x86/cpufeatures: Add AMD feature bits for Speculation Control

AMD exposes the PRED_CMD/SPEC_CTRL MSRs slightly differently to Intel.
See http://lkml.kernel.org/r/2b3e25cc-286d-8bd0-aeaf-9ac4aae39de8@amd.com

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: ak@linux.intel.com
Cc: ashok.raj@intel.com
Cc: dave.hansen@intel.com
Cc: karahmed@amazon.de
Cc: arjan@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: pbonzini@redhat.com
Cc: tim.c.chen@linux.intel.com
Cc: gregkh@linux-foundation.org
Link: https://lkml.kernel.org/r/1516896855-7642-4-git-send-email-dwmw@amazon.co.uk
 Conflicts:
	arch/x86/include/asm/cpufeatures.h
[Upstream has the NCAPINTS raised so there is another array to stuff all the
 0x80000008 cpuid leaf in. But we don't have that so we just toggle the global
 ones]

Orabug: 27477743
CVE: CVE-2017-5715

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index b4b794f1102204c1a2da9de63e6b0b6dd207b798..892972ff4137e7a50888eb259023a5dbd350bc06 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -754,9 +754,13 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
 
                c->x86_virt_bits = (eax >> 8) & 0xff;
                c->x86_phys_bits = eax & 0xff;
-               /* Only look for X86_FEATURE_IBPB. */
+               /* Only look for X86_FEATURE_{IBPB, SPEC_CTRL, STIBP}. */
                if (ebx & BIT(12))
                        set_cpu_cap(c, X86_FEATURE_IBPB);
+               if (ebx & BIT(14))
+                       set_cpu_cap(c, X86_FEATURE_SPEC_CTRL);
+               if (ebx & BIT(15))
+                       set_cpu_cap(c, X86_FEATURE_STIPB);
        }
 #ifdef CONFIG_X86_32
        else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))