Messages in this thread Patch in this message | | | From | Yong Wu (吴勇) <> | Subject | Re: [PATCH RFC] iommu/mediatek: Flush IOTLB completely only if domain has been attached | Date | Mon, 29 May 2023 08:32:08 +0000 |
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On Fri, 2023-05-26 at 16:53 +0800, Chen-Yu Tsai wrote: > > If an IOMMU domain was never attached, it lacks any linkage to the > actual IOMMU hardware. Attempting to do flush_iotlb_all() on it will > result in a NULL pointer dereference. This seems to happen after the > recent IOMMU core rework in v6.4-rc1. > > Unable to handle kernel read from unreadable memory at virtual > address 0000000000000018 > Call trace: > mtk_iommu_flush_iotlb_all+0x20/0x80 > iommu_create_device_direct_mappings.part.0+0x13c/0x230 > iommu_setup_default_domain+0x29c/0x4d0 > iommu_probe_device+0x12c/0x190 > of_iommu_configure+0x140/0x208 > of_dma_configure_id+0x19c/0x3c0 > platform_dma_configure+0x38/0x88 > really_probe+0x78/0x2c0 > > Check if the "bank" field has been filled in before actually > attempting > the IOTLB flush to avoid it. The IOTLB is also flushed when the > device > comes out of runtime suspend, so it should have a clean initial > state. > > Fixes: 08500c43d4f7 ("iommu/mediatek: Adjust the structure")
The interface "iommu_setup_default_domain" doesn't exist in v6.4-rc1.
This is a fixes for linux-next. And the Fixes tag should be:
152431e4fe7f ("iommu: Do iommu_group_create_direct_mappings() before attach")
then: Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Thanks very much.
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> > --- > > I think this is a valid fix, but I'm not very familiar with the > hardware > or the design of the driver. The ARM SMMU drivers seem to do this as > well. > > drivers/iommu/mtk_iommu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index aecc7d154f28..e93906d6e112 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -781,7 +781,8 @@ static void mtk_iommu_flush_iotlb_all(struct > iommu_domain *domain) > { > struct mtk_iommu_domain *dom = to_mtk_domain(domain); > > - mtk_iommu_tlb_flush_all(dom->bank->parent_data); > + if (dom->bank) > + mtk_iommu_tlb_flush_all(dom->bank->parent_data); > } > > static void mtk_iommu_iotlb_sync(struct iommu_domain *domain, > -- > 2.41.0.rc0.172.g3f132b7071-goog
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