[Xen-changelog] [xen stable-4.10] x86/PV: fix off-by-one in I/O bitmap limit check

[patchbot@xxxxxxx]

commit 5ede9f9600f7eef9e5da34bc68e445b17eb5d8db
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Mar 6 15:55:33 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 6 15:55:33 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/pv/emul-priv-op.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index b965b3ece7..642ca312bf 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -145,7 +145,7 @@ static bool guest_io_okay(unsigned int port, unsigned int 
bytes,
     if ( iopl_ok(v, regs) )
         return true;
 
-    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-4.10

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