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 40E43CD8CAA for ; Tue, 9 Jun 2026 15:12:27 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=w6VKUC1VUaetCGs5JJDLFKtb8dO63YSohjJ7JwyYLsY=; b=ZDse786T0mD7zvRMfrUcc/GV8O iSyCixPXA08LmC5BR0yDY77gpiuWUYATb6JWHkfBGTmdqKfTxB+52hCUl5M+yL2pHHtwztWQzjiZy 7o12PDdfOrLytwO+i8CrRDrCXWuvaOh1wqB3CYS3cap3ZeRN5vpK/L72cPUwHboW/iZxdEnlSl99C B8f+9CCSOBcfegy7XcypYct/Kk9o7X0lJ8JZV3ipos5JAwt6Die+M2h2Wi6aXcY2Brmnw3LSqpemH 9pzMimP9fnjCIt1CveLSRK5j09vozI5ZZTvXbTft2JpBH1lpgVAP7HBFElSZDITDKnmcRp5LQfe7O GeKy1cYQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wWy7t-00000005s0M-2gJ6; Tue, 09 Jun 2026 15:12:25 +0000 Received: from mail-pl1-x632.google.com ([2607:f8b0:4864:20::632]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wWy7q-00000005s00-0425 for kexec@lists.infradead.org; Tue, 09 Jun 2026 15:12:23 +0000 Received: by mail-pl1-x632.google.com with SMTP id d9443c01a7336-2c0b1a48855so523655ad.0 for ; Tue, 09 Jun 2026 08:12:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781017941; x=1781622741; darn=lists.infradead.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=w6VKUC1VUaetCGs5JJDLFKtb8dO63YSohjJ7JwyYLsY=; b=d81tRmo7Gg3GI8TlXeOqgx3DOnUk2LPpFXRB7VeKPUsIMwRv3hPCknNKwZ4B8GqtLi ufjAmp9HIAzhcAKGAKSKoFuPjHVfA9BUlsnwJ5AoR04ltLc6DKR9sy2BYIsrbgeKaeR9 1/T/jm8nvZQhO8KAEGEj/26p8miHI68oKY70v5zOW/JJKwZvJFyt4Kk6uDtWKJJXgtdS KPXsy/LGOTn6Qkv98nx6L6wNB2JS/Jnxr5DnoPmTm1OqEJ2E6ABZ+RuybZCdaCNv2gRr Eyw5s0wwAgRbh+73l4vR/SDgAgNaybY/827irhl5am7QkVI3SlZzvCbK63qE2jvc0Cd7 wgYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781017941; x=1781622741; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=w6VKUC1VUaetCGs5JJDLFKtb8dO63YSohjJ7JwyYLsY=; b=jH2y2XlS/6VtgY7K74x/e7oQaTazRov5s18HOQWomshQNEG00rd5NVFMWy1vQABGpA FS/wxFyUn6KOSIQ3z7QKQcwLJMjguOhZrtPbysKAoQeV7qwJyp9tzb2eA/fv/vImZj2S 0QYR2Faz1EHWoFENqxT+i03Sx+NO23EkBaNIkf19PQQtkdhHu6HxnlyzKsb8FjjBHRCx aquildOj0AKsVCf4nNYGrd+ZTI6Z1ZX4CuqcMxv+M6pCpVq5QUXjk7dI9BQXs9xLRTmy QIoDRfTmd9dbiDSS+YPdClFMi/Cvd1da2BzdR0B9IJ0OmSBxxEodUBoHUShXO7q1HGjz wyDw== X-Forwarded-Encrypted: i=1; AFNElJ/+peCjSQolFvEjVqJ5vctR4uUFasQyGNz+SSgETdkdeRzzWv/YhtN6MfiI1nozrLyOtK+zfQ==@lists.infradead.org X-Gm-Message-State: AOJu0Yyx79HElm7Q4nN6aj8a3Zjc1s4x5iZ77CNwh84hdUASDtn58mOV mc2mbDc4MfRxeioSHQmYhIWcLx9IBOQ6x97ks5W7cPdj0grFm9DMhBm93LboEmgCawy5YK/ONt3 SRBAv+nsI X-Gm-Gg: Acq92OHgDc3j/vMpNEj9ttXX1+/cwYq73sJ/s3uch1aZYyLLTRd6Z75uP+t970TFgFN DluZb8tBmI0fodyLDVEnZb+ZItEpYC6qvCEHZUsWRHKhPS4Vp9C7GOkF0gE3jBuojSxkiexi2Uq knRAoJDxYuYBLLkntSTaLaD3Y1d25wJrPuS1vDMAQpeJtHRAEliE2mbJirHE6s67ese29COqTt2 x2gLHkwvEY43nRucBsQrWphh6hsTELdGHzKuMBw9k/r92dQn+k60QYlpdF7ea6EmjXum/V5VNiO hzSFZwu6R2Ke9SnLxr39lzfsK8PXJzV85tbjAoC2UsXwS+BzFRobX/ZmYDsrEXeb3uAnJaSPAjt EICgTE2FJFZIvkK9v1vbLnsWYgf+SusSmE/fvRZcf8piiXJPDgi2C3G7CAFkCQ3WcaZBxBGf/En C4orRibLBeWDHB1lkFjtg0TJY93HJFeXPG4irQJT4Z/QStvwIeyd4xiXkYrrToc4+t/X4zDW0= X-Received: by 2002:a17:903:19ed:b0:2bf:3579:cdaa with SMTP id d9443c01a7336-2c1eb942782mr7408845ad.10.1781017940616; Tue, 09 Jun 2026 08:12:20 -0700 (PDT) Received: from google.com (199.255.142.34.bc.googleusercontent.com. [34.142.255.199]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c16629d40asm208599735ad.64.2026.06.09.08.12.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2026 08:12:20 -0700 (PDT) Date: Tue, 9 Jun 2026 15:12:11 +0000 From: Pranjal Shrivastava To: Jason Gunthorpe Cc: David Matlack , kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jonathan Corbet , Josh Hilke , Leon Romanovsky , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , William Tu , Yi Liu Subject: Re: [PATCH v6 08/12] PCI: liveupdate: Inherit ACS flags in incoming preserved devices Message-ID: References: <20260522202410.3104264-1-dmatlack@google.com> <20260522202410.3104264-9-dmatlack@google.com> <20260608181640.GO1962447@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260608181640.GO1962447@nvidia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260609_081222_279332_A2FC1F80 X-CRM114-Status: GOOD ( 14.36 ) 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 Mon, Jun 08, 2026 at 03:16:40PM -0300, Jason Gunthorpe wrote: > On Mon, Jun 08, 2026 at 10:49:29AM +0000, Pranjal Shrivastava wrote: > > > My point was that a FW exploit can meddle with the bitfields of the > > ACS_CTRL to spoof and mis-report the ACS flags. > > Devices can also ignore the ACS flags. I don't think this is an area > where we should be worrying about devices being actively hostile. I'm wondering what happens if we preserve IOMMU groups across a kexec, but a switch's ACS capability is dropped or the ACS_RR bit gets cleared? The incoming kernel assumes that it's the same ACS cap from the old one Now, the incoming kernel restores the groups assuming they're still isolated, but the hardware no longer enforces it, silently allowing DMAs & breaking isolation? Thanks, Praan