From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 717E43207 for ; Fri, 18 Oct 2024 13:17:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729257440; cv=none; b=abaewkxamCmSCyxvyVXgFxtqzVQcenuJsqBRybToticKd9wNPsWMuAOAQ7qV2rFTch7jGUkSXW/XQ5BqYo6DZ5Iub1F/iNCfnATP0tO523wyFVXUya6A0MD5ipUVzNyZwLWj6FKXm1EPaRgWrVR31CYDAyAZmdpc484Ax9JRzYs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729257440; c=relaxed/simple; bh=L5rawYHNcZfm3YbcBMmna12iVHaxrHfAG7LJCWDc6cQ=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=BG5J/QRLhSoc8OM4kvR2KgJsJmC723TnXcKInJ966qAoRk4Rf89H4G97g2yTqSNIwGxqKPBkXC/4rW+axS9lcorCHmySyyJglEelVubB62X6/bJudqf1zak9VDYcgB3PPVkc8kaQPFZCG05j283UHmSYl1EXSzQnIzU9ZjHTHJc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fv8jKNkX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fv8jKNkX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEB7FC4CEC3; Fri, 18 Oct 2024 13:17:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729257440; bh=L5rawYHNcZfm3YbcBMmna12iVHaxrHfAG7LJCWDc6cQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fv8jKNkXK2ebXxMUI1BhJYegQV/SBzMvzO6mN5slJUvv2zDSyvdNtqK6iClymVi04 vrgyIWwJqDOMA/92ltJPrG7UpnxLOBgvEcli91r1J4aCdUbCVVX1TUmkhykXIyHPxo vtrX5CIvce0tLFx0nYu3XLy7oPA92/+MDkF7onqVLFZOFH3NV4DBGb91KY95ylbS4e tmXvMEvdFoU3WqRYBwj/6U5yN1xQweiuAcUfpP3B7++k371U3r0/gzyBq88GYlpksh HtEuysFESVt3Nca5GUGCq5wWVcvGWnfkQolLsBNsZmy7B2Kp71CB17vk9p41nU87gd PFsbYoMb01ZpA== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1t1mqz-004miX-PS; Fri, 18 Oct 2024 14:17:17 +0100 Date: Fri, 18 Oct 2024 14:17:17 +0100 Message-ID: <86frot4kki.wl-maz@kernel.org> From: Marc Zyngier To: eric.auger@redhat.com Cc: Cornelia Huck , Shameerali Kolothum Thodi , Oliver Upton , "kvmarm@lists.linux.dev" , "catalin.marinas@arm.com" , "will@kernel.org" , "mark.rutland@arm.com" , yuzenghui , "Wangzhou (B)" , jiangkunkun , Jonathan Cameron , Anthony Jebson , "linux-arm-kernel@lists.infradead.org" , Linuxarm Subject: Re: [RFC PATCH 0/6] KVM: arm64: Errata management for VM Live migration In-Reply-To: <7df21c56-0b07-4112-839e-ef90c5999fcd@redhat.com> References: <20241011075053.80540-1-shameerali.kolothum.thodi@huawei.com> <86jzef53iz.wl-maz@kernel.org> <3f4469c49625413f9ab2c224d0d3fbea@huawei.com> <86ikty6f1b.wl-maz@kernel.org> <08261a41b9644f5ab49063824e4060c3@huawei.com> <87bjziraou.fsf@redhat.com> <7df21c56-0b07-4112-839e-ef90c5999fcd@redhat.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: eric.auger@redhat.com, cohuck@redhat.com, shameerali.kolothum.thodi@huawei.com, oliver.upton@linux.dev, kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, yuzenghui@huawei.com, wangzhou1@hisilicon.com, jiangkunkun@huawei.com, jonathan.cameron@huawei.com, anthony.jebson@huawei.com, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Thu, 17 Oct 2024 18:16:04 +0100, Eric Auger wrote: > > Hi Shameer, > > On 10/17/24 17:49, Cornelia Huck wrote: > > Speaking of QEMU: Do you maybe already have some prototype code that > > tries to do something with the setup here? (I don't think QEMU currently > > mucks around with MIDR and friends when running with KVM; I wonder what > > it should provide to the guest and if it should care to set something as > > a base level that gives guests not using the hypercall a chance to work > > properly.) > > > As discussed during the KVM forum we are working on a qemu integration > for writable ID regs. The first goal is to be able to specialize the > host passthrough model (custom host model). Maybe this will trigger more > discussions on named models too. This is complementary to the > MIDR/REVIDR problematic and I hope we will be able to consolidate our > works at some point. Complementary to the MIDR/REVIDR work, I would also like to make MIDR/REVIDR writable when this scheme is available. Ideally reporting a synthetic CPU description (with MIDR_EL1.Implementer returning 0, and the rest being VMM-specific, but with a clear definition for the IMPDEF fields so that we can version the ABI). Thoughts? M. -- Without deviation from the norm, progress is not possible.