xen/x86: Don't try to write syscall-related MSRs for PV guests
authorBoris Ostrovsky <boris.ostrovsky@oracle.com>
Mon, 21 Sep 2015 13:09:28 +0000 (09:09 -0400)
committerDavid Vrabel <david.vrabel@citrix.com>
Mon, 28 Sep 2015 13:48:52 +0000 (14:48 +0100)
For PV guests these registers are set up by hypervisor and thus
should not be written by the guest. The comment in xen_write_msr_safe()
says so but we still write the MSRs, causing the hypervisor to
print a warning.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
arch/x86/xen/enlighten.c

index 30d12afe52ed173b2a81720cd5c89c24e667de2a..1f1dbd2949a4abcdc815a9e1226e0c260f108a2a 100644 (file)
@@ -1077,6 +1077,7 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
                /* Fast syscall setup is all done in hypercalls, so
                   these are all ignored.  Stub them out here to stop
                   Xen console noise. */
+               break;
 
        default:
                if (!pmu_msr_write(msr, low, high, &ret))