Re: [Qemu-devel] [PATCH 2/5] ppc: Split pcr_mask settings into supported bits and the register mask

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Thomas Huth (2016-06-07 10:39:37)
> The current pcr_mask values are ambiguous: Should these be the mask
> that defines valid bits in the PCR register? Or should these rather
> indicate which compatibility levels are possible? Anyway, POWER6 and
> POWER7 should certainly not use the same values here. So let's
> introduce an additional variable "pcr_supported" here which is
> used to indicate the valid compatibility levels, and use pcr_mask
> to signal the valid bits in the PCR register.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  hw/ppc/spapr_hcall.c        | 4 ++--
>  target-ppc/cpu-qom.h        | 3 ++-
>  target-ppc/cpu.h            | 1 +
>  target-ppc/translate_init.c | 6 ++++--
>  4 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index bb8f4de..cc16249 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -934,9 +934,9 @@ static void cas_handle_compat_cpu(PowerPCCPUClass *pcc, uint32_t pvr,
>      }
> 
>      /* If it is a logical PVR, try to determine the highest level */
> -    is205 = (pcc->pcr_mask & PCR_COMPAT_2_05) &&
> +    is205 = (pcc->pcr_supported & PCR_COMPAT_2_05) &&
>              (lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_05));
> -    is206 = (pcc->pcr_mask & PCR_COMPAT_2_06) &&
> +    is206 = (pcc->pcr_supported & PCR_COMPAT_2_06) &&
>              ((lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_06)) ||
>               (lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_06_PLUS)));
> 
> diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
> index 07358aa..969ecdf 100644
> --- a/target-ppc/cpu-qom.h
> +++ b/target-ppc/cpu-qom.h
> @@ -165,7 +165,8 @@ typedef struct PowerPCCPUClass {
> 
>      uint32_t pvr;
>      bool (*pvr_match)(struct PowerPCCPUClass *pcc, uint32_t pvr);
> -    uint64_t pcr_mask;
> +    uint64_t pcr_mask;          /* Available bits in PCR register */
> +    uint64_t pcr_supported;     /* Bits for supported PowerISA versions */
>      uint32_t svr;
>      uint64_t insns_flags;
>      uint64_t insns_flags2;
> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
> index c2962d7..c00a3b5 100644
> --- a/target-ppc/cpu.h
> +++ b/target-ppc/cpu.h
> @@ -2202,6 +2202,7 @@ enum {
>  enum {
>      PCR_COMPAT_2_05     = 1ull << (63-62),
>      PCR_COMPAT_2_06     = 1ull << (63-61),
> +    PCR_COMPAT_2_07     = 1ull << (63-60),

This gets introduced somewhat subtly here, maybe move it to patch 5?

>      PCR_VEC_DIS         = 1ull << (63-0), /* Vec. disable (bit NA since POWER8) */
>      PCR_VSX_DIS         = 1ull << (63-1), /* VSX disable (bit NA since POWER8) */
>      PCR_TM_DIS          = 1ull << (63-2), /* Trans. memory disable (POWER8) */
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index a1db500..fa09183 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8365,7 +8365,8 @@ POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
>      dc->desc = "POWER7";
>      dc->props = powerpc_servercpu_properties;
>      pcc->pvr_match = ppc_pvr_match_power7;
> -    pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
> +    pcc->pcr_mask = PCR_VEC_DIS | PCR_VSX_DIS | PCR_COMPAT_2_05;
> +    pcc->pcr_supported = PCR_COMPAT_2_06 | PCR_COMPAT_2_05;
>      pcc->init_proc = init_proc_POWER7;
>      pcc->check_pow = check_pow_nocheck;
>      pcc->insns_flags = PPC_INSNS_BASE | PPC_ISEL | PPC_STRING | PPC_MFTB |
> @@ -8445,7 +8446,8 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
>      dc->desc = "POWER8";
>      dc->props = powerpc_servercpu_properties;
>      pcc->pvr_match = ppc_pvr_match_power8;
> -    pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
> +    pcc->pcr_mask = PCR_TM_DIS | PCR_COMPAT_2_06 | PCR_COMPAT_2_05;
> +    pcc->pcr_supported = PCR_COMPAT_2_07 | PCR_COMPAT_2_06 | PCR_COMPAT_2_05;
>      pcc->init_proc = init_proc_POWER8;
>      pcc->check_pow = check_pow_nocheck;
>      pcc->insns_flags = PPC_INSNS_BASE | PPC_ISEL | PPC_STRING | PPC_MFTB |
> -- 
> 1.8.3.1
> 
>