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

[David Gibson]

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 <address@hidden>

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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