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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 4836DC4743F for ; Mon, 7 Jun 2021 06:41:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E4926121D for ; Mon, 7 Jun 2021 06:41:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230258AbhFGGnn (ORCPT ); Mon, 7 Jun 2021 02:43:43 -0400 Received: from verein.lst.de ([213.95.11.211]:44563 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbhFGGnj (ORCPT ); Mon, 7 Jun 2021 02:43:39 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id C9F1667373; Mon, 7 Jun 2021 08:41:42 +0200 (CEST) Date: Mon, 7 Jun 2021 08:41:42 +0200 From: Christoph Hellwig To: Tianyu Lan Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, rppt@kernel.org, hannes@cmpxchg.org, cai@lca.pw, krish.sadhukhan@oracle.com, saravanand@fb.com, Tianyu.Lan@microsoft.com, konrad.wilk@oracle.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, joro@8bytes.org, will@kernel.org, xen-devel@lists.xenproject.org, davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com, iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, netdev@vger.kernel.org, vkuznets@redhat.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, sunilmut@microsoft.com Subject: Re: [RFC PATCH V3 01/11] x86/HV: Initialize GHCB page in Isolation VM Message-ID: <20210607064142.GA24478@lst.de> References: <20210530150628.2063957-1-ltykernel@gmail.com> <20210530150628.2063957-2-ltykernel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210530150628.2063957-2-ltykernel@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 30, 2021 at 11:06:18AM -0400, Tianyu Lan wrote: > + if (ms_hyperv.ghcb_base) { > + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); > + > + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE); > + if (!ghcb_va) > + return -ENOMEM; Can you explain this a bit more? We've very much deprecated ioremap_cache in favor of memremap. Why yo you need a __iomem address here? Why do we need the remap here at all? Does the data structure at this address not have any types that we could use a struct for? > + > + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); > + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE); > + if (!ghcb_va) { This seems to duplicate the above code. > +bool hv_isolation_type_snp(void) > +{ > + return static_branch_unlikely(&isolation_type_snp); > +} > +EXPORT_SYMBOL_GPL(hv_isolation_type_snp); This probably wants a kerneldoc explaining when it should be used.