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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23726C433F5 for ; Wed, 8 Dec 2021 17:42:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8B8516B0071; Wed, 8 Dec 2021 12:42:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 840476B0073; Wed, 8 Dec 2021 12:42:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6BA6A6B0074; Wed, 8 Dec 2021 12:42:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 59E7B6B0071 for ; Wed, 8 Dec 2021 12:42:09 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 1816F8248076 for ; Wed, 8 Dec 2021 17:41:59 +0000 (UTC) X-FDA: 78895345158.07.6114685 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf08.hostedemail.com (Postfix) with ESMTP id 96A6F30000AD for ; Wed, 8 Dec 2021 17:41:50 +0000 (UTC) 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 85D481EC04D3; Wed, 8 Dec 2021 18:41:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1638985303; 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=BVB1m3MrNRyz7QEt2fceR49E0yXRKK99UJ6lToflU+M=; b=plYDMSSdy0AlmPWLQfXS/7oOeIwQCRt1HOSpB0McPkEavfxw4f8gLgIuMdXHY83gDJ/xJX 0RCjuXJK2+CkfQfDA6ItGYTPBrLza2XhPdTQUw/RYpNqE9/f6br44Xd7qmGMcAVyb8g9yN XehNfufGbEq41gGE3w/dhMtObAW6vXE= Date: Wed, 8 Dec 2021 18:41:46 +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 v7 16/45] x86/sev: Register GHCB memory when SEV-SNP is active Message-ID: References: <20211110220731.2396491-1-brijesh.singh@amd.com> <20211110220731.2396491-17-brijesh.singh@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211110220731.2396491-17-brijesh.singh@amd.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 96A6F30000AD X-Stat-Signature: gkgd6sdbcc7rgw8uk56irb3d8j69cqho Authentication-Results: imf08.hostedemail.com; dkim=temperror ("DNS error when getting key") header.d=alien8.de header.s=dkim header.b=plYDMSSd; spf=temperror (imf08.hostedemail.com: error in processing during lookup of bp@alien8.de: DNS error) smtp.mailfrom=bp@alien8.de; dmarc=temperror reason="query timed out" header.from=alien8.de (policy=temperror) X-HE-Tag: 1638985310-631355 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Nov 10, 2021 at 04:07:02PM -0600, Brijesh Singh wrote: > The SEV-SNP guest is required to perform GHCB GPA registration. This is > because the hypervisor may prefer that a guest use a consistent and/or > specific GPA for the GHCB associated with a vCPU. For more information, > see the GHCB specification section GHCB GPA Registration. > > During the boot, init_ghcb() allocates a per-cpu GHCB page. On very first > VC exception, That is not true anymore - you're doing proper init at init time - no more #VC hackery. > @@ -1977,6 +1978,10 @@ void cpu_init_exception_handling(void) > > load_TR_desc(); > > + /* Register the GHCB before taking any VC exception */ > + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) No need for that if branch - sev_snp_register_ghcb() already has an empty stub for the !CONFIG_AMD_MEM_ENCRYPT case so you can simply call it unconditionally. > + sev_snp_register_ghcb(); > + > /* Finally load the IDT */ > load_current_idt(); > } > diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c > index 54bf0603002f..968105cec364 100644 > --- a/arch/x86/kernel/head64.c > +++ b/arch/x86/kernel/head64.c > @@ -588,6 +588,9 @@ void early_setup_idt(void) > > bringup_idt_descr.address = (unsigned long)bringup_idt_table; > native_load_idt(&bringup_idt_descr); > + > + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) > + sev_snp_register_ghcb(); Ditto. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette