[Xen-changelog] [xen stable-4.8] x86/PV: fix off-by-one in I/O bitmap limit check

[patchbot@xxxxxxx]

commit a442d40e9b4269845bd1eec58d406b5ad03a4ccb
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Mar 6 16:15:32 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 6 16:15:32 2018 +0100

    x86/PV: fix off-by-one in I/O bitmap limit check
    
    With everyone having their tags below agreeing that putting things the
    other way around in the comparison makes things easier to understand, do
    that rearrangement while changing the line anyway.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.apu@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: c6527bc66b6dd7a8dadaebb1047c8e52c6c5793c
    master date: 2018-02-27 14:10:00 +0100
---
 xen/arch/x86/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 820f94b1eb..480094a93a 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -2061,7 +2061,7 @@ static int guest_io_okay(
     if ( iopl_ok(v, regs) )
         return 1;
 
-    if ( v->arch.pv_vcpu.iobmp_limit > (port + bytes) )
+    if ( (port + bytes) <= v->arch.pv_vcpu.iobmp_limit )
     {
         union { uint8_t bytes[2]; uint16_t mask; } x;
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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