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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 21-02-09 11:16:08, Robin Murphy wrote: > On 2021-02-07 09:56, Yi Sun wrote: > >Hi, > > > >On 21-01-28 23:17:41, Keqian Zhu wrote: > > > >[...] > > > >>+static void vfio_dma_dirty_log_start(struct vfio_iommu *iommu, > >>+ struct vfio_dma *dma) > >>+{ > >>+ struct vfio_domain *d; > >>+ > >>+ list_for_each_entry(d, &iommu->domain_list, next) { > >>+ /* Go through all domain anyway even if we fail */ > >>+ iommu_split_block(d->domain, dma->iova, dma->size); > >>+ } > >>+} > > > >This should be a switch to prepare for dirty log start. Per Intel > >Vtd spec, there is SLADE defined in Scalable-Mode PASID Table Entry. > >It enables Accessed/Dirty Flags in second-level paging entries. > >So, a generic iommu interface here is better. For Intel iommu, it > >enables SLADE. For ARM, it splits block. > > From a quick look, VT-D's SLADE and SMMU's HTTU appear to be the > exact same thing. This step isn't about enabling or disabling that > feature itself (the proposal for SMMU is to simply leave HTTU > enabled all the time), it's about controlling the granularity at > which the dirty status can be detected/reported at all, since that's > tied to the pagetable structure. > > However, if an IOMMU were to come along with some other way of > reporting dirty status that didn't depend on the granularity of > individual mappings, then indeed it wouldn't need this operation. > Per my thought, we can use these two start/stop interfaces to make user space decide when to start/stop the dirty tracking. For Intel SLADE, I think we can enable this bit when this start interface is called by user space. I don't think leave SLADE enabled all the time is necessary for Intel Vt-d. So I suggest a generic interface here. Thanks! > Robin. > > >>+ > >>+static void vfio_dma_dirty_log_stop(struct vfio_iommu *iommu, > >>+ struct vfio_dma *dma) > >>+{ > >>+ struct vfio_domain *d; > >>+ > >>+ list_for_each_entry(d, &iommu->domain_list, next) { > >>+ /* Go through all domain anyway even if we fail */ > >>+ iommu_merge_page(d->domain, dma->iova, dma->size, > >>+ d->prot | dma->prot); > >>+ } > >>+} > > > >Same as above comment, a generic interface is required here. > > > >>+ > >>+static void vfio_iommu_dirty_log_switch(struct vfio_iommu *iommu, bool start) > >>+{ > >>+ struct rb_node *n; > >>+ > >>+ /* Split and merge even if all iommu don't support HWDBM now */ > >>+ for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { > >>+ struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > >>+ > >>+ if (!dma->iommu_mapped) > >>+ continue; > >>+ > >>+ /* Go through all dma range anyway even if we fail */ > >>+ if (start) > >>+ vfio_dma_dirty_log_start(iommu, dma); > >>+ else > >>+ vfio_dma_dirty_log_stop(iommu, dma); > >>+ } > >>+} > >>+ > >> static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> unsigned long arg) > >> { > >>@@ -2812,8 +2900,10 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> pgsize = 1 << __ffs(iommu->pgsize_bitmap); > >> if (!iommu->dirty_page_tracking) { > >> ret = vfio_dma_bitmap_alloc_all(iommu, pgsize); > >>- if (!ret) > >>+ if (!ret) { > >> iommu->dirty_page_tracking = true; > >>+ vfio_iommu_dirty_log_switch(iommu, true); > >>+ } > >> } > >> mutex_unlock(&iommu->lock); > >> return ret; > >>@@ -2822,6 +2912,7 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> if (iommu->dirty_page_tracking) { > >> iommu->dirty_page_tracking = false; > >> vfio_dma_bitmap_free_all(iommu); > >>+ vfio_iommu_dirty_log_switch(iommu, false); > >> } > >> mutex_unlock(&iommu->lock); > >> return 0; > >>-- > >>2.19.1 > >_______________________________________________ > >iommu mailing list > >iommu@lists.linux-foundation.org > >https://lists.linuxfoundation.org/mailman/listinfo/iommu > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel