4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Juergen Gross <[email protected]> Revert commit 944e0fc51a89c9827b98813d65dc083274777c7f ("x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen") as it is lacking a prerequisite patch and is making things worse. Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/cpu/amd.c | 5 ++--- arch/x86/xen/enlighten.c | 4 +++- 2 files changed, 5 insertions(+), 4 deletions(-) --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -857,9 +857,8 @@ static void init_amd(struct cpuinfo_x86 if (cpu_has(c, X86_FEATURE_3DNOW) || cpu_has(c, X86_FEATURE_LM)) set_cpu_cap(c, X86_FEATURE_3DNOWPREFETCH); - /* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */ - if (!cpu_has(c, X86_FEATURE_XENPV)) - set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); + /* AMD CPUs don't reset SS attributes on SYSRET */ + set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); } #ifdef CONFIG_X86_32 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1980,8 +1980,10 @@ EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); static void xen_set_cpu_features(struct cpuinfo_x86 *c) { - if (xen_pv_domain()) + if (xen_pv_domain()) { + clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); set_cpu_cap(c, X86_FEATURE_XENPV); + } } static void xen_pin_vcpu(int cpu)
