Messages in this thread | | | Date | Wed, 23 Oct 2019 17:55:44 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v4 3/7] iommu/mediatek: Use gather to achieve the tlb range flush |
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On Wed, Oct 16, 2019 at 11:33:08AM +0800, Yong Wu wrote: > Use the iommu_gather mechanism to achieve the tlb range flush. > Gather the iova range in the "tlb_add_page", then flush the merged iova > range in iotlb_sync. > > Suggested-by: Tomasz Figa <tfiga@chromium.org> > Signed-off-by: Yong Wu <yong.wu@mediatek.com> > --- > drivers/iommu/mtk_iommu.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index c2f6c78..81ac95f 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -245,11 +245,9 @@ static void mtk_iommu_tlb_flush_page_nosync(struct iommu_iotlb_gather *gather, > void *cookie) > { > struct mtk_iommu_data *data = cookie; > - unsigned long flags; > + struct iommu_domain *domain = &data->m4u_dom->domain; > > - spin_lock_irqsave(&data->tlb_lock, flags); > - mtk_iommu_tlb_add_flush_nosync(iova, granule, granule, true, cookie); > - spin_unlock_irqrestore(&data->tlb_lock, flags); > + iommu_iotlb_gather_add_page(domain, gather, iova, granule);
You need to be careful here, because iommu_iotlb_gather_add_page() can call iommu_tlb_sync() in some situations and you don't hold the lock.
> static const struct iommu_flush_ops mtk_iommu_flush_ops = { > @@ -469,9 +467,15 @@ static void mtk_iommu_iotlb_sync(struct iommu_domain *domain, > struct iommu_iotlb_gather *gather) > { > struct mtk_iommu_data *data = mtk_iommu_get_m4u_data(); > + size_t length = gather->end - gather->start; > unsigned long flags; > > + if (gather->start == ULONG_MAX) > + return; > + > spin_lock_irqsave(&data->tlb_lock, flags); > + mtk_iommu_tlb_add_flush_nosync(gather->start, length, gather->pgsize, > + false, data); > mtk_iommu_tlb_sync(data); > spin_unlock_irqrestore(&data->tlb_lock, flags);
Modulo my comment above, this fixes my previous comment. Given that mainline is already broken, I guess the runtime bisectability isn't a problem.
Will
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