Messages in this thread | | | Date | Fri, 4 Aug 2017 20:30:39 +0800 | From | Baoquan He <> | Subject | Re: [PATCH v9 05/13] iommu/amd: Add function copy_dev_tables() |
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On 08/04/17 at 02:09pm, Joerg Roedel wrote: > > On Tue, Aug 01, 2017 at 07:37:21PM +0800, Baoquan He wrote: > > + for_each_iommu(iommu) {
......
> > + if (copied) > > + continue; > > + > > + old_devtb_phys = entry & PAGE_MASK; > > + old_devtb = memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB); > > + if (!old_devtb) > > + return -1; > > You forgot to check whether the old device table is also below 4GB. > > > + > > + gfp_flag = GFP_KERNEL | __GFP_ZERO; > > + old_dev_tbl_cpy = (void *)__get_free_pages(gfp_flag, > > + get_order(dev_table_size)); > > + if (old_dev_tbl_cpy == NULL) { > > + pr_err("Failed to allocate memory for copying old device table!/n"); > > + return -1; > > + } > > + > > + for (devid = 0; devid <= amd_iommu_last_bdf; ++devid) { > > + old_dev_tbl_cpy[devid] = old_devtb[devid]; > > + dom_id = old_devtb[devid].data[1] & DEV_DOMID_MASK; > > + dte_v = old_devtb[devid].data[0] & DTE_FLAG_V; > > + if (dte_v && dom_id) > > + __set_bit(dom_id, amd_iommu_pd_alloc_bitmap); > > + } > > + memunmap(old_devtb); > > + copied = 1; > > And this one should be outside of the loop, then you can get rid of the > 'copied' variable. Also I don't really understand why you need a > temporary copy of the old device-table. Can't you just smart-copy the > contents of the old table to the real new one?
Sorry, I don't get 'this one' meaning, are you suggesting the copy for loop should be take out of the iommu for loop?
About the temporary copy of the old device-table, you can see in patch 7/13, if irq sanity check failed, it return -1. This return could happen in the middle of copy. So I think we should do a whole successful copy, or don't copy at all. It might not be good do half copy.
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