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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 73090C5DF60 for ; Fri, 8 Nov 2019 07:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BE9E206BA for ; Fri, 8 Nov 2019 07:54:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="JNQXdFPU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729969AbfKHHyW (ORCPT ); Fri, 8 Nov 2019 02:54:22 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:37110 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725886AbfKHHyW (ORCPT ); Fri, 8 Nov 2019 02:54:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Mime-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=m7F4yeQFXzq24Xcdu21wGwru8kTugv4RivTLmZPl0o0=; b=JNQXdFPUQia7yG1YDFERMtCUt HrNp7z2hHCQdQ+CYR/ORZH48MgMkqQBxQh3/ChhoDSZUNqiWXaO/PBccUZFI0sGuRAJnoXcNjHPA4 MrrYkfFkVM8JD085ZjjOCDwi8kYOCyZFH6c1aKIrP/BFAB/sbfn4GUlWIYrFBUxq+qGlvPe2A/s6q l+8Z/f5j7xj3LWdbKcMrfdHjTAjSuUE1Gq0cknJyfDKSqOct/O6OtDTqOSFFMD3yXrRgG4RQp8lrW A3BaYZ4YSt8PECXv1RKbFCchrZe4gfWIIt2dT3r/DQyVziFiUqVLDEIxen+FDs0gF+B3niDXGXxKL 1lFeeNtEw==; Received: from [54.239.6.185] (helo=freeip.amazon.com) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iSz64-00010Q-8W; Fri, 08 Nov 2019 07:54:20 +0000 Message-ID: <1672a5861c82c2e3c0c54b5311fd413a8eee5e64.camel@infradead.org> Subject: Re: [PATCH] intel-iommu: Turn off translations at shutdown From: David Woodhouse To: Deepa Dinamani , joro@8bytes.org, linux-kernel@vger.kernel.org Cc: iommu@lists.linux-foundation.org, Jason.Zeng@intel.com, "Tian, Kevin" Date: Fri, 08 Nov 2019 07:54:17 +0000 In-Reply-To: <20191107205914.10611-1-deepa.kernel@gmail.com> References: <20191107205914.10611-1-deepa.kernel@gmail.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-NB4SzEZqNjpYNZDwWzUK" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-NB4SzEZqNjpYNZDwWzUK Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2019-11-07 at 12:59 -0800, Deepa Dinamani wrote: > The intel-iommu driver assumes that the iommu state is > cleaned up at the start of the new kernel. > But, when we try to kexec boot something other than the > Linux kernel, the cleanup cannot be relied upon. > Hence, cleanup before we go down for reboot. >=20 > Keeping the cleanup at initialization also, in case BIOS > leaves the IOMMU enabled. >=20 > I considered turning off iommu only during kexec reboot, > but a clean shutdown seems always a good idea. But if > someone wants to make it conditional, we can do that. This is going to break things for the VMM live update scheme that Jason presented at KVM Forum, isn't it? In that case we rely on the IOMMU still operating during the transition. --=-NB4SzEZqNjpYNZDwWzUK Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCECow ggUcMIIEBKADAgECAhEA4rtJSHkq7AnpxKUY8ZlYZjANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTkwMTAyMDAwMDAwWhcNMjIwMTAxMjM1 OTU5WjAkMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZyYWRlYWQub3JnMIIBIjANBgkqhkiG9w0B AQEFAAOCAQ8AMIIBCgKCAQEAsv3wObLTCbUA7GJqKj9vHGf+Fa+tpkO+ZRVve9EpNsMsfXhvFpb8 RgL8vD+L133wK6csYoDU7zKiAo92FMUWaY1Hy6HqvVr9oevfTV3xhB5rQO1RHJoAfkvhy+wpjo7Q cXuzkOpibq2YurVStHAiGqAOMGMXhcVGqPuGhcVcVzVUjsvEzAV9Po9K2rpZ52FE4rDkpDK1pBK+ 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