x86/speculation: Use synthetic bits for IBRS/IBPB/STIBP

commit e7c587da125291db39ddf1f49b18e5970adbac17 upstream.

Intel and AMD have different CPUID bits hence for those use synthetic bits
which get set on the respective vendor's in init_speculation_control(). So
that debacles like what the commit message of

  c65732e4f721 ("x86/cpu: Restore CPUID_8000_0008_EBX reload")

talks about don't happen anymore.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Jörg Otte <jrg.otte@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: https://lkml.kernel.org/r/20180504161815.GG9257@pd.tnic
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 4.4: This was partly applied before; apply just the
 missing bits]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6b20e0a823da762fe0cc8210cdfe08d72d5ba1e7..b0371a77cbc8b00c9445f9e0205d487f84901bab 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -343,7 +343,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 
        /* cpuid 0x80000008.ebx */
        const u32 kvm_cpuid_8000_0008_ebx_x86_features =
-               F(IBPB) | F(IBRS);
+               F(AMD_IBPB) | F(AMD_IBRS);
 
        /* cpuid 0xC0000001.edx */
        const u32 kvm_supported_word5_x86_features =
@@ -596,10 +596,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                entry->eax = g_phys_as | (virt_as << 8);
                entry->edx = 0;
                /* IBRS and IBPB aren't necessarily present in hardware cpuid */
-               if (boot_cpu_has(X86_FEATURE_IBPB))
-                       entry->ebx |= F(IBPB);
-               if (boot_cpu_has(X86_FEATURE_IBRS))
-                       entry->ebx |= F(IBRS);
+               if (boot_cpu_has(X86_FEATURE_AMD_IBPB))
+                       entry->ebx |= F(AMD_IBPB);
+               if (boot_cpu_has(X86_FEATURE_AMD_IBRS))
+                       entry->ebx |= F(AMD_IBRS);
                entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;
                cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);
                break;

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 31ff5d2d05369c3ad0ce6f63aeb161cbb2cdbfc8..ba8988707e9dd4ffabe538c046801f94a7ac6bee 100644 (file)
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -164,7 +164,7 @@ static inline bool guest_cpuid_has_ibpb(struct kvm_vcpu *vcpu)
        struct kvm_cpuid_entry2 *best;
 
        best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
-       if (best && (best->ebx & bit(X86_FEATURE_IBPB)))
+       if (best && (best->ebx & bit(X86_FEATURE_AMD_IBPB)))
                return true;
        best = kvm_find_cpuid_entry(vcpu, 7, 0);
        return best && (best->edx & bit(X86_FEATURE_SPEC_CTRL));
@@ -175,7 +175,7 @@ static inline bool guest_cpuid_has_spec_ctrl(struct kvm_vcpu *vcpu)
        struct kvm_cpuid_entry2 *best;
 
        best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
-       if (best && (best->ebx & bit(X86_FEATURE_IBRS)))
+       if (best && (best->ebx & bit(X86_FEATURE_AMD_IBRS)))
                return true;
        best = kvm_find_cpuid_entry(vcpu, 7, 0);
        return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | bit(X86_FEATURE_SPEC_CTRL_SSBD)));