Jörg, On Mon, 30 Apr 2018, Jörg Otte wrote: > In v4.16 I already had support for BPB, IBRS_FW for spectre_v2 mitigation. > But this went away in v17-rcx. > > With 4.16 I have: > jojo@fichte:~$ cd /sys/devices/system/cpu/vulnerabilities; grep ".*" * > meltdown:Mitigation: PTI > spectre_v1:Mitigation: __user pointer sanitization > spectre_v2:Mitigation: Full generic retpoline, IBPB, IBRS_FW > > With 4.17-rcx I have: > meltdown:Mitigation: PTI > spectre_v1:Mitigation: __user pointer sanitization > spectre_v2:Mitigation: Full generic retpoline > > Processor is > vendor_id : GenuineIntel > cpu family : 6 > model : 60 > model name : Intel(R) Core(TM) i5-4200M CPU @ 2.50GHz > stepping : 3 > microcode : 0x24 > > > The problem goes away if I revert: > d94a155 x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption Does the patch below fix the problem for you? Thanks, tglx 8<------------------ Subject: x86/cpu: Restore CPUID_8000_0008_EBX reload From: Thomas Gleixner Date: Mon, 30 Apr 2018 21:47:46 +0200 The recent commt which addresses the x86_phys_bits corruption with encrypted memory on CPUID reload after a microcode update lost the reload of CPUID_8000_0008_EBX as well. As a consequence IBRS and IBRS_FW are not longer detected Restore the behaviour by bringing the reload of CPUID_8000_0008_EBX back,. Fixes: d94a155c59c9 ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption") Reported-by: Jörg Otte Signed-off-by: Thomas Gleixner Cc: kirill.shutemov@linux.intel.com --- arch/x86/kernel/cpu/common.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -848,6 +848,11 @@ void get_cpu_cap(struct cpuinfo_x86 *c) c->x86_power = edx; } + if (c->extended_cpuid_level >= 0x80000008) { + cpuid(0x80000008, &eax, &ebx, &ecx, &edx); + c->x86_capability[CPUID_8000_0008_EBX] = ebx; + } + if (c->extended_cpuid_level >= 0x8000000a) c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);