This is a note to let you know that I've just added the patch titled
x86/spectre_v2: Don't check microcode versions when running under hypervisors
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-spectre_v2-don-t-check-microcode-versions-when-running-under-hypervisors.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 36268223c1e9981d6cfc33aff8520b3bde4b8114 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Date: Mon, 26 Feb 2018 09:35:01 -0500 Subject: x86/spectre_v2: Don't check microcode versions when running under hypervisors MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
From: Konrad Rzeszutek Wilk konrad.wilk@oracle.com
commit 36268223c1e9981d6cfc33aff8520b3bde4b8114 upstream.
As:
1) It's known that hypervisors lie about the environment anyhow (host mismatch)
2) Even if the hypervisor (Xen, KVM, VMWare, etc) provided a valid "correct" value, it all gets to be very murky when migration happens (do you provide the "new" microcode of the machine?).
And in reality the cloud vendors are the ones that should make sure that the microcode that is running is correct and we should just sing lalalala and trust them.
Signed-off-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Paolo Bonzini pbonzini@redhat.com Cc: Wanpeng Li kernellwp@gmail.com Cc: kvm kvm@vger.kernel.org Cc: Krčmář rkrcmar@redhat.com Cc: Borislav Petkov bp@alien8.de CC: "H. Peter Anvin" hpa@zytor.com CC: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180226213019.GE9497@char.us.oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/intel.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -144,6 +144,13 @@ static bool bad_spectre_microcode(struct { int i;
+ /* + * We know that the hypervisor lie to us on the microcode version so + * we may as well hope that it is running the correct version. + */ + if (cpu_has(c, X86_FEATURE_HYPERVISOR)) + return false; + for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) { if (c->x86_model == spectre_bad_microcodes[i].model && c->x86_stepping == spectre_bad_microcodes[i].stepping)
Patches currently in stable-queue which might be from konrad.wilk@oracle.com are
queue-4.14/x86-spectre_v2-don-t-check-microcode-versions-when-running-under-hypervisors.patch