x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests

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commit 6c4dbbd147 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 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

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Andi Kleen 2019-01-18 16:50:23 -08:00 • committed by Ben Hutchings

parent 8a73fd7fa6

commit 5b4088f4ee

1 changed files with 1 additions and 1 deletions

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arch/x86/kvm/cpuid.c

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