Re: [Xen-devel] [PATCH] xen: arm: context switch the aux memory attribute registers

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 12/20/2013 03:08 PM, Ian Campbell wrote:
> We appear to have somehow missed these. Linux doesn't actually use them and
> none of the processors I've looked at actually define any bits in them (so
> they are UNK/SBZP) but it is good form to context switch them anyway.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>

> ---
>   xen/arch/arm/domain.c        |    6 ++++++
>   xen/include/asm-arm/cpregs.h |    2 ++
>   xen/include/asm-arm/domain.h |    2 ++
>   3 files changed, 10 insertions(+)
>
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 4099e88..124cccf 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -98,8 +98,11 @@ static void ctxt_switch_from(struct vcpu *p)
>   #if defined(CONFIG_ARM_32)
>       p->arch.mair0 = READ_CP32(MAIR0);
>       p->arch.mair1 = READ_CP32(MAIR1);
> +    p->arch.amair0 = READ_CP32(AMAIR0);
> +    p->arch.amair1 = READ_CP32(AMAIR1);
>   #else
>       p->arch.mair = READ_SYSREG64(MAIR_EL1);
> +    p->arch.amair = READ_SYSREG64(AMAIR_EL1);
>   #endif
>
>       /* Fault Status */
> @@ -177,8 +180,11 @@ static void ctxt_switch_to(struct vcpu *n)
>   #if defined(CONFIG_ARM_32)
>       WRITE_CP32(n->arch.mair0, MAIR0);
>       WRITE_CP32(n->arch.mair1, MAIR1);
> +    WRITE_CP32(n->arch.amair0, AMAIR0);
> +    WRITE_CP32(n->arch.amair1, AMAIR1);
>   #elif defined(CONFIG_ARM_64)
>       WRITE_SYSREG64(n->arch.mair, MAIR_EL1);
> +    WRITE_SYSREG64(n->arch.amair, AMAIR_EL1);
>   #endif
>       isb();
>
> diff --git a/xen/include/asm-arm/cpregs.h b/xen/include/asm-arm/cpregs.h
> index 29cd9d7..dcdbe47 100644
> --- a/xen/include/asm-arm/cpregs.h
> +++ b/xen/include/asm-arm/cpregs.h
> @@ -200,6 +200,8 @@
>   #define MAIR1           p15,0,c10,c2,1  /* Memory Attribute Indirection 
> Register 1 AKA NMRR */
>   #define HMAIR0          p15,4,c10,c2,0  /* Hyp. Memory Attribute Indirection 
> Register 0 */
>   #define HMAIR1          p15,4,c10,c2,1  /* Hyp. Memory Attribute Indirection 
> Register 1 */
> +#define AMAIR0          p15,0,c10,c3,0  /* Aux. Memory Attribute Indirection 
> Register 0 */
> +#define AMAIR1          p15,0,c10,c3,1  /* Aux. Memory Attribute Indirection 
> Register 1 */
>
>   /* CP15 CR11: DMA Operations for TCM Access */
>
> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> index e2202a6..bc20a15 100644
> --- a/xen/include/asm-arm/domain.h
> +++ b/xen/include/asm-arm/domain.h
> @@ -221,8 +221,10 @@ struct arch_vcpu
>       uint64_t par;
>   #ifdef CONFIG_ARM_32
>       uint32_t mair0, mair1;
> +    uint32_t amair0, amair1;
>   #else
>       uint64_t mair;
> +    uint64_t amair;
>   #endif
>
>       /* Control Registers */
--
Julien Grall

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