On 01/12/2014 22:57, Konrad Rzeszutek Wilk wrote: > On Mon, Dec 01, 2014 at 04:27:44PM -0500, Boris Ostrovsky wrote: >> Paravirtual guests are not expected to load microcode into processors >> and therefore it is not necessary to initialize microcode loading >> logic. > > CC-ing the KVM folks since they use the paravirt interface too.
We also do not want to load microcode. :) Thanks for the heads-up. Acked-by: Paolo Bonzini <pbonz...@redhat.com> Paolo >> In fact, under certain circumstances initializing this logic may cause >> the guest to crash. Specifically, 32-bit kernels use __pa_nodebug() >> macro which does not work in Xen (the code path that leads to this macro >> happens during resume when we call mc_bp_resume()->load_ucode_ap() >> ->check_loader_disabled_ap()) >> >> Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com> >> --- >> arch/x86/kernel/cpu/microcode/core.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/microcode/core.c >> b/arch/x86/kernel/cpu/microcode/core.c >> index 2ce9051..ebd232d 100644 >> --- a/arch/x86/kernel/cpu/microcode/core.c >> +++ b/arch/x86/kernel/cpu/microcode/core.c >> @@ -557,7 +557,7 @@ static int __init microcode_init(void) >> struct cpuinfo_x86 *c = &cpu_data(0); >> int error; >> >> - if (dis_ucode_ldr) >> + if (paravirt_enabled() || dis_ucode_ldr) >> return 0; >> >> if (c->x86_vendor == X86_VENDOR_INTEL) >> -- >> 1.7.1 >> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
