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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 60E3BC004D5 for ; Sat, 29 Sep 2018 09:36:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 317AC206B7 for ; Sat, 29 Sep 2018 09:36:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 317AC206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727954AbeI2QEH (ORCPT ); Sat, 29 Sep 2018 12:04:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48692 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727540AbeI2QEH (ORCPT ); Sat, 29 Sep 2018 12:04:07 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E3C130001EF; Sat, 29 Sep 2018 09:36:22 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-53.pek2.redhat.com [10.72.12.53]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 319FB5C1A1; Sat, 29 Sep 2018 09:36:07 +0000 (UTC) Subject: Re: [PATCH v7 RESEND 4/4] kdump/vmcore: support encrypted old memory with SME enabled To: Borislav Petkov Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, akpm@linux-foundation.org, dan.j.williams@intel.com, thomas.lendacky@amd.com, bhelgaas@google.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de, brijesh.singh@amd.com, dyoung@redhat.com, bhe@redhat.com, jroedel@suse.de References: <20180927071954.29615-1-lijiang@redhat.com> <20180927071954.29615-5-lijiang@redhat.com> <20180928083852.GA21895@zn.tnic> <1c27b9a9-ae93-011a-b003-a50ecc22ccc5@redhat.com> <20180929083052.GA13786@zn.tnic> From: lijiang Message-ID: <76d9d338-2fc1-a8a5-8f12-c25d2ad092f3@redhat.com> Date: Sat, 29 Sep 2018 17:36:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180929083052.GA13786@zn.tnic> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Sat, 29 Sep 2018 09:36:22 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2018年09月29日 16:30, Borislav Petkov 写道: > On Sat, Sep 29, 2018 at 02:24:52PM +0800, lijiang wrote: >> At first, i added an input parameter for read_from_oldmem() because of encryption(SME). But >> for avoiding to also add the same parameter for copy_oldmem_page(), so i added a new function >> copy_oldmem_page_encrypted(). Maybe you had noticed that these functions were very similar. > > If you have two very similar functions, you add a *static* workhorse function: > > static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, > int userbuf, bool encrypted) > > and you define two wrappers: > > copy_oldmem_page() > copy_oldmem_page_encrypted() > > which both call __copy_oldmem_page() with the appropriate parameters. > Great! Previously i was afraid that the maintainer might disagree with rewriting the function copy_oldmem_page(). That's really great. I will modify this patch and post the series again. Thanks. Lianbo > But you do *not* do a separate compilation unit just because. None of > the reasons you've mentioned warrant having a separate compilation > unit while you already have *the* perfect place to put everything - > arch/x86/kernel/crash_dump_64.c > >> So sorry, here "oldmem encrypted" means the "old memory is encrypted". > > I know what it means - I'm trying to explain to you to write it out > in plain english and not use some strange constructs like "oldmem > encrypted". > > A reader would wonder: why is this thing semi-abbreviated and in > quotation marks? Does that mean anything special? > > Our comments should not be write-only. So after you've written it, try > to read it as someone who sees the code for the first time and think > hard whether she/he will understand it. > > Do you catch my drift now? > Yes, got it. Thanks for your valuable time and patience. Regards, Lianbo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1g6Bfv-00032N-ML for