[Xen-devel] [PATCH] x86/MTRR: fix range check in mtrr_add_page()

["Jan Beulich" <JBeulich@xxxxxxxx>]

Extracted from Yinghai Lu's Linux commit d5c78673 ("x86: Fix /proc/mtrr
with base/size more than 44bits").

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/cpu/mtrr/main.c
+++ b/xen/arch/x86/cpu/mtrr/main.c
@@ -340,7 +340,7 @@ int mtrr_add_page(unsigned long base, un
                return -EINVAL;
        }
 
-       if (base & size_or_mask || size & size_or_mask) {
+       if ((base | (base + size - 1)) >> (paddr_bits - PAGE_SHIFT)) {
                printk(KERN_WARNING "mtrr: base or size exceeds the MTRR 
width\n");
                return -EINVAL;
        }

Attachment: x86-MTRR-add-page-check.patch
Description: Text document

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