Commit-ID: 36268223c1e9981d6cfc33aff8520b3bde4b8114 Gitweb: https://git.kernel.org/tip/36268223c1e9981d6cfc33aff8520b3bde4b8114 Author: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> AuthorDate: Mon, 26 Feb 2018 09:35:01 -0500 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Thu, 8 Mar 2018 10:13:02 +0100 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@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Cc: Wanpeng Li <kernellwp@xxxxxxxxx> Cc: kvm <kvm@xxxxxxxxxxxxxxx> Cc: Krčmář <rkrcmar@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> CC: "H. Peter Anvin" <hpa@xxxxxxxxx> CC: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20180226213019.GE9497@xxxxxxxxxxxxxxxxxx --- arch/x86/kernel/cpu/intel.c | 7 +++++++ 1 file changed, 7 insertions(+) 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)
