iommu/dma: Avoid PCI host bridge windows
With our DMA ops enabled for PCI devices, we should avoid allocating
IOVAs which a host bridge might misinterpret as peer-to-peer DMA and
lead to faults, corruption or other badness. To be safe, punch out holes
for all of the relevant host bridge's windows when initialising a DMA
domain for a PCI device.
CC: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Inki Dae <inki.dae@samsung.com>
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4329d18..c5ab866 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -27,6 +27,7 @@
#include <linux/iova.h>
#include <linux/irq.h>
#include <linux/mm.h>
+#include <linux/pci.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
@@ -103,18 +104,38 @@
}
EXPORT_SYMBOL(iommu_put_dma_cookie);
+static void iova_reserve_pci_windows(struct pci_dev *dev,
+ struct iova_domain *iovad)
+{
+ struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+ struct resource_entry *window;
+ unsigned long lo, hi;
+
+ resource_list_for_each_entry(window, &bridge->windows) {
+ if (resource_type(window->res) != IORESOURCE_MEM &&
+ resource_type(window->res) != IORESOURCE_IO)
+ continue;
+
+ lo = iova_pfn(iovad, window->res->start - window->offset);
+ hi = iova_pfn(iovad, window->res->end - window->offset);
+ reserve_iova(iovad, lo, hi);
+ }
+}
+
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
* @base: IOVA at which the mappable address space starts
* @size: Size of IOVA space
+ * @dev: Device the domain is being initialised for
*
* @base and @size should be exact multiples of IOMMU page granularity to
* avoid rounding surprises. If necessary, we reserve the page at address 0
* to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
* any change which could make prior IOVAs invalid will fail.
*/
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size)
+int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
+ u64 size, struct device *dev)
{
struct iova_domain *iovad = cookie_iovad(domain);
unsigned long order, base_pfn, end_pfn;
@@ -152,6 +173,8 @@
iovad->dma_32bit_pfn = end_pfn;
} else {
init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
+ if (dev && dev_is_pci(dev))
+ iova_reserve_pci_windows(to_pci_dev(dev), iovad);
}
return 0;
}