[PATCH] KVM: PPC: e500: Fix default tlb for victim hint

[Scott Wood]

On Mon, 2014-06-30 at 15:54 +0300, Mihai Caraman wrote:
> Tlb search operation used for victim hint relies on the default tlb set by the
> host. When hardware tablewalk support is enabled in the host, the default tlb is
> TLB1 which leads KVM to evict the bolted entry. Set and restore the default tlb
> when searching for victim hint.
> 
> Signed-off-by: Mihai Caraman <mihai.caraman at freescale.com>
> ---
>  arch/powerpc/include/asm/mmu-book3e.h | 5 ++++-
>  arch/powerpc/kvm/e500_mmu_host.c      | 4 ++++
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/mmu-book3e.h b/arch/powerpc/include/asm/mmu-book3e.h
> index 901dac6..5dad378 100644
> --- a/arch/powerpc/include/asm/mmu-book3e.h
> +++ b/arch/powerpc/include/asm/mmu-book3e.h
> @@ -40,7 +40,9 @@
>  
>  /* MAS registers bit definitions */
>  
> -#define MAS0_TLBSEL(x)		(((x) << 28) & 0x30000000)
> +#define MAS0_TLBSEL_MASK        0x30000000
> +#define MAS0_TLBSEL_SHIFT       28
> +#define MAS0_TLBSEL(x)          (((x) << MAS0_TLBSEL_SHIFT) & MAS0_TLBSEL_MASK)
>  #define MAS0_ESEL_MASK		0x0FFF0000
>  #define MAS0_ESEL_SHIFT		16
>  #define MAS0_ESEL(x)		(((x) << MAS0_ESEL_SHIFT) & MAS0_ESEL_MASK)
> @@ -86,6 +88,7 @@
>  #define MAS3_SPSIZE		0x0000003e
>  #define MAS3_SPSIZE_SHIFT	1
>  
> +#define MAS4_TLBSEL_MASK	MAS0_TLBSEL_MASK
>  #define MAS4_TLBSELD(x) 	MAS0_TLBSEL(x)
>  #define MAS4_INDD		0x00008000	/* Default IND */
>  #define MAS4_TSIZED(x)		MAS1_TSIZE(x)
> diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
> index dd2cc03..79677d7 100644
> --- a/arch/powerpc/kvm/e500_mmu_host.c
> +++ b/arch/powerpc/kvm/e500_mmu_host.c
> @@ -107,11 +107,15 @@ static u32 get_host_mas0(unsigned long eaddr)
>  {
>  	unsigned long flags;
>  	u32 mas0;
> +	u32 mas4;
>  
>  	local_irq_save(flags);
>  	mtspr(SPRN_MAS6, 0);
> +	mas4 = mfspr(SPRN_MAS4);
> +	mtspr(SPRN_MAS4, mas4 & ~MAS4_TLBSEL_MASK);
>  	asm volatile("tlbsx 0, %0" : : "b" (eaddr & ~CONFIG_PAGE_OFFSET));
>  	mas0 = mfspr(SPRN_MAS0);
> +	mtspr(SPRN_MAS4, mas4);
>  	local_irq_restore(flags);
>  
>  	return mas0;

Reviewed-by: Scott Wood <scottwood at freescale.com>

-Scott