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 X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B610C433DF for ; Mon, 8 Jun 2020 15:42:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E80472074B for ; Mon, 8 Jun 2020 15:42:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591630967; bh=CcGUQFrKPbxqqYBdQSn7aunL0vzndo8c/yOQ5BBHLhQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=A9PaPSiQz5dfvVBNAXlYA5tnoImZYmTQxLzI42UFlku44uPbUAcIYysXIPt1sx/nW LIYWJHhWXrvPZHQ3gpiaTcNQS2gpwhbFu6jIl/2xkBMRpLESS5LCo1Ysbyocyxcq3y nsC1mIKMMrTkQgzvPJDmwlScZM/idyJLFTsDZdaw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730272AbgFHPmq (ORCPT ); Mon, 8 Jun 2020 11:42:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:50838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730237AbgFHPmp (ORCPT ); Mon, 8 Jun 2020 11:42:45 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 95938206C3; Mon, 8 Jun 2020 15:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591630964; bh=CcGUQFrKPbxqqYBdQSn7aunL0vzndo8c/yOQ5BBHLhQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gBsMPDJNjtGVl/jmnBcUHW9bDu1wu5RUrfh/1SfTLUiFY9kxCvC5tQUVcjiqdrRRg zGGKnhrKBC457xtfkyzZ/VmOelipN92/chg1ZHo2VW/x7+ZbYKfv8HrPuPDRxrpVi2 DYRPtJFy+eJEeof/DFhqUmsnS7BqRQ8/XLbheQjI= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jiJv9-001A5n-3f; Mon, 08 Jun 2020 16:42:43 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 08 Jun 2020 16:42:42 +0100 From: Marc Zyngier To: Andrew Scull Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, James Morse , Julien Thierry , Suzuki K Poulose , Mark Rutland , kernel-team@android.com Subject: Re: [PATCH v2] KVM: arm64: Remove host_cpu_context member from vcpu structure In-Reply-To: <20200608145145.GA96714@google.com> References: <20200608085657.1405730-1-maz@kernel.org> <20200608145145.GA96714@google.com> User-Agent: Roundcube Webmail/1.4.4 Message-ID: <1a00887a4af019fa83380b68afd43a29@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: ascull@google.com, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, mark.rutland@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Andrew, On 2020-06-08 15:51, Andrew Scull wrote: > On Mon, Jun 08, 2020 at 09:56:57AM +0100, Marc Zyngier wrote: >> For very long, we have kept this pointer back to the per-cpu >> host state, despite having working per-cpu accessors at EL2 >> for some time now. >> >> Recent investigations have shown that this pointer is easy >> to abuse in preemptible context, which is a sure sign that >> it would better be gone. Not to mention that a per-cpu >> pointer is faster to access at all times. > > Helps to make the references to `kvm_host_data` clearer with there now > being just one way to get to it and shows that it is scoped to the > current CPU. A good change IMO! Thanks! Can I take this as a Reviewed-by or Acked-by tag? Just let me know. Cheers, M. -- Jazz is not dead. It just smells funny...