From a18a0f6850d4b286a5ebf02cd5b22fe496b86349 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky <boris.ostrovsky@oracle.com> Date: Mon, 1 Dec 2014 16:27:44 -0500 Subject: [PATCH] x86, microcode: Don't initialize microcode code on paravirt Paravirtual guests are not expected to load microcode into processors and therefore it is not necessary to initialize microcode loading logic. 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.ostrovsky@oracle.com> Link: http://lkml.kernel.org/r/1417469264-31470-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/kernel/cpu/microcode/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 2ce9051174e6..ebd232d7de4d 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) -- GitLab