From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AD5FC4338F for ; Tue, 24 Aug 2021 18:01:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2A7F610F7 for ; Tue, 24 Aug 2021 18:01:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238502AbhHXSCR (ORCPT ); Tue, 24 Aug 2021 14:02:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239149AbhHXSCI (ORCPT ); Tue, 24 Aug 2021 14:02:08 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2019C061B3C for ; Tue, 24 Aug 2021 10:48:00 -0700 (PDT) Received: from zn.tnic (p200300ec2f114400ce3b938495d443bc.dip0.t-ipconnect.de [IPv6:2003:ec:2f11:4400:ce3b:9384:95d4:43bc]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 37E691EC04D1; Tue, 24 Aug 2021 19:47:55 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1629827275; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=HaBtrWrajmGcfbWLYhDUsIXaLchGb1bstlD6N7edDYs=; b=g6VPThMZAQl+bN5jor6udrLQHslQI+kWjkakwucuN3cXS4VSEBJnQaGykKZw7VXPTuj4Yk sQq2QARrjzij8NZtkXOTwE+XyVBZbJ5DLqaZTd+mDSHj9VaekRNBGNdOerq3Q+Ne5yi1ui FNYhVfDNjhQoDort5l3IUEfHd3xabuo= Date: Tue, 24 Aug 2021 19:48:37 +0200 From: Borislav Petkov To: Kuppuswamy Sathyanarayanan Cc: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Andy Lutomirski , Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 12/12] x86/tdx: Handle CPUID via #VE Message-ID: References: <20210804181329.2899708-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20210804181329.2899708-13-sathyanarayanan.kuppuswamy@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210804181329.2899708-13-sathyanarayanan.kuppuswamy@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 04, 2021 at 11:13:29AM -0700, Kuppuswamy Sathyanarayanan wrote: > From: "Kirill A. Shutemov" > > TDX has three classes of CPUID leaves: some CPUID leaves > are always handled by the CPU, others are handled by the TDX module, > and some others are handled by the VMM. Since the VMM cannot directly > intercept the instruction these are reflected with a #VE exception > to the guest, which then converts it into a hypercall to the VMM, > or handled directly. > > The TDX module EAS has a full list of CPUID leaves which are handled EAS? > natively or by the TDX module in 16.2. Only unknown CPUIDs are handled by 16.2? I believe that commit message was forgotten to be converted to outside-Intel speak. Please do so. > the #VE method. In practice this typically only applies to the > hypervisor specific CPUIDs unknown to the native CPU. hypervisor-specific > Therefore there is no risk of causing this in early CPUID code which > runs before the #VE handler is set up because it will never access > those exotic CPUID leaves. > > Signed-off-by: Kirill A. Shutemov > Reviewed-by: Andi Kleen > Reviewed-by: Tony Luck > Signed-off-by: Kuppuswamy Sathyanarayanan > --- > > Changes since v4: > * None > > Changes since v3: > * None > > arch/x86/kernel/tdx.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c > index d16c7f8759ea..5d2fd6c8b01c 100644 > --- a/arch/x86/kernel/tdx.c > +++ b/arch/x86/kernel/tdx.c > @@ -153,6 +153,21 @@ static int tdg_write_msr_safe(unsigned int msr, unsigned int low, > return ret ? -EIO : 0; > } > > +static void tdg_handle_cpuid(struct pt_regs *regs) > +{ > + u64 ret; > + struct tdx_hypercall_output out = {0}; > + > + ret = _tdx_hypercall(EXIT_REASON_CPUID, regs->ax, regs->cx, 0, 0, &out); > + > + WARN_ON(ret); Why warn and not forward the error, instead, so that it lands in ve_raise_fault() ? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette