From: Jan Beulich <jbeulich@suse.com>
Date: Wed, 14 Aug 2013 09:20:26 +0000 (+0200)
Subject: x86/MTRR: fix range check in mtrr_add_page()
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~6532
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=f67af6d5803b6a015e30cb490a94f9547cb0437c;p=xen.git

x86/MTRR: fix range check in mtrr_add_page()

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

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>
---

diff --git a/xen/arch/x86/cpu/mtrr/main.c b/xen/arch/x86/cpu/mtrr/main.c
index a201d72b6d..f7fc0a6e4b 100644
--- 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, unsigned long size,
 		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;
 	}