vmxcap: Open MSR file in unbuffered mode

Python may otherwise decide to to read larger chunks, applying the seek
only on the software buffer. This will return results from the wrong
MSRs.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

diff --git a/scripts/kvm/vmxcap b/scripts/kvm/vmxcap
index 0b23f7795a32ccf36c64e130d2319fa28d6a6117..6363e7368f5aca4a4c9a530fc0e697d0a784aeef 100755 (executable)
--- a/scripts/kvm/vmxcap
+++ b/scripts/kvm/vmxcap
@@ -27,9 +27,9 @@ MSR_IA32_VMX_VMFUNC = 0x491
 class msr(object):
     def __init__(self):
         try:
 class msr(object):
     def __init__(self):
         try:

-            self.f = file('/dev/cpu/0/msr')
+            self.f = open('/dev/cpu/0/msr', 'r', 0)

         except:
         except:

-            self.f = file('/dev/msr0')
+            self.f = open('/dev/msr0', 'r', 0)

     def read(self, index, default = None):
         import struct
         self.f.seek(index)
     def read(self, index, default = None):
         import struct
         self.f.seek(index)