linux-kernel - Re: [PATCH 03/19] iommu/arm-smmu: Add support for split pagetables

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Message-ID: <20200901034123.GL3715@yoga>
Date:   Mon, 31 Aug 2020 22:41:23 -0500
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Rob Clark <robdclark@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, iommu@...ts.linux-foundation.org,
        linux-arm-msm@...r.kernel.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Will Deacon <will@...nel.org>, freedreno@...ts.freedesktop.org,
        Sibi Sankar <sibis@...eaurora.org>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        linux-arm-kernel@...ts.infradead.org,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Krishna Reddy <vdumpa@...dia.com>,
        Jon Hunter <jonathanh@...dia.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 03/19] iommu/arm-smmu: Add support for split pagetables

On Thu 13 Aug 21:40 CDT 2020, Rob Clark wrote:

> From: Jordan Crouse <jcrouse@...eaurora.org>
> 
> Enable TTBR1 for a context bank if IO_PGTABLE_QUIRK_ARM_TTBR1 is selected
> by the io-pgtable configuration.
> 
> Signed-off-by: Jordan Crouse <jcrouse@...eaurora.org>
> Signed-off-by: Rob Clark <robdclark@...omium.org>
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu.c | 21 ++++++++++++++++-----
>  drivers/iommu/arm/arm-smmu/arm-smmu.h | 25 +++++++++++++++++++------
>  2 files changed, 35 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index 37d8d49299b4..976d43a7f2ff 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -552,11 +552,15 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
>  			cb->ttbr[0] = pgtbl_cfg->arm_v7s_cfg.ttbr;
>  			cb->ttbr[1] = 0;
>  		} else {
> -			cb->ttbr[0] = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
> -			cb->ttbr[0] |= FIELD_PREP(ARM_SMMU_TTBRn_ASID,
> -						  cfg->asid);
> +			cb->ttbr[0] = FIELD_PREP(ARM_SMMU_TTBRn_ASID,
> +				cfg->asid);
>  			cb->ttbr[1] = FIELD_PREP(ARM_SMMU_TTBRn_ASID,
> -						 cfg->asid);
> +				cfg->asid);

The old indentation seems more appropriate.

Apart from that this looks sensible.

Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>

Regards,
Bjorn

> +
> +			if (pgtbl_cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
> +				cb->ttbr[1] |= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
> +			else
> +				cb->ttbr[0] |= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
>  		}
>  	} else {
>  		cb->ttbr[0] = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
> @@ -822,7 +826,14 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
>  
>  	/* Update the domain's page sizes to reflect the page table format */
>  	domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
> -	domain->geometry.aperture_end = (1UL << ias) - 1;
> +
> +	if (pgtbl_cfg.quirks & IO_PGTABLE_QUIRK_ARM_TTBR1) {
> +		domain->geometry.aperture_start = ~0UL << ias;
> +		domain->geometry.aperture_end = ~0UL;
> +	} else {
> +		domain->geometry.aperture_end = (1UL << ias) - 1;
> +	}
> +
>  	domain->geometry.force_aperture = true;
>  
>  	/* Initialise the context bank with our page table cfg */
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> index 83294516ac08..f3e456893f28 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> @@ -169,10 +169,12 @@ enum arm_smmu_cbar_type {
>  #define ARM_SMMU_CB_TCR			0x30
>  #define ARM_SMMU_TCR_EAE		BIT(31)
>  #define ARM_SMMU_TCR_EPD1		BIT(23)
> +#define ARM_SMMU_TCR_A1			BIT(22)
>  #define ARM_SMMU_TCR_TG0		GENMASK(15, 14)
>  #define ARM_SMMU_TCR_SH0		GENMASK(13, 12)
>  #define ARM_SMMU_TCR_ORGN0		GENMASK(11, 10)
>  #define ARM_SMMU_TCR_IRGN0		GENMASK(9, 8)
> +#define ARM_SMMU_TCR_EPD0		BIT(7)
>  #define ARM_SMMU_TCR_T0SZ		GENMASK(5, 0)
>  
>  #define ARM_SMMU_VTCR_RES1		BIT(31)
> @@ -350,12 +352,23 @@ struct arm_smmu_domain {
>  
>  static inline u32 arm_smmu_lpae_tcr(struct io_pgtable_cfg *cfg)
>  {
> -	return ARM_SMMU_TCR_EPD1 |
> -	       FIELD_PREP(ARM_SMMU_TCR_TG0, cfg->arm_lpae_s1_cfg.tcr.tg) |
> -	       FIELD_PREP(ARM_SMMU_TCR_SH0, cfg->arm_lpae_s1_cfg.tcr.sh) |
> -	       FIELD_PREP(ARM_SMMU_TCR_ORGN0, cfg->arm_lpae_s1_cfg.tcr.orgn) |
> -	       FIELD_PREP(ARM_SMMU_TCR_IRGN0, cfg->arm_lpae_s1_cfg.tcr.irgn) |
> -	       FIELD_PREP(ARM_SMMU_TCR_T0SZ, cfg->arm_lpae_s1_cfg.tcr.tsz);
> +	u32 tcr = FIELD_PREP(ARM_SMMU_TCR_TG0, cfg->arm_lpae_s1_cfg.tcr.tg) |
> +		FIELD_PREP(ARM_SMMU_TCR_SH0, cfg->arm_lpae_s1_cfg.tcr.sh) |
> +		FIELD_PREP(ARM_SMMU_TCR_ORGN0, cfg->arm_lpae_s1_cfg.tcr.orgn) |
> +		FIELD_PREP(ARM_SMMU_TCR_IRGN0, cfg->arm_lpae_s1_cfg.tcr.irgn) |
> +		FIELD_PREP(ARM_SMMU_TCR_T0SZ, cfg->arm_lpae_s1_cfg.tcr.tsz);
> +
> +       /*
> +	* When TTBR1 is selected shift the TCR fields by 16 bits and disable
> +	* translation in TTBR0
> +	*/
> +	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1) {
> +		tcr = (tcr << 16) & ~ARM_SMMU_TCR_A1;
> +		tcr |= ARM_SMMU_TCR_EPD0;
> +	} else
> +		tcr |= ARM_SMMU_TCR_EPD1;
> +
> +	return tcr;
>  }
>  
>  static inline u32 arm_smmu_lpae_tcr2(struct io_pgtable_cfg *cfg)
> -- 
> 2.26.2
>