Re: [PATCH 4/6] target/ppc: 4xx optimise tlbwe_lo TLB flushing

[Cédric Le Goater]

On 1/17/24 16:12, Nicholas Piggin wrote:
> Rather than tlbwe_lo always flushing all TCG TLBs, have it flush just
> those corresponding to the old software TLB, and only if it was valid.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>



Acked-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.

> ---
>   target/ppc/mmu_helper.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
> index 68632bf54e..923779d052 100644
> --- a/target/ppc/mmu_helper.c
> +++ b/target/ppc/mmu_helper.c
> @@ -813,12 +813,20 @@ void helper_4xx_tlbwe_hi(CPUPPCState *env, target_ulong 
> entry,
>   void helper_4xx_tlbwe_lo(CPUPPCState *env, target_ulong entry,
>                            target_ulong val)
>   {
> +    CPUState *cs = env_cpu(env);
>       ppcemb_tlb_t *tlb;
>   
>       qemu_log_mask(CPU_LOG_MMU, "%s entry %i val " TARGET_FMT_lx "\n",
>                     __func__, (int)entry, val);
>       entry &= PPC4XX_TLB_ENTRY_MASK;
>       tlb = &env->tlb.tlbe[entry];
> +    /* Invalidate previous TLB (if it's valid) */
> +    if (tlb->prot & PAGE_VALID) {
> +        qemu_log_mask(CPU_LOG_MMU, "%s: invalidate old TLB %d start "
> +                      TARGET_FMT_lx " end " TARGET_FMT_lx "\n", __func__,
> +                      (int)entry, tlb->EPN, tlb->EPN + tlb->size);
> +        ppcemb_tlb_flush(cs, tlb);
> +    }
>       tlb->attr = val & PPC4XX_TLBLO_ATTR_MASK;
>       tlb->RPN = val & PPC4XX_TLBLO_RPN_MASK;
>       tlb->prot = PAGE_READ;
> @@ -836,8 +844,6 @@ void helper_4xx_tlbwe_lo(CPUPPCState *env, target_ulong 
> entry,
>                     tlb->prot & PAGE_WRITE ? 'w' : '-',
>                     tlb->prot & PAGE_EXEC ? 'x' : '-',
>                     tlb->prot & PAGE_VALID ? 'v' : '-', (int)tlb->PID);
> -
> -    env->tlb_need_flush |= TLB_NEED_LOCAL_FLUSH;
>   }
>   
>   target_ulong helper_4xx_tlbsx(CPUPPCState *env, target_ulong address)