xen: suppress known wrmsrs
In general, Xen doesn't support wrmsr from an unprivileged domain; it
just ends up ignoring the instruction and printing a message on the
console.
Given that there are sets of MSRs we know the kernel will try to write
to, but we don't care, just eat them in xen_write_msr to cut down on
console noise.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b011e4a..b795470 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -854,6 +854,19 @@
ret = -EFAULT;
break;
#endif
+
+ case MSR_STAR:
+ case MSR_CSTAR:
+ case MSR_LSTAR:
+ case MSR_SYSCALL_MASK:
+ case MSR_IA32_SYSENTER_CS:
+ case MSR_IA32_SYSENTER_ESP:
+ case MSR_IA32_SYSENTER_EIP:
+ /* Fast syscall setup is all done in hypercalls, so
+ these are all ignored. Stub them out here to stop
+ Xen console noise. */
+ break;
+
default:
ret = native_write_msr_safe(msr, low, high);
}