[Xen-devel] [PATCH 08/10] x86/pci: make sure _PAGE_IOMAP it set on pci mappings

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

When mapping pci space via /sys or /proc, make sure we're really
doing a hardware mapping by setting _PAGE_IOMAP.

[ Impact: bugfix; make PCI mappings map the right pages ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Reviewed-by: "H. Peter Anvin" <hpa@xxxxxxxxx>
Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
 arch/x86/pci/i386.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index a85bef2..88a1080 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -278,6 +278,9 @@ int pci_mmap_page_range(struct pci_dev *dev, struct 
vm_area_struct *vma,
                return -EINVAL;
 
        prot = pgprot_val(vma->vm_page_prot);
+
+       prot |= _PAGE_IOMAP;    /* creating a mapping for IO */
+
        if (pat_enabled && write_combine)
                prot |= _PAGE_CACHE_WC;
        else if (pat_enabled || boot_cpu_data.x86 > 3)
-- 
1.6.0.6


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