kexec@lists.infradead.org; Sat, 29 Sep 2018 09:36:37 +0000 Subject: Re: [PATCH v7 RESEND 4/4] kdump/vmcore: support encrypted old memory with SME enabled References: <20180927071954.29615-1-lijiang@redhat.com> <20180927071954.29615-5-lijiang@redhat.com> <20180928083852.GA21895@zn.tnic> <1c27b9a9-ae93-011a-b003-a50ecc22ccc5@redhat.com> <20180929083052.GA13786@zn.tnic> From: lijiang Message-ID: <76d9d338-2fc1-a8a5-8f12-c25d2ad092f3@redhat.com> Date: Sat, 29 Sep 2018 17:36:04 +0800 MIME-Version: 1.0 In-Reply-To: <20180929083052.GA13786@zn.tnic> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Borislav Petkov Cc: thomas.lendacky@amd.com, jroedel@suse.de, brijesh.singh@amd.com, bhe@redhat.com, tiwai@suse.de, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, baiyaowei@cmss.chinamobile.com, hpa@zytor.com, bhelgaas@google.com, tglx@linutronix.de, dyoung@redhat.com, akpm@linux-foundation.org, dan.j.williams@intel.com 5ZyoIDIwMTjlubQwOeaciDI55pelIDE2OjMwLCBCb3Jpc2xhdiBQZXRrb3Yg5YaZ6YGTOgo+IE9u IFNhdCwgU2VwIDI5LCAyMDE4IGF0IDAyOjI0OjUyUE0gKzA4MDAsIGxpamlhbmcgd3JvdGU6Cj4+ IEF0IGZpcnN0LCBpIGFkZGVkIGFuIGlucHV0IHBhcmFtZXRlciBmb3IgcmVhZF9mcm9tX29sZG1l bSgpIGJlY2F1c2Ugb2YgZW5jcnlwdGlvbihTTUUpLiBCdXQKPj4gZm9yIGF2b2lkaW5nIHRvIGFs c28gYWRkIHRoZSBzYW1lIHBhcmFtZXRlciBmb3IgY29weV9vbGRtZW1fcGFnZSgpLCBzbyBpIGFk ZGVkIGEgbmV3IGZ1bmN0aW9uCj4+IGNvcHlfb2xkbWVtX3BhZ2VfZW5jcnlwdGVkKCkuIE1heWJl IHlvdSBoYWQgbm90aWNlZCB0aGF0IHRoZXNlIGZ1bmN0aW9ucyB3ZXJlIHZlcnkgc2ltaWxhci4K PiAKPiBJZiB5b3UgaGF2ZSB0d28gdmVyeSBzaW1pbGFyIGZ1bmN0aW9ucywgeW91IGFkZCBhICpz dGF0aWMqIHdvcmtob3JzZSBmdW5jdGlvbjoKPiAKPiBzdGF0aWMgc3NpemVfdCBfX2NvcHlfb2xk bWVtX3BhZ2UodW5zaWduZWQgbG9uZyBwZm4sIGNoYXIgKmJ1Ziwgc2l6ZV90IGNzaXplLCB1bnNp Z25lZCBsb25nIG9mZnNldCwKPiAJCQkJICBpbnQgdXNlcmJ1ZiwgYm9vbCBlbmNyeXB0ZWQpCj4g Cj4gYW5kIHlvdSBkZWZpbmUgdHdvIHdyYXBwZXJzOgo+IAo+IGNvcHlfb2xkbWVtX3BhZ2UoKQo+ IGNvcHlfb2xkbWVtX3BhZ2VfZW5jcnlwdGVkKCkKPiAKPiB3aGljaCBib3RoIGNhbGwgX19jb3B5 X29sZG1lbV9wYWdlKCkgd2l0aCB0aGUgYXBwcm9wcmlhdGUgcGFyYW1ldGVycy4KPiAKCkdyZWF0 ISBQcmV2aW91c2x5IGkgd2FzIGFmcmFpZCB0aGF0IHRoZSBtYWludGFpbmVyIG1pZ2h0IGRpc2Fn cmVlIHdpdGgKcmV3cml0aW5nIHRoZSBmdW5jdGlvbiBjb3B5X29sZG1lbV9wYWdlKCkuCgpUaGF0 J3MgcmVhbGx5IGdyZWF0LiBJIHdpbGwgbW9kaWZ5IHRoaXMgcGF0Y2ggYW5kIHBvc3QgdGhlIHNl cmllcyBhZ2Fpbi4KClRoYW5rcy4KTGlhbmJvCj4gQnV0IHlvdSBkbyAqbm90KiBkbyBhIHNlcGFy YXRlIGNvbXBpbGF0aW9uIHVuaXQganVzdCBiZWNhdXNlLiBOb25lIG9mCj4gdGhlIHJlYXNvbnMg eW91J3ZlIG1lbnRpb25lZCB3YXJyYW50IGhhdmluZyBhIHNlcGFyYXRlIGNvbXBpbGF0aW9uCj4g dW5pdCB3aGlsZSB5b3UgYWxyZWFkeSBoYXZlICp0aGUqIHBlcmZlY3QgcGxhY2UgdG8gcHV0IGV2 ZXJ5dGhpbmcgLQo+IGFyY2gveDg2L2tlcm5lbC9jcmFzaF9kdW1wXzY0LmMKPiAKPj4gU28gc29y cnksIGhlcmUgIm9sZG1lbSBlbmNyeXB0ZWQiIG1lYW5zIHRoZSAib2xkIG1lbW9yeSBpcyBlbmNy eXB0ZWQiLgo+IAo+IEkga25vdyB3aGF0IGl0IG1lYW5zIC0gSSdtIHRyeWluZyB0byBleHBsYWlu IHRvIHlvdSB0byB3cml0ZSBpdCBvdXQKPiBpbiBwbGFpbiBlbmdsaXNoIGFuZCBub3QgdXNlIHNv bWUgc3RyYW5nZSBjb25zdHJ1Y3RzIGxpa2UgIm9sZG1lbQo+IGVuY3J5cHRlZCIuCj4gCj4gQSBy ZWFkZXIgd291bGQgd29uZGVyOiB3aHkgaXMgdGhpcyB0aGluZyBzZW1pLWFiYnJldmlhdGVkIGFu ZCBpbgo+IHF1b3RhdGlvbiBtYXJrcz8gRG9lcyB0aGF0IG1lYW4gYW55dGhpbmcgc3BlY2lhbD8K PiAKPiBPdXIgY29tbWVudHMgc2hvdWxkIG5vdCBiZSB3cml0ZS1vbmx5LiBTbyBhZnRlciB5b3Un dmUgd3JpdHRlbiBpdCwgdHJ5Cj4gdG8gcmVhZCBpdCBhcyBzb21lb25lIHdobyBzZWVzIHRoZSBj b2RlIGZvciB0aGUgZmlyc3QgdGltZSBhbmQgdGhpbmsKPiBoYXJkIHdoZXRoZXIgc2hlL2hlIHdp bGwgdW5kZXJzdGFuZCBpdC4KPiAKPiBEbyB5b3UgY2F0Y2ggbXkgZHJpZnQgbm93Pwo+IApZZXMs IGdvdCBpdC4gVGhhbmtzIGZvciB5b3VyIHZhbHVhYmxlIHRpbWUgYW5kIHBhdGllbmNlLgoKUmVn YXJkcywKTGlhbmJvCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fXwprZXhlYyBtYWlsaW5nIGxpc3QKa2V4ZWNAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8v bGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2tleGVjCg==