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 1BF46ECAAD5 for ; Tue, 6 Sep 2022 13:54:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 70D2C8028B; Tue, 6 Sep 2022 09:54:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6BCA080224; Tue, 6 Sep 2022 09:54:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 585008028B; Tue, 6 Sep 2022 09:54:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 4974980224 for ; Tue, 6 Sep 2022 09:54:43 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 1407D12185D for ; Tue, 6 Sep 2022 13:54:43 +0000 (UTC) X-FDA: 79881806046.13.B98480F Received: from mail-yb1-f182.google.com (mail-yb1-f182.google.com [209.85.219.182]) by imf11.hostedemail.com (Postfix) with ESMTP id B9F294006C for ; Tue, 6 Sep 2022 13:54:42 +0000 (UTC) Received: by mail-yb1-f182.google.com with SMTP id g5so16884729ybg.11 for ; Tue, 06 Sep 2022 06:54:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=itCXU38GNPssCt/WSnoeX0ePqT6vjs+McfV7VfLaXm0=; b=RzruAzofCMQISZ7x90frSvdR83WhvBYVnd/FIbkqRMYnbBjNIgunhHzImKxDheGcpL OmES4oqH+U6hqJ0648JvYJZ5FJ+XnQkpvpnXYgB/FZ2GHPLpJQ0QN43GPHin/l08XpS+ yD6NvtTAv9ASEpDarkUwqQ7XPSv/6B2AnCvhwYXuozzv1drCaTJQx0wM6RSbsfiLp8vS hTI5vh/Nq7+qwYVeRC0+Wi0CLMRGz4IGkt+KOWpO0jt1yWsiz3o5zKR+ITp0n8AwZI8N LAlFx6LxeWUT6fQvRdtU5fvX6dnqt4hhTbzzQFbyflygaMAJQ3a1DrvR1p63UgA9p9fv B9HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=itCXU38GNPssCt/WSnoeX0ePqT6vjs+McfV7VfLaXm0=; b=NsH6VS9X3Ss2dR6nKBKertvzNM3dJXpWE92kRiMISYRD5yPrTN0NniI2hgwz44e07w DnP3j8dGqq3S1ZmSk4fZrSOSideneWu4MunIxIhCcPbBjXN3A4alZKR1TJOcornN1Qdl twwhiuhR5k6dY88D+5C/HLBN7i3TVxtVa+2UqvfddQXymIc/BfMoxvllSMQbiiJk9YJu rGL+2ZyVhMF5+gUpcML/P69fvnM8YEUPBClV4LIPH2hssrPL3rtxIaPTaNI1QRdJ6jlu ATcziVd1zWxwjsZYV9g+1CN4RSpYGNcKunYV+dT7CEbHqw5sbuW+KfpV8IN9sRvWmBdV ZWMg== X-Gm-Message-State: ACgBeo3zJHS9xOGdxDmSGNIiQIVQK1QaXxWV0QUW54JAhYwUw2+NKBoO 2b6Z350TMje1rTyJqJzPLkqNBfLehemvy0IofHhrQA== X-Google-Smtp-Source: AA6agR6QNbWksDmoi7tCjaXWjvMyjPy9pFFuRtJzEHIb64zO9pawVP7ef2xQZqgbZnq01U/6FcMtKbhZEmVMfTewxmY= X-Received: by 2002:a25:83d2:0:b0:696:1071:1a01 with SMTP id v18-20020a2583d2000000b0069610711a01mr37353558ybm.335.1662472481680; Tue, 06 Sep 2022 06:54:41 -0700 (PDT) MIME-Version: 1.0 References: <0ecb0a4781be933fcadeb56a85070818ef3566e7.1655761627.git.ashish.kalra@amd.com> In-Reply-To: From: Marc Orr Date: Tue, 6 Sep 2022 06:54:30 -0700 Message-ID: Subject: Re: [PATCH Part2 v6 09/49] x86/fault: Add support to handle the RMP fault for user address To: Jarkko Sakkinen Cc: Borislav Petkov , Ashish Kalra , x86 , LKML , kvm list , linux-coco@lists.linux.dev, Linux Memory Management List , Linux Crypto Mailing List , Thomas Gleixner , Ingo Molnar , Joerg Roedel , "Lendacky, Thomas" , "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 , "Roth, Michael" , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , Tony Luck , Sathyanarayanan Kuppuswamy , Alper Gun , "Dr . David Alan Gilbert" Content-Type: text/plain; charset="UTF-8" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662472482; a=rsa-sha256; cv=none; b=mKxzMz3hyUkt+h0y4TBx9RLMgXJNGcz3JFtqQ0wdXNw8VzdVUnhN1NiKY0Ski5iO7wMSZ6 Dt9KqJmlqmGbNBfZBxa8U6QFl37eQGrBcPWX+JhmxJkKH5GaKPlfaHmCG2Kwi7B9aqmvZ0 87ZOFx7u+D7fI5tGME0WGjRxSDWoOIo= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RzruAzof; spf=pass (imf11.hostedemail.com: domain of marcorr@google.com designates 209.85.219.182 as permitted sender) smtp.mailfrom=marcorr@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662472482; h=from:from:sender: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:dkim-signature; bh=itCXU38GNPssCt/WSnoeX0ePqT6vjs+McfV7VfLaXm0=; b=pC2sTmNLXcpdqtVC0xa1HSjcv6QJlcQ5iyuKGyHLCYYoYGYTeZDsynUdcs2QQ9zoz2gWHw Ofn7GQXOfkPp/Gk+xum3Ck0RPncSIimdZX0q2Um+uaAX8FVCRUnBQ918HzpnewGqi0RbEf kKO/gUUXQHUM8t2h+zM9a0HoXf1jiRw= X-Stat-Signature: s3k1inbqya9fii478xd5hycda5rweb1a X-Rspamd-Queue-Id: B9F294006C X-Rspam-User: Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RzruAzof; spf=pass (imf11.hostedemail.com: domain of marcorr@google.com designates 209.85.219.182 as permitted sender) smtp.mailfrom=marcorr@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam08 X-HE-Tag: 1662472482-642445 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 Tue, Sep 6, 2022 at 3:25 AM Jarkko Sakkinen wrote: > > On Tue, Aug 09, 2022 at 06:55:43PM +0200, Borislav Petkov wrote: > > On Mon, Jun 20, 2022 at 11:03:43PM +0000, Ashish Kalra wrote: > > > + pfn = pte_pfn(*pte); > > > + > > > + /* If its large page then calculte the fault pfn */ > > > + if (level > PG_LEVEL_4K) { > > > + unsigned long mask; > > > + > > > + mask = pages_per_hpage(level) - pages_per_hpage(level - 1); > > > + pfn |= (address >> PAGE_SHIFT) & mask; > > > > Oh boy, this is unnecessarily complicated. Isn't this > > > > pfn |= pud_index(address); > > > > or > > pfn |= pmd_index(address); > > I played with this a bit and ended up with > > pfn = pte_pfn(*pte) | PFN_DOWN(address & page_level_mask(level - 1)); > > Unless I got something terribly wrong, this should do the > same (see the attached patch) as the existing calculations. Actually, I don't think they're the same. I think Jarkko's version is correct. Specifically: - For level = PG_LEVEL_2M they're the same. - For level = PG_LEVEL_1G: The current code calculates a garbage mask: mask = pages_per_hpage(level) - pages_per_hpage(level - 1); translates to: >>> hex(262144 - 512) '0x3fe00' But I believe Jarkko's version calculates the correct mask (below), incorporating all 18 offset bits into the 1G page. >>> hex(262144 -1) '0x3ffff'