tree 68f122e77b42a603f09d83148fa139f2a88ffb1d
parent 8a01dd38e5e1b06f9be73eb5eb80b267a236f29d
author Wanpeng Li <wanpengli@tencent.com> 1519797811 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1534349693 +0200

KVM: X86: Allow userspace to define the microcode version

commit 518e7b94817abed94becfe6a44f1ece0d4745afe upstream

Linux (among the others) has checks to make sure that certain features
aren't enabled on a certain family/model/stepping if the microcode version
isn't greater than or equal to a known good version.

By exposing the real microcode version, we're preventing buggy guests that
don't check that they are running virtualized (i.e., they should trust the
hypervisor) from disabling features that are effectively not buggy.

Suggested-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>