tree 9d072863197b587504b9fe498c7e8d87a3b118eb
parent 1cdffecc34ba5d5af61b456fb0f46abbb3a86816
author Andi Kleen <ak@linux.intel.com> 1547859023 -0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1557854380 +0200

x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests

commit 6c4dbbd14730c43f4ed808a9c42ca41625925c22 upstream.

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>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>