Re: [PATCH] powerpc/mm/radix: GR field got removed in ISA 3.0B

[Paul Mackerras <paulus@ozlabs.org>]

On Wed, Jun 21, 2017 at 10:50:12AM +0530, Aneesh Kumar K.V wrote:
> The bit position is now marked reserved. Hence don't set the bit to 1.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/mmu.h | 1 -
>  arch/powerpc/kvm/book3s_hv.c             | 6 +-----
>  arch/powerpc/mm/pgtable-radix.c          | 2 +-
>  3 files changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
> index 77529a3e3811..e28ce2793e7d 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
> @@ -55,7 +55,6 @@ extern struct patb_entry *partition_tb;
>  #define RPDS_MASK	0x1f		/* root page dir. size field */
>  
>  /* Bits in patb1 field */
> -#define PATB_GR		(1UL << 63)	/* guest uses radix; must match HR */
>  #define PRTS_MASK	0x1f		/* process table size field */
>  #define PRTB_MASK	0x0ffffffffffff000UL
>  
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 42b7a4fd57d9..657729a433f9 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -3185,7 +3185,7 @@ static void kvmppc_setup_partition_table(struct kvm *kvm)
>  	} else {
>  		dw0 = PATB_HR | radix__get_tree_size() |
>  			__pa(kvm->arch.pgtable) | RADIX_PGD_INDEX_SIZE;
> -		dw1 = PATB_GR | kvm->arch.process_table;
> +		dw1 = kvm->arch.process_table;
>  	}
>  
>  	mmu_partition_table_set_entry(kvm->arch.lpid, dw0, dw1);
> @@ -3840,10 +3840,6 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
>  	if (radix != kvm_is_radix(kvm))
>  		return -EINVAL;
>  
> -	/* GR (guest radix) bit in process_table field must match */
> -	if (!!(cfg->process_table & PATB_GR) != radix)
> -		return -EINVAL;
> -

It's OK to take out the check, but we should also clear the GR bit,
and preferably any other reserved bits, before we put the value into
the partition table.

Paul.