[4.2.y-ckt stable] Patch "KVM: MTRR: fix fixed MTRR segment look up" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    KVM: MTRR: fix fixed MTRR segment look up

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 1eef529b9641f77b0eac6cc4b6e30dd128d50a9d Mon Sep 17 00:00:00 2001
From: Alexis Dambricourt <alexis.dambricourt at gmail.com>
Date: Mon, 14 Dec 2015 15:39:34 +0100
Subject: KVM: MTRR: fix fixed MTRR segment look up

commit a7f2d7865720ff13d5b0f2a3bb1fd80dc3d7a73f upstream.

This fixes the slow-down of VM running with pci-passthrough, since some MTRR
range changed from MTRR_TYPE_WRBACK to MTRR_TYPE_UNCACHABLE.  Memory in the
0K-640K range was incorrectly treated as uncacheable.

Fixes: f7bfb57b3e89ff89c0da9f93dedab89f68d6ca27
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561
Signed-off-by: Alexis Dambricourt <alexis.dambricourt at gmail.com>
[Use correct BZ for "Fixes" annotation.  - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/x86/kvm/mtrr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index 9e8bf13..adc54e1 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -267,7 +267,7 @@ static int fixed_mtrr_addr_to_seg(u64 addr)

 	for (seg = 0; seg < seg_num; seg++) {
 		mtrr_seg = &fixed_seg_table[seg];
-		if (mtrr_seg->start >= addr && addr < mtrr_seg->end)
+		if (mtrr_seg->start <= addr && addr < mtrr_seg->end)
 			return seg;
 	}

--
1.9.1