio instruction form used has bit 6 set.
> This bit is ignored by hardware however under tcg it causes an illegal
> instruction.
> 
> To allow these kernels to run under tcg, modify the eieio instruction
> to ignore bit 6.
> 
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

Already done by commit c8fd8373 "target/ppc: extend eieio for POWER9".

> ---
>  target/ppc/translate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 3457d29f8e..b1ad1e2a22 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -6496,7 +6496,7 @@ GEN_HANDLER(lswi, 0x1F, 0x15, 0x12, 0x00000001, PPC_STRING),
>  GEN_HANDLER(lswx, 0x1F, 0x15, 0x10, 0x00000001, PPC_STRING),
>  GEN_HANDLER(stswi, 0x1F, 0x15, 0x16, 0x00000001, PPC_STRING),
>  GEN_HANDLER(stswx, 0x1F, 0x15, 0x14, 0x00000001, PPC_STRING),
> -GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x03FFF801, PPC_MEM_EIEIO),
> +GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x01FFF801, PPC_MEM_EIEIO),
>  GEN_HANDLER(isync, 0x13, 0x16, 0x04, 0x03FFF801, PPC_MEM),
>  GEN_HANDLER_E(lbarx, 0x1F, 0x14, 0x01, 0, PPC_NONE, PPC2_ATOMIC_ISA206),
>  GEN_HANDLER_E(lharx, 0x1F, 0x14, 0x03, 0, PPC_NONE, PPC2_ATOMIC_ISA206),

-- 
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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Re: [Qemu-devel] [QEMU-PPC] [PATCH] ppc/tcg: Ignore bit 6 in the eieio instruction

[Suraj Jitindar Singh]

On Fri, 2018-06-29 at 16:29 +1000, David Gibson wrote:
> On Fri, Jun 29, 2018 at 04:20:24PM +1000, Suraj Jitindar Singh wrote:
> > The kernel patch
> > "powerpc/64s: Add support for a store forwarding barrier at kernel
> > entry/exit"
> > adds an eieio barrier instruction to kernel entry and exit points
> > on
> > the POWER9 platform. The eieio instruction form used has bit 6 set.
> > This bit is ignored by hardware however under tcg it causes an
> > illegal
> > instruction.
> > 
> > To allow these kernels to run under tcg, modify the eieio
> > instruction
> > to ignore bit 6.
> > 
> > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> 
> Already done by commit c8fd8373 "target/ppc: extend eieio for
> POWER9".

I obviously missed that :)

> 
> > ---
> >  target/ppc/translate.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> > index 3457d29f8e..b1ad1e2a22 100644
> > --- a/target/ppc/translate.c
> > +++ b/target/ppc/translate.c
> > @@ -6496,7 +6496,7 @@ GEN_HANDLER(lswi, 0x1F, 0x15, 0x12,
> > 0x00000001, PPC_STRING),
> >  GEN_HANDLER(lswx, 0x1F, 0x15, 0x10, 0x00000001, PPC_STRING),
> >  GEN_HANDLER(stswi, 0x1F, 0x15, 0x16, 0x00000001, PPC_STRING),
> >  GEN_HANDLER(stswx, 0x1F, 0x15, 0x14, 0x00000001, PPC_STRING),
> > -GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x03FFF801, PPC_MEM_EIEIO),
> > +GEN_HANDLER(eieio, 0x1F, 0x16, 0x1A, 0x01FFF801, PPC_MEM_EIEIO),
> >  GEN_HANDLER(isync, 0x13, 0x16, 0x04, 0x03FFF801, PPC_MEM),
> >  GEN_HANDLER_E(lbarx, 0x1F, 0x14, 0x01, 0, PPC_NONE,
> > PPC2_ATOMIC_ISA206),
> >  GEN_HANDLER_E(lharx, 0x1F, 0x14, 0x03, 0, PPC_NONE,
> > PPC2_ATOMIC_ISA206),
> 
>