x86, amd, xen: Avoid NULL pointer paravirt references

commit 1ab46fd319bcf1fcd9fb6311727d532b580e4eba upstream.

Stub out MSR methods that aren't actually needed.  This fixes a crash
as Xen Dom0 on AMD Trinity systems.  A bigger patch should be added to
remove the paravirt machinery completely for the methods which
apparently have no users!

Reported-by: Andre Przywara <andre.przywara@amd.com>
Link: http://lkml.kernel.org/r/20120530222356.GA28417@andromeda.dapyr.net
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 95dccce..6c7f1e8 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1106,7 +1106,10 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
        .wbinvd = native_wbinvd,
 
        .read_msr = native_read_msr_safe,
+       .rdmsr_regs = native_rdmsr_safe_regs,
        .write_msr = xen_write_msr_safe,
+       .wrmsr_regs = native_wrmsr_safe_regs,
+
        .read_tsc = native_read_tsc,
        .read_pmc = native_read_pmc,