Messages in this thread | | | Date | Fri, 4 Aug 2017 14:09:08 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH v9 05/13] iommu/amd: Add function copy_dev_tables() |
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Hi Baoquan,
On Tue, Aug 01, 2017 at 07:37:21PM +0800, Baoquan He wrote: > + for_each_iommu(iommu) { > + /* All IOMMUs should use the same device table with the same size */ > + lo = readl(iommu->mmio_base + MMIO_DEV_TABLE_OFFSET); > + hi = readl(iommu->mmio_base + MMIO_DEV_TABLE_OFFSET + 4); > + entry = (((u64) hi) << 32) + lo; > + if (last_entry && last_entry != entry) { > + pr_err("IOMMU:%d should use the same dev table as others!/n", > + iommu->index); > + return -1; > + } > + last_entry = entry; > + > + old_devtb_size = ((entry & ~PAGE_MASK) + 1) << 12; > + if (old_devtb_size != dev_table_size) { > + pr_err("The device table size of IOMMU:%d is not expected!/n", > + iommu->index); > + return -1; > + } > + > + 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?
Regards,
Joerg
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