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authorAndi Kleen <ak@linux.intel.com>2019-01-18 16:50:23 -0800
committerThomas Gleixner <tglx@linutronix.de>2019-03-06 21:52:12 +0100
commit6c4dbbd14730c43f4ed808a9c42ca41625925c22 (patch)
treeeafd317aa2a6e4db02b9bceb29461fa9568b82b2
parentx86/speculation/mds: Add BUG_MSBDS_ONLY (diff)
downloadlinux-dev-6c4dbbd14730c43f4ed808a9c42ca41625925c22.tar.xz
linux-dev-6c4dbbd14730c43f4ed808a9c42ca41625925c22.zip
x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests
X86_FEATURE_MD_CLEAR is a new CPUID bit which is set when microcode provides the mechanism to invoke a flush of various exploitable CPU buffers by invoking the VERW instruction. Hand it through to guests so they can adjust their mitigations. This also requires corresponding qemu changes, which are available separately. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com>
-rw-r--r--arch/x86/kvm/cpuid.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index c07958b59f50..39501e7afdb4 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -410,7 +410,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
- F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP);
+ F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
+ F(MD_CLEAR);
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();