From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934881AbcLPQhk (ORCPT ); Fri, 16 Dec 2016 11:37:40 -0500 Received: from mail.skyhub.de ([78.46.96.112]:45718 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752528AbcLPQhc (ORCPT ); Fri, 16 Dec 2016 11:37:32 -0500 Date: Fri, 16 Dec 2016 17:37:25 +0100 From: Borislav Petkov To: Boris Ostrovsky Cc: x86@kernel.org, linux-kernel@vger.kernel.org, jgross@suse.com, xen-devel@lists.xenproject.org Subject: Re: [PATCH] x86/microcode: Use native_cpuid() in load_ucode_amd_bsp() Message-ID: <20161216163725.uxrvtsq3qvzwwrs5@pd.tnic> References: <1481906392-3847-1-git-send-email-boris.ostrovsky@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1481906392-3847-1-git-send-email-boris.ostrovsky@oracle.com> User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 16, 2016 at 11:39:52AM -0500, Boris Ostrovsky wrote: > When CONFIG_PARAVIRT is selected, cpuid() becomes a call. Since > for 32-bit kernels load_ucode_amd_bsp() is executed before paging > is enabled the call cannot be completed (as kernel virtual addresses > are not reachable yet). > > Use native_cpuid() instead which is an asm wrapper for CPUID instruction. > > Signed-off-by: Boris Ostrovsky > --- > arch/x86/kernel/cpu/microcode/amd.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c > index 6f353bd..e2d941f 100644 > --- a/arch/x86/kernel/cpu/microcode/amd.c > +++ b/arch/x86/kernel/cpu/microcode/amd.c > @@ -297,6 +297,7 @@ void __init load_ucode_amd_bsp(unsigned int family) > struct cpio_data cp; > const char *path; > bool use_pa; > + u32 eax, ebx, ecx, edx; > > if (IS_ENABLED(CONFIG_X86_32)) { > uci = (struct ucode_cpu_info *)__pa_nodebug(ucode_cpu_info); > @@ -315,7 +316,10 @@ void __init load_ucode_amd_bsp(unsigned int family) > return; > > /* Get BSP's CPUID.EAX(1), needed in load_microcode_amd() */ > - uci->cpu_sig.sig = cpuid_eax(1); > + eax = 0x00000001; > + ecx = 0; > + native_cpuid(&eax, &ebx, &ecx, &edx); > + uci->cpu_sig.sig = eax; > > apply_microcode_early_amd(cp.data, cp.size, true); > } > -- Applied, thanks. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.