Re: [PATCH] iommu/mediatek: Fix share pgtable for iova over 4GB

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Yong Wu <yong.wu@mediatek.com>, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
	iommu@lists.linux.dev, linux-mediatek@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Laura Nao <laura.nao@collabora.com>
Subject: Re: [PATCH] iommu/mediatek: Fix share pgtable for iova over 4GB
Date: Thu, 7 Sep 2023 10:22:10 +0200	[thread overview]
Message-ID: <21e6631e-a99c-0b09-feb4-23407465ea55@collabora.com> (raw)
In-Reply-To: <20230819081443.8333-1-yong.wu@mediatek.com>

Il 19/08/23 10:14, Yong Wu ha scritto:
> In mt8192/mt8186, there is only one MM IOMMU that supports 16GB iova
> space, which is shared by display, vcodec and camera. These two SoC use
> one pgtable and have not the flag SHARE_PGTABLE, we should also keep
> share pgtable for this case.
> 
> In mtk_iommu_domain_finalise, MM IOMMU always share pgtable, thus remove
> the flag SHARE_PGTABLE checking. Infra IOMMU always uses independent
> pgtable.
> 
> Fixes: cf69ef46dbd9 ("iommu/mediatek: Fix two IOMMU share pagetable issue")
> Reported-by: Laura Nao <laura.nao@collabora.com>
> Closes: https://lore.kernel.org/linux-iommu/20230818154156.314742-1-laura.nao@collabora.com/
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

This is urgent. Fixes multiple machines.

> ---
> Base on next-20230818.
> ---
>   drivers/iommu/mtk_iommu.c | 9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index b17d3e7288a7..b5fcba305d2a 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -262,7 +262,7 @@ struct mtk_iommu_data {
>   	struct device			*smicomm_dev;
>   
>   	struct mtk_iommu_bank_data	*bank;
> -	struct mtk_iommu_domain		*share_dom; /* For 2 HWs share pgtable */
> +	struct mtk_iommu_domain		*share_dom;
>   
>   	struct regmap			*pericfg;
>   	struct mutex			mutex; /* Protect m4u_group/m4u_dom above */
> @@ -643,8 +643,8 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
>   	struct mtk_iommu_domain	*share_dom = data->share_dom;
>   	const struct mtk_iommu_iova_region *region;
>   
> -	/* Always use share domain in sharing pgtable case */
> -	if (MTK_IOMMU_HAS_FLAG(data->plat_data, SHARE_PGTABLE) && share_dom) {
> +	/* Share pgtable when 2 MM IOMMU share the pgtable or one IOMMU use multiple iova ranges */
> +	if (share_dom) {
>   		dom->iop = share_dom->iop;
>   		dom->cfg = share_dom->cfg;
>   		dom->domain.pgsize_bitmap = share_dom->cfg.pgsize_bitmap;
> @@ -677,8 +677,7 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
>   	/* Update our support page sizes bitmap */
>   	dom->domain.pgsize_bitmap = dom->cfg.pgsize_bitmap;
>   
> -	if (MTK_IOMMU_HAS_FLAG(data->plat_data, SHARE_PGTABLE))
> -		data->share_dom = dom;
> +	data->share_dom = dom;
>   
>   update_iova_region:
>   	/* Update the iova region for this domain */

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