From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f68.google.com (mail-qv1-f68.google.com [209.85.219.68]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB9052DE715 for ; Mon, 2 Feb 2026 23:45:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.68 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770075943; cv=none; b=JVbMHXnyqUCnA7BQiJ9Lgw/nuqKJiOSuGIwlvIA0PLWjdA+at3HdEdCNlVFjzvpNUDsmzN9oRuYeOSdoie61mLe0NwhlRn33LDKqFZ/ueUhVDolZYnAlfWyevmMlItXfP7K5CUhsoIR8XtPe6KlZf5aQKCwzHvjvLSjeeYNWTd4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770075943; c=relaxed/simple; bh=NYIQ8k0J36Z+pqu7eLVLT+nA4jM07QuVSOcSQOhWSw8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oWwmYqz/hWs1ip2DQazvgg6r1pgAF7XbwAO8WcaxvsfJzi0+G6LjvEB/6aEzE20QZiVP3T2WYJ3wfzeE7rkm9xwbf98gusGRAkpKUEefmxjYeJl+q2fwk+sb8hJT/N7lpGvK4pcyNpU1JSY/ogGisaqii2ZDvzBVVVjNDAnUsWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=j5PaAb0T; arc=none smtp.client-ip=209.85.219.68 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="j5PaAb0T" Received: by mail-qv1-f68.google.com with SMTP id 6a1803df08f44-89473f15ed8so45327986d6.2 for ; Mon, 02 Feb 2026 15:45:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1770075941; x=1770680741; darn=lists.linux.dev; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=p2Lhp0szvkgF9ZK/gTcTHYbmH9trOSyqBk9Fq52/yQY=; b=j5PaAb0T9EYnE2xYgilF7lQcieWgBouwKftgFDw5I42iqmxxHPoUU2UgaXdifHr9oX JWxsyYbcF96MTj0yABJAKC+Nf44fn8dW755rQoPV7DvnmepSfj7829xj6P1hkMFerUwg ym1pCpipcNnFyenKKK7XYvVo01r1x6auKPSx+D7MdhBn5cfiUKqXk9I1JSwpeYTVGfmj ZmkcooLAqNq2/t0FgwTQEMlxJU/lb+IlYp/QCPfxRjpsE7JcKMOq/l+E+SXnRu000Ji3 78qhpVjsJYnhbf0t/n1idENKELHgTgAX6Wvz6Ch5q8cY+5x5dxsd5YjxsnbIM4I9gHEh iKMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770075941; x=1770680741; h=in-reply-to:content-transfer-encoding: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=p2Lhp0szvkgF9ZK/gTcTHYbmH9trOSyqBk9Fq52/yQY=; b=VZA7jow40Mukie6P0XY/SSDDPYgDY2Aln33fbPP/RvVendroNK9yKdOvpGe3OU4DnX j1BUWQnbmA4yAkrOMnaWIj6ZMtddM5Om6fjWVQUT0GqU5+zoxpRxOKbSt4HDGlyLp31B MSftso0z3qN9jUPSWrzQbj3b/pHtXWeIGxLj8rfMoEkWmyaaQL2odlunemSAyxqsXxxK rqd3pVGmc5F/U0PZSnjKlNB+9et/igwdg+AnzNgmcAT4BolJ3NJBpT6g8PGbNYgOZzON RnfvZzSZMI3w/JqmQQEQlBrtFuqtFNB34AXa/VYAUix0PWYFfqJxnohVWC+mSdEg2ogh WRvQ== X-Forwarded-Encrypted: i=1; AJvYcCXi7OntTbkvNvFEp1HMJ+25tGKH6uCfStpyvCkVW+J/RhBNLuxzBtq+us2gnVHYMML8MpqC4Q==@lists.linux.dev X-Gm-Message-State: AOJu0Yyshk3PCKMw5QFPXSZWg1QlEtTzatKJKbahNx+YCrSVw2wv8UEb wJP0ASYSSOcGTnPB0M4V1S9pLluC6IDUae0eTEqumYRVUiN5HAdjQMgCntmSbrnys5g= X-Gm-Gg: AZuq6aKKMYjw/cCEeBdExNlXI2hkHV34V6I2tLh16cmLVNvP82RK9Tzo18StE2Zs9ls abgAesztpibi1cfmTL00Iv8tXSh9InFOtK3xPQXrfyuEpj/O/4w4yrRU1FlHzYctOPizjD6yyDa +z+f/SNNtq2dwRIsRVYf1AFkWQhInYpd2zJPQiX1KLIE6UWBjivKxVIsHwTObkXrIMsQilDM7OF