Re: [PATCH v4 5/8] KVM: PPC: Ultravisor: Restrict flush of the partition tlb cache

[janani <janani@linux.ibm.com>]

On 2019-06-28 15:08, Claudio Carvalho wrote:
> From: Ram Pai <linuxram@us.ibm.com>
> 
> Ultravisor is responsible for flushing the tlb cache, since it manages
> the PATE entries. Hence skip tlb flush, if the ultravisor firmware is
> available.
> 
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
> ---
>  arch/powerpc/mm/book3s64/pgtable.c | 33 +++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/powerpc/mm/book3s64/pgtable.c
> b/arch/powerpc/mm/book3s64/pgtable.c
> index 224c5c7c2e3d..bc8eb2bf9810 100644
> --- a/arch/powerpc/mm/book3s64/pgtable.c
> +++ b/arch/powerpc/mm/book3s64/pgtable.c
> @@ -224,6 +224,23 @@ void __init mmu_partition_table_init(void)
>  	powernv_set_nmmu_ptcr(ptcr);
>  }
> 
> +static void flush_partition(unsigned int lpid, unsigned long dw0)
> +{
> +	if (dw0 & PATB_HR) {
> +		asm volatile(PPC_TLBIE_5(%0, %1, 2, 0, 1) : :
> +			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> +		asm volatile(PPC_TLBIE_5(%0, %1, 2, 1, 1) : :
> +			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> +		trace_tlbie(lpid, 0, TLBIEL_INVAL_SET_LPID, lpid, 2, 0, 1);
> +	} else {
> +		asm volatile(PPC_TLBIE_5(%0, %1, 2, 0, 0) : :
> +			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> +		trace_tlbie(lpid, 0, TLBIEL_INVAL_SET_LPID, lpid, 2, 0, 0);
> +	}
> +	/* do we need fixup here ?*/
> +	asm volatile("eieio; tlbsync; ptesync" : : : "memory");
> +}
> +
>  static void __mmu_partition_table_set_entry(unsigned int lpid,
>  					    unsigned long dw0,
>  					    unsigned long dw1)
> @@ -238,20 +255,8 @@ static void
> __mmu_partition_table_set_entry(unsigned int lpid,
>  	 * The type of flush (hash or radix) depends on what the previous
>  	 * use of this partition ID was, not the new use.
>  	 */
> -	asm volatile("ptesync" : : : "memory");
  Doesn't the line above that was deleted need to be added to the 
beginning of flush_partition()
> -	if (old & PATB_HR) {
> -		asm volatile(PPC_TLBIE_5(%0,%1,2,0,1) : :
> -			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> -		asm volatile(PPC_TLBIE_5(%0,%1,2,1,1) : :
> -			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> -		trace_tlbie(lpid, 0, TLBIEL_INVAL_SET_LPID, lpid, 2, 0, 1);
> -	} else {
> -		asm volatile(PPC_TLBIE_5(%0,%1,2,0,0) : :
> -			     "r" (TLBIEL_INVAL_SET_LPID), "r" (lpid));
> -		trace_tlbie(lpid, 0, TLBIEL_INVAL_SET_LPID, lpid, 2, 0, 0);
> -	}
> -	/* do we need fixup here ?*/
> -	asm volatile("eieio; tlbsync; ptesync" : : : "memory");
> +	if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
> +		flush_partition(lpid, old);
>  }
> 
>  void mmu_partition_table_set_entry(unsigned int lpid, unsigned long 
> dw0,