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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0E29FC021B2 for ; Tue, 25 Feb 2025 18:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oAPMpgeQTX575axIRAvAGNwitPSc2FROHu2Kj3FuMr4=; b=RFyWye7PaGeA4GgQ2aRLEhearr A/a1BevcFo8qaNbuMKqcVGMbvpXFw5sPV4px//s4XnadOtw1nghlb+IFLEfUgAlcoX4AvJ9NxrCkA 88IvSlXO+gNr4YSN1strXOjn2Dr9SVmax0tqG4FiBqTxKRMoZoDe5byAKdoUqVHVhwa3r3gt1GzNu mA2F71/MltGSRfOLSiFmeAMMOMpFUlaBjuq24Y5yDP4y76rqzoN+OtplxO5+fstMFjda2aqldQIKW eSA0HKgrO95wV8pftJK8VQRxQufARJKYV5nWD1fXcYK3L0wUwiL6XathAA0iEoNBFnxmRD9htbg1y /YJN32JQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tn020-000000012SH-3HWE; Tue, 25 Feb 2025 18:51:48 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tmzm7-00000000xlF-3WNn for kexec@lists.infradead.org; Tue, 25 Feb 2025 18:35:24 +0000 Received: from [10.17.64.147] (unknown [131.107.1.147]) by linux.microsoft.com (Postfix) with ESMTPSA id 95078203CDDE; Tue, 25 Feb 2025 10:35:22 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 95078203CDDE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1740508523; bh=oAPMpgeQTX575axIRAvAGNwitPSc2FROHu2Kj3FuMr4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=oGQjoobXgkyRRqjRFRYg+q70hz6uhg5zsrVj8sKaiZST2hHQzUfdy24mpz723gJq3 wk6LbK9qyHkwSvnY/nWhMXJ+/pbvW5MV3urcV4jMxmRXdRhzymB2vjTgPaLEvtvDsr QnlelFhG8GfsJ2T3GYOr1XpVnIav81F+3bT3m/g4= Message-ID: <8504fd93-8fff-4fd9-8d2d-26b4e1e84bee@linux.microsoft.com> Date: Tue, 25 Feb 2025 10:35:22 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 2/7] kexec: define functions to map and unmap segments To: Baoquan He Cc: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@hansenpartnership.com, vgoyal@redhat.com, dyoung@redhat.com References: <20250218225502.747963-1-chenste@linux.microsoft.com> <20250218225502.747963-3-chenste@linux.microsoft.com> <658b52e4-a4bb-40fc-a00b-bfdb3bf15b52@linux.microsoft.com> Content-Language: en-US From: steven chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250225_103523_937889_46B00683 X-CRM114-Status: GOOD ( 19.37 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 2/24/2025 4:18 PM, Baoquan He wrote: > On 02/24/25 at 03:05pm, steven chen wrote: >> On 2/23/2025 10:14 PM, Baoquan He wrote: >>> Hi Steve, Mimi, >>> >>> On 02/18/25 at 02:54pm, steven chen wrote: >>>> Currently, the mechanism to map and unmap segments to the kimage >>>> structure is not available to the subsystems outside of kexec. This >>>> functionality is needed when IMA is allocating the memory segments >>>> during kexec 'load' operation. Implement functions to map and unmap >>>> segments to kimage. >>> I am done with the whole patchset understanding. My concern is if this >>> TPM PCRs content can be carried over through newly introduced KHO. I can >>> see that these patchset doesn't introduce too much new code changes, >>> while if many conponents need do this, kexec reboot will be patched all >>> over its body and become ugly and hard to maintain. >>> >>> Please check Mike Rapoport's v4 patchset to see if IMA can register >>> itself to KHO and do somthing during 2nd kernel init to restore those >>> TPM PCRs content to make sure all measurement logs are read correctly. >>> [PATCH v4 00/14] kexec: introduce Kexec HandOver (KHO) >>> >>> Thanks >>> Baoquan >> Hi Baoquan, >> >> For IMA, it appears that there are no current issues with TPM PCRs after a >> kernel soft reboot. > I mean using KHO to hold in 1st kernel and restore the IMA log in 2nd > kernel. > >> This patches is used to get currently missed IMA measurements during the >> kexec process copied to new kernel after the kernel soft reboot. I think >> it's ok to leave it at current location: it will be easy to maintain for >> IMA. > Yeah, but I am saying this patchset increase unnecessary code > complexity in kexec code maintaining. > >> Overall, for these patches, do you see any major blockers for kexec? >> >> If you have any specific concerns or need further details, please let me >> know. > I have no concerns for this patchset implementation itself, I saw you using > vmap to maping the possible scattered source pages smartly and taking > the mapped buffer pointers to update later duing kexec jumping. That's very > great and clever method. BUT I am concerned about the solution, if we > can make use of the existed way of KHO to implement it more simply. Could > you please do investigation? Hi Baoquan, I will conduct an investigation. Thank you for your comments. Steven