Re: [Qemu-devel] [PATCH] powerpc/mm: Update the WIMG check during H_ENTER

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

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On Fri, Jun 17, 2016 at 04:07:20PM +0530, Aneesh Kumar K.V wrote:
> Support for 0 value for memeory coherence is optional and with ppc64
> we can always enable memory coherence. Linux kernel did that during
> the development of 4.7 kernel. But that resulted in failure in Qemu
> in H_ENTER hcall due to below check. The mentioned change was reverted
> in the kernel and kernel right now enable memory coherence only if
> cache inhibited is not set. Nevertheless update qemu WIMG flag check
> to cover the case where we enable memory coherence along with cache
> inhibited flag.
> 
> In order to handle older and newer kernel version consider both Cache
> inhibitted and (cache inhibitted | memory conference) as valid values
> for wimg flags.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Applied to ppc-for-2.7

> ---
>  hw/ppc/spapr_hcall.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 2ba5cbdb194a..e011ed4b664b 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -102,11 +102,15 @@ static target_ulong h_enter(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>              return H_PARAMETER;
>          }
>      } else {
> +        target_ulong wimg_flags;
>          /* Looks like an IO address */
>          /* FIXME: What WIMG combinations could be sensible for IO?
>           * For now we allow WIMG=010x, but are there others? */
>          /* FIXME: Should we check against registered IO addresses? */
> -        if ((ptel & (HPTE64_R_W | HPTE64_R_I | HPTE64_R_M)) != HPTE64_R_I) {
> +        wimg_flags = (ptel & (HPTE64_R_W | HPTE64_R_I | HPTE64_R_M));
> +
> +        if (wimg_flags != HPTE64_R_I &&
> +            wimg_flags != (HPTE64_R_I | HPTE64_R_M)) {
>              return H_PARAMETER;
>          }
>      }

-- 
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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