[PATCH 3/4] Intel pci: Limit dmar_init_reserved_ranges

[Mike Travis]

    dmar_init_reserved_ranges() reserves the card's MMIO ranges to
    prevent handing out a DMA map that would overlap with the MMIO range.
    The problem while the Nvidia GPU has 64bit BARs, it's capable of
    receiving > 40bit PIOs, but can't generate > 40bit DMAs.

    So when the iommu code reserves these MMIO ranges a > 40bit
    entry ends up getting in the rbtree.  On a UV test system with
    the Nvidia cards, the BARs are:

      0001:36:00.0 VGA compatible controller: nVidia Corporation GT200GL 
	  Region 0: Memory at 92000000 (32-bit, non-prefetchable) [size=16M]
	  Region 1: Memory at f8200000000 (64-bit, prefetchable) [size=256M]
	  Region 3: Memory at 90000000 (64-bit, non-prefetchable) [size=32M]

    So this 44bit MMIO address 0xf8200000000 ends up in the rbtree.  As DMA
    maps get added and deleted from the rbtree we can end up getting a cached
    entry to this 0xf8200000000 entry... this is what results in the code
    handing out the invalid DMA map of 0xf81fffff000:

	    [ 0xf8200000000-1 >> PAGE_SIZE << PAGE_SIZE ]

    The IOVA code needs to better honor the "limit_pfn" when allocating
    these maps.

Signed-off-by: Mike Travis <travis@xxxxxxx>
Reviewed-by: Mike Habeck <habeck@xxxxxxx>
---
 drivers/pci/intel-iommu.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- linux.orig/drivers/pci/intel-iommu.c
+++ linux/drivers/pci/intel-iommu.c
@@ -1323,7 +1323,8 @@ static void dmar_init_reserved_ranges(vo
 
 		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 			r = &pdev->resource[i];
-			if (!r->flags || !(r->flags & IORESOURCE_MEM))
+			if (!r->flags || !(r->flags & IORESOURCE_MEM) ||
+			    r->start > pdev->dma_mask)
 				continue;
 			iova = reserve_iova(&reserved_iova_list,
 					    IOVA_PFN(r->start),

-- 
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