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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 CBC3BC433E1 for ; Wed, 22 Jul 2020 16:21:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 839742065F for ; Wed, 22 Jul 2020 16:21:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="UcMcUqZG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 839742065F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2F7C86B0005; Wed, 22 Jul 2020 12:21:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A85B6B0006; Wed, 22 Jul 2020 12:21:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 197666B0007; Wed, 22 Jul 2020 12:21:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id 05D2F6B0005 for ; Wed, 22 Jul 2020 12:21:59 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B0BBE1072A646 for ; Wed, 22 Jul 2020 16:21:58 +0000 (UTC) X-FDA: 77066228316.07.limit50_5a056c426f37 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 8115918512152 for ; Wed, 22 Jul 2020 16:21:58 +0000 (UTC) X-HE-Tag: limit50_5a056c426f37 X-Filterd-Recvd-Size: 3234 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Wed, 22 Jul 2020 16:21:57 +0000 (UTC) Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BEF42208E4 for ; Wed, 22 Jul 2020 16:21:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595434917; bh=NnybZoElq3+0KYwoEu4w7pBb4jnYvQOexyS5ysvraSE=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=UcMcUqZGs3A/zHint+yQtia7Uf3Fb8yRh4OyYW73633eFDF8vcz9eD7uDnKQ/c0cu yoA7jR0qN1gN5YgaAVpozWehWHO7y/XScv8pB/dupzQgn5vR4+tU+XPdcM9ijeUk8u 8oa5kAzlA1/+LXQc6uLgnZdv5H6c3AhKs2JE2T38= Received: by mail-wr1-f45.google.com with SMTP id s10so2465810wrw.12 for ; Wed, 22 Jul 2020 09:21:56 -0700 (PDT) X-Gm-Message-State: AOAM533x1SlcHu57aXbNOTBsFmOFtPMvi3ypQJytjweFD2+8RFNuphYE sr38p78gt5zYzN4CYkSPRHfVYgVDvtxv2JW4iTvYCg== X-Google-Smtp-Source: ABdhPJyEetM5mfaR+krsbN1VbThAmtrGRoGcIADpoq0lN9rBpz6OtbXdH4MYYDkEz8tY7NVo/wEe+Jv+iOx79Efg25I= X-Received: by 2002:adf:e482:: with SMTP id i2mr296828wrm.75.1595434915303; Wed, 22 Jul 2020 09:21:55 -0700 (PDT) MIME-Version: 1.0 References: <20200717072056.73134-1-ira.weiny@intel.com> <20200717072056.73134-18-ira.weiny@intel.com> In-Reply-To: <20200717072056.73134-18-ira.weiny@intel.com> From: Andy Lutomirski Date: Wed, 22 Jul 2020 09:21:43 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH RFC V2 17/17] x86/entry: Preserve PKRS MSR across exceptions To: Weiny Ira Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra , Dave Hansen , X86 ML , Dan Williams , Vishal Verma , Andrew Morton , Fenghua Yu , "open list:DOCUMENTATION" , LKML , linux-nvdimm , Linux FS Devel , Linux-MM , "open list:KERNEL SELFTEST FRAMEWORK" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 8115918512152 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 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 Fri, Jul 17, 2020 at 12:21 AM wrote: > > From: Ira Weiny > > The PKRS MSR is not managed by XSAVE. It is already preserved through a > context switch but this support leaves exception handling code open to > memory accesses which the interrupted process has allowed. > > Close this hole by preserve the current task's PKRS MSR, reset the PKRS > MSR value on exception entry, and then restore the state on exception > exit. Should this live in pt_regs? --Andy