From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 545E74519A5; Sat, 3 Oct 2026 16:09:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791043799; cv=none; b=awQo46Nk+vpCLTWrgAB+pnXFVu6dA1c4CFJJ/dDGrdKtaVtEfQH5BHwrsoy3LlbxGZ+LIB+cVW032ZuWzMPTPkBxNq5rnd5NIKHWRwGASFJRXvfPt/X8CLM1egD0Dkw9yMX2LENJCELA5DH1p7EZzgGHBLEQoS711nx9reA/08s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791043799; c=relaxed/simple; bh=q7bSHdUt2NW8NRbyiyELYRSZ5SoLcldxJipAr8d+MIo=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=CNHX2yv9+EiD3WlslnplugGsHPBHbypI139CZNKQKcsVNCVHIxNiipA7kPJ6cjVHQkFv0GKO3mUUHtBy/+dRvVJQqqFnE3djrPO+xHksKccbdgBraRcXqJNjBJgADovIbd54KNUj+fnKp91zxigoCMYi6w4/2o/FfN1wh3mm2bw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oN/nWJYY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oN/nWJYY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7716D1F0089B; Sat, 3 Oct 2026 16:09:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791043784; bh=8NWGwlQkszgpeDaU/7RVwfUPvUd34G5HRT8qHpyUbDE=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=oN/nWJYYAx1Fal5a4qVGc2kJsll2CIviWg+5K5nj+kDGFj0nnoXUNpamtpQP44Bbv Owc98bzItftGpzLvIC0emFoONYsGsnDdqg6KlrEV/pxG5/9YUvXRsHiHojsyuyuE2n Zh+HmCUDKwpyu2l9h+464MN4SZ4C4bHD3UYQ7xh6kFk+P0wC4vjtmXL/VnrkGNn18s 1wliJsxW2uhc/ep898c3KimWIJP3fQrrlIFFjJk6VR02piT9P9+HrC5ppZOHgQSgBG VWYy/MsrFIB+vv3o6NZO76dGBj/N85tPHfMdhXqefBfo9lDaFag1yfTClIv5Gf+E0v ZoTM+Q7mortCw== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1xD2Iw-0000000GZHf-1NT7; Sat, 03 Oct 2026 16:09:42 +0000 Date: Sat, 03 Oct 2026 17:12:50 +0100 Message-ID: <87mrsu3gql.wl-maz@kernel.org> From: Marc Zyngier To: Kristina =?UTF-8?B?TWFydMWhZW5rbw==?= Cc: linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, kvmarm@lists.linux.dev, linux-efi@vger.kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Ryan Roberts , David Hildenbrand , Lorenzo Stoakes , Linu Cherian , Anshuman Khandual , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Ard Biesheuvel , Ilias Apalodimas Subject: Re: [RFC 00/12] arm64: Add support for TLBI domains In-Reply-To: <20261001110655.461473-1-kristina.martsenko@arm.com> References: <20261001110655.461473-1-kristina.martsenko@arm.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/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kristina.martsenko@arm.com, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, kvmarm@lists.linux.dev, linux-efi@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, ryan.roberts@arm.com, david@kernel.org, ljs@kernel.org, linu.cherian@arm.com, anshuman.khandual@arm.com, lpieralisi@kernel.org, guohanjun@huawei.com, sudeep.holla@kernel.org, oupton@kernel.org, fuad.tabba@linux.dev, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, ardb@kernel.org, ilias.apalodimas@linaro.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Hi Kristina, On Thu, 01 Oct 2026 12:06:43 +0100, Kristina Mart=C5=A1enko wrote: [...] > * It's also possible to use TLBI domains to limit a KVM guest's TLB > invalidations to CPUs where the guest has run. I'll try to include th= at in > the next version. This series only disables domains for guests. My take on this is that just like MPAM, it makes little sense to expose this to guests. As long as the L0 hypervisor has the means that to scope TLBIs to the relevant domains (subset of CPUs to start with, but hopefully SMMUs eventually), we're good. > * With this series a long-running process may eventually run on all CPU= s and > just issue broadcast TLBIs. It may be worth periodically reducing the= set > of CPUs but it's not clear when. I had a think about that some time ago, and thought that you were sure to be sub-optimal when the number of CPUs you have run on is greater than the number of threads in your process. But I'm sure there are better heuristics! ;-) Thanks, M. --=20 Jazz isn't dead. It just smells funny.