bMIcRtxvf3d0JKcmDVS0JGr15W91lDfEBnneDjGE5OjjATCQK2BgXQFkQSwbgHadxCFDfRAufaB gdQ63cOBd6K60ENR+BSm3poTjAEBuJdgLKsvRGCgmo9Yi6GVzDpX84iEkqw2FM5BA/iZ0vQ00zv bbsILwmnuzbGyJVjW8M1T8i9/KwkdlRWO1ZynwTFWA6rD3bdODXKCxqQ6HSG6wQdFVRCe4s7447 RWsauNsSZRjAsTbdwxqNAiYZ6tW5Hcs1pZ0cmTBecc7GQmYgRhTwUgsbZZV7wDoDCR7+8= X-Received: by 2002:a05:6214:1244:b0:87c:2967:fd32 with SMTP id 6a1803df08f44-894e9f86526mr176075016d6.22.1770075940655; Mon, 02 Feb 2026 15:45:40 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-112-119.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.112.119]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-894d36c448esm124994316d6.14.2026.02.02.15.45.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Feb 2026 15:45:40 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vn3bv-0000000GNrK-37Et; Mon, 02 Feb 2026 19:45:39 -0400 Date: Mon, 2 Feb 2026 19:45:39 -0400 From: Jason Gunthorpe To: David Matlack Cc: Samiullah Khawaja , David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Pasha Tatashin , iommu@lists.linux.dev, Robin Murphy , Pratyush Yadav , Kevin Tian , Alex Williamson , linux-kernel@vger.kernel.org, Saeed Mahameed , Adithya Jayachandran , Parav Pandit , Leon Romanovsky , William Tu , Vipin Sharma , YiFei Zhu , Chris Li , praan@google.com Subject: Re: [RFC PATCH v2 00/32] Add live update state preservation Message-ID: <20260202234539.GN2328995@ziepe.ca> References: <20251202230303.1017519-1-skhawaja@google.com> <20260128195943.GY1641016@ziepe.ca> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Feb 02, 2026 at 10:45:48PM +0000, David Matlack wrote: > On 2026-01-28 05:11 PM, Samiullah Khawaja wrote: > > On Wed, Jan 28, 2026 at 11:59 AM Jason Gunthorpe wrote: > > > On Tue, Dec 02, 2025 at 11:02:30PM +0000, Samiullah Khawaja wrote: > > > > Start off by just making the successor kernel fail to accept any > > > drivers at all because the iommu_domain was preserved. ie restore the > > > domain and set it as the default_domain and then fail in > > > iommu_device_use_default_domain() and related functions. > > > > Right. In this model, the device would remain unusable after > > liveupdate as you cannot do session finish. So the only way to recover > > would be to do a proper reboot. But I think this is a great > > intermediate step. > > This will break the new selftest vfio_pci_liveupdate_kexec_test that is > added in the vfio cdev series: > > https://lore.kernel.org/kvm/20260129212510.967611-19-dmatlack@google.com/ > https://lore.kernel.org/kvm/20260129212510.967611-23-dmatlack@google.com/ > > And having to reboot a machine back to life after every Live Update will > be a painful for everyone working on VFIO, PCI, and IOMMU Live Update > support. I expect it to be under a config protection and people will simply turn it off. Jason