Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7940C433EF for ; Thu, 16 Dec 2021 15:47:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238674AbhLPPrx (ORCPT ); Thu, 16 Dec 2021 10:47:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232741AbhLPPrw (ORCPT ); Thu, 16 Dec 2021 10:47:52 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9299C061574; Thu, 16 Dec 2021 07:47:51 -0800 (PST) Received: from zn.tnic (dslb-088-067-202-008.088.067.pools.vodafone-ip.de [88.67.202.8]) (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 0A6E51EC01A2; Thu, 16 Dec 2021 16:47:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1639669666; 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=w2zw5w9zdbclGVjd2mcfzFrzgn7sBAWZNCdTsQYykhk=; b=HOSNWrPkxPtVrP+QzbncJoQNAqagO6/nOkVG3sXbVKWfE/24GyfWge5/8230enJQIghU91 CeCqrdvkWGJYi0yOX1vOhtgg49xfGrdlGoiWDGDG64jPbOh+vwbdb5cViWyGbFySlIelWH iebgN19BrUYcG6qBiaDh42Sp3lSWbhI= Date: Thu, 16 Dec 2021 16:47:46 +0100 From: Borislav Petkov To: Brijesh Singh Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, Thomas Gleixner , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , "Dr . David Alan Gilbert" , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH v8 06/40] x86/sev: Check SEV-SNP features support Message-ID: References: <20211210154332.11526-1-brijesh.singh@amd.com> <20211210154332.11526-7-brijesh.singh@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211210154332.11526-7-brijesh.singh@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 10, 2021 at 09:42:58AM -0600, Brijesh Singh wrote: > Version 2 of the GHCB specification added the advertisement of features > that are supported by the hypervisor. If hypervisor supports the SEV-SNP > then it must set the SEV-SNP features bit to indicate that the base > SEV-SNP is supported. > > Check the SEV-SNP feature while establishing the GHCB, if failed, > terminate the guest. > > Version 2 of GHCB specification adds several new NAEs, most of them are > optional except the hypervisor feature. Now that hypervisor feature NAE > is implemented, so bump the GHCB maximum support protocol version. > > While at it, move the GHCB protocol negotitation check from VC exception Unknown word [negotitation] in commit message, suggestions: ['negotiation', 'negotiator', 'negotiate', 'abnegation', 'vegetation'] > handler to sev_enable() so that all feature detection happens before > the first VC exception. > > Signed-off-by: Brijesh Singh > --- > arch/x86/boot/compressed/sev.c | 21 ++++++++++++++++----- > arch/x86/include/asm/sev-common.h | 6 ++++++ > arch/x86/include/asm/sev.h | 2 +- > arch/x86/include/uapi/asm/svm.h | 2 ++ > arch/x86/kernel/sev-shared.c | 20 ++++++++++++++++++++ > arch/x86/kernel/sev.c | 16 ++++++++++++++++ > 6 files changed, 61 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c > index 0b6cc6402ac1..a0708f359a46 100644 > --- a/arch/x86/boot/compressed/sev.c > +++ b/arch/x86/boot/compressed/sev.c > @@ -119,11 +119,8 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, > /* Include code for early handlers */ > #include "../../kernel/sev-shared.c" > > -static bool early_setup_sev_es(void) > +static bool early_setup_ghcb(void) > { > - if (!sev_es_negotiate_protocol()) > - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED); > - > if (set_page_decrypted((unsigned long)&boot_ghcb_page)) > return false; > > @@ -174,7 +171,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code) > struct es_em_ctxt ctxt; > enum es_result result; > > - if (!boot_ghcb && !early_setup_sev_es()) > + if (!boot_ghcb && !early_setup_ghcb()) > sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); Can you setup the GHCB in sev_enable() too, after the protocol version negotiation succeeds? > vc_ghcb_invalidate(boot_ghcb); > @@ -247,5 +244,19 @@ void sev_enable(struct boot_params *bp) > if (!(sev_status & MSR_AMD64_SEV_ENABLED)) > return; > > + /* Negotiate the GHCB protocol version */ > + if (sev_status & MSR_AMD64_SEV_ES_ENABLED) > + if (!sev_es_negotiate_protocol()) > + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED); > + > + /* > + * SNP is supported in v2 of the GHCB spec which mandates support for HV > + * features. If SEV-SNP is enabled, then check if the hypervisor supports > + * the SEV-SNP features. > + */ > + if (sev_status & MSR_AMD64_SEV_SNP_ENABLED && !(get_hv_features() & GHCB_HV_FT_SNP)) > + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); > + > + ^ Superfluous newline. > sme_me_mask = BIT_ULL(ebx & 0x3f); ... > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 19ad09712902..a0cada8398a4 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -43,6 +43,10 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); > */ > static struct ghcb __initdata *boot_ghcb; > > +/* Bitmap of SEV features supported by the hypervisor */ > +static u64 sev_hv_features; __ro_after_init > + > + > /* #VC handler runtime per-CPU data */ > struct sev_es_runtime_data { > struct ghcb ghcb_page; > @@ -766,6 +770,18 @@ void __init sev_es_init_vc_handling(void) > if (!sev_es_check_cpu_features()) > panic("SEV-ES CPU Features missing"); > > + /* > + * SNP is supported in v2 of the GHCB spec which mandates support for HV > + * features. If SEV-SNP is enabled, then check if the hypervisor supports s/SEV-SNP/SNP/g And please do that everywhere in sev-specific files. This file is called sev.c and there's way too many acronyms flying around so the simpler the better. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette