xen: mask out SEP from CPUID

upstream commit: d40e705903397445c6861a0a56c23e5b2e8f9b9a

Fix 32-on-64 pvops kernel:

we don't want userspace using syscall/sysenter, even if the hypervisor
supports it, so mask it out from CPUID.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b6af3ea43c7308b3e513272ccb5c9c0f6c224717..228f6c729bccb9b421819cc18912f939722d46be 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -153,6 +153,7 @@ static void xen_cpuid(unsigned int *eax, unsigned int *ebx,
        if (*eax == 1)
                maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
                            (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
+                           (1 << X86_FEATURE_SEP)  |  /* disable SEP */
                            (1 << X86_FEATURE_ACC));   /* thermal monitoring */
 
        asm(XEN_EMULATE_PREFIX "cpuid"