Re: [PATCH 3/4] KVM: arm64: vgic-v3: Add support for ICC_SGI0R_EL1 and ICC_ASGI1R_EL1 accesses

[Christoffer Dall <christoffer.dall@arm.com>]

On Wed, Aug 08, 2018 at 02:15:00PM +0100, Marc Zyngier wrote:
> In order to generate Group0 SGIs, let's add some decoding logic to
> access_gic_sgi(), and pass the generating group accordingly.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/include/asm/sysreg.h |  2 ++
>  arch/arm64/kvm/sys_regs.c       | 41 +++++++++++++++++++++++++++++++--
>  2 files changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 98af0b37fb31..b0d2a52a71a3 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -314,6 +314,8 @@
>  #define SYS_ICC_DIR_EL1			sys_reg(3, 0, 12, 11, 1)
>  #define SYS_ICC_RPR_EL1			sys_reg(3, 0, 12, 11, 3)
>  #define SYS_ICC_SGI1R_EL1		sys_reg(3, 0, 12, 11, 5)
> +#define SYS_ICC_ASGI1R_EL1		sys_reg(3, 0, 12, 11, 6)
> +#define SYS_ICC_SGI0R_EL1		sys_reg(3, 0, 12, 11, 7)
>  #define SYS_ICC_IAR1_EL1		sys_reg(3, 0, 12, 12, 0)
>  #define SYS_ICC_EOIR1_EL1		sys_reg(3, 0, 12, 12, 1)
>  #define SYS_ICC_HPPIR1_EL1		sys_reg(3, 0, 12, 12, 2)
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index a09139b97e81..b09eac49e1ac 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -252,10 +252,43 @@ static bool access_gic_sgi(struct kvm_vcpu *vcpu,
>  			   struct sys_reg_params *p,
>  			   const struct sys_reg_desc *r)
>  {
> +	int group;
> +
>  	if (!p->is_write)
>  		return read_from_write_only(vcpu, p, r);
>  
> -	vgic_v3_dispatch_sgi(vcpu, p->regval, 1);
> +	/*
> +	 * In a system where GICD_CTLR.DS=1, a ICC_SGI0R_EL1 access generates
> +	 * Group0 SGIs only, while ICC_SGI1R_EL1 can generate either group,
> +	 * depending on the SGI configuration. ICC_ASGI1R_EL1 is effectively
> +	 * equivalent to ICC_SGI0R_EL1, as there is no "alternative" secure
> +	 * group.
> +	 */
> +	if (p->is_aarch32) {
> +		switch (p->Op1) {
> +		default:		/* Keep GCC quiet */
> +		case 0:			/* ICC_SGI1R */
> +			group = 1;
> +			break;
> +		case 1:			/* ICC_ASGI1R */
> +		case 2:			/* ICC_SGI0R */
> +			group = 0;
> +			break;
> +		}
> +	} else {
> +		switch (p->Op2) {
> +		default:		/* Keep GCC quiet */
> +		case 5:			/* ICC_SGI1R_EL1 */
> +			group = 1;
> +			break;
> +		case 6:			/* ICC_ASGI1R_EL1 */
> +		case 7:			/* ICC_SGI0R_EL1 */
> +			group = 0;
> +			break;
> +		}
> +	}
> +
> +	vgic_v3_dispatch_sgi(vcpu, p->regval, group);
>  
>  	return true;
>  }
> @@ -1312,6 +1345,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	{ SYS_DESC(SYS_ICC_DIR_EL1), read_from_write_only },
>  	{ SYS_DESC(SYS_ICC_RPR_EL1), write_to_read_only },
>  	{ SYS_DESC(SYS_ICC_SGI1R_EL1), access_gic_sgi },
> +	{ SYS_DESC(SYS_ICC_ASGI1R_EL1), access_gic_sgi },
> +	{ SYS_DESC(SYS_ICC_SGI0R_EL1), access_gic_sgi },
>  	{ SYS_DESC(SYS_ICC_IAR1_EL1), write_to_read_only },
>  	{ SYS_DESC(SYS_ICC_EOIR1_EL1), read_from_write_only },
>  	{ SYS_DESC(SYS_ICC_HPPIR1_EL1), write_to_read_only },
> @@ -1744,8 +1779,10 @@ static const struct sys_reg_desc cp15_regs[] = {
>  static const struct sys_reg_desc cp15_64_regs[] = {
>  	{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
>  	{ Op1( 0), CRn( 0), CRm( 9), Op2( 0), access_pmu_evcntr },
> -	{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi },
> +	{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI1R */
>  	{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR1 },
> +	{ Op1( 1), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_ASGI1R */
> +	{ Op1( 2), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI0R */
>  	{ Op1( 2), CRn( 0), CRm(14), Op2( 0), access_cntp_cval },
>  };
>  
> -- 
> 2.18.0
> 

Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>