From b8397a8f4ebc0b84eefd990dc08995ba2ae9015c Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 9 May 2022 11:16:08 +0100 Subject: iommu/dma: Explicitly sort PCI DMA windows Originally, creating the dma_ranges resource list in pre-sorted fashion was the simplest and most efficient way to enforce the order required by iova_reserve_pci_windows(). However since then at least one PCI host driver is now re-sorting the list for its own probe-time processing, which doesn't seem entirely unreasonable, so that basic assumption no longer holds. Make iommu-dma robust and get the sort order it needs by explicitly sorting, which means we can also save the effort at creation time and just build the list in whatever natural order the DT had. Signed-off-by: Robin Murphy Reviewed-by: Rob Herring Link: https://lore.kernel.org/r/35661036a7e4160850895f9b37f35408b6a29f2f.1652091160.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel --- drivers/iommu/dma-iommu.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 8e0ed400a439..f90251572a5d 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -414,6 +415,15 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, return 0; } +static int iommu_dma_ranges_sort(void *priv, const struct list_head *a, + const struct list_head *b) +{ + struct resource_entry *res_a = list_entry(a, typeof(*res_a), node); + struct resource_entry *res_b = list_entry(b, typeof(*res_b), node); + + return res_a->res->start > res_b->res->start; +} + static int iova_reserve_pci_windows(struct pci_dev *dev, struct iova_domain *iovad) { @@ -432,6 +442,7 @@ static int iova_reserve_pci_windows(struct pci_dev *dev, } /* Get reserved DMA windows from host bridge */ + list_sort(NULL, &bridge->dma_ranges, iommu_dma_ranges_sort); resource_list_for_each_entry(window, &bridge->dma_ranges) { end = window->res->start - window->offset; resv_iova: @@ -440,7 +451,7 @@ resv_iova: hi = iova_pfn(iovad, end); reserve_iova(iovad, lo, hi); } else if (end < start) { - /* dma_ranges list should be sorted */ + /* DMA ranges should be non-overlapping */ dev_err(&dev->dev, "Failed to reserve IOVA [%pa-%pa]\n", &start, &end); -- cgit v1.2.3