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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2018-02-26 17:35:01 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-03-08 12:13:02 +0300
commit36268223c1e9981d6cfc33aff8520b3bde4b8114 (patch)
tree18cae517b606794c28c39d0446b55c99b9e80612 /arch
parent076ca272a14cea558b1092ec85cea08510283f2a (diff)
downloadlinux-36268223c1e9981d6cfc33aff8520b3bde4b8114.tar.xz
x86/spectre_v2: Don't check microcode versions when running under hypervisors
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
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/intel.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index d19e903214b4..4aa9fd379390 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -144,6 +144,13 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
{
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)