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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCCD1C433F5 for ; Wed, 20 Apr 2022 17:24:44 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 26FFD40B85; Wed, 20 Apr 2022 13:24:44 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 0nPLyY-q8DDX; Wed, 20 Apr 2022 13:24:41 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D7CE940B7D; Wed, 20 Apr 2022 13:24:41 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id DD32C408AB for ; Wed, 20 Apr 2022 13:24:40 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wsnPq2qgOiC1 for ; Wed, 20 Apr 2022 13:24:39 -0400 (EDT) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id BCA4E4038C for ; Wed, 20 Apr 2022 13:24:39 -0400 (EDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7D306B81E61; Wed, 20 Apr 2022 17:24:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 399F0C385A1; Wed, 20 Apr 2022 17:24:35 +0000 (UTC) Date: Wed, 20 Apr 2022 18:24:31 +0100 From: Catalin Marinas To: Marc Zyngier Subject: Re: [PATCH v2 00/10] arm64: Add initial support for FEAT_WFxT Message-ID: References: <20220419182755.601427-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220419182755.601427-1-maz@kernel.org> Cc: kernel-team@android.com, kvm@vger.kernel.org, Joey Gouly , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Tue, Apr 19, 2022 at 07:27:45PM +0100, Marc Zyngier wrote: > A potential addition to this series would be to remove the event > generation from the counters, and rely on the timeout where it > matters (spinlocks?). Feedback welcome. I think we still need to keep the event generation around, at least for hardware bugs we don't know about. I don't think user-space rely on it though, people tend to come up with weird delays like isb ;). But yes, the WFET should be handy when it turns up in hardware. -- Catalin _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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 F3D40C433F5 for ; Wed, 20 Apr 2022 17:25:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=y9Hz5GeczAUjkcfF+xTHNCJgQO/TdP17n8QGOqVdh1o=; b=zF3JYQ/Zrh3QpN 0QYMBZ7xNIA1BRH0ORu334zfNlPqmTqON6vruN8pxxl+nMoMp7RJze7A7X1zec6gj4ZcSKrQK4Sf6 j6ON/Dw19Wq+xTp1gs6N3TAewk05ZjwikU/9yoz91/2UQDzVehYz7PFwA1dQmndgDBE1P7XqCrWEi ltnCIYM9KPFJjTRf+J1oXLz3uCZRWsL23xl3pJMgR+oq9siE5x4rmIHzZLhl0b6MovHaXc+IHRpxE BvrKNjyUcIu4mLPtAoTnUCtTXtbAz/dA65/+M//RwUT5VHLNowIEObhXS5srEOtj5EiNEmsivGHdh pZ1RSOnKf07G9St2qQMg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nhE4J-009ufc-E3; Wed, 20 Apr 2022 17:24:43 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nhE4G-009uf5-9H for linux-arm-kernel@lists.infradead.org; Wed, 20 Apr 2022 17:24:41 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7D306B81E61; Wed, 20 Apr 2022 17:24:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 399F0C385A1; Wed, 20 Apr 2022 17:24:35 +0000 (UTC) Date: Wed, 20 Apr 2022 18:24:31 +0100 From: Catalin Marinas To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Will Deacon , Mark Rutland , James Morse , Suzuki K Poulose , Alexandru Elisei , Joey Gouly , kernel-team@android.com Subject: Re: [PATCH v2 00/10] arm64: Add initial support for FEAT_WFxT Message-ID: References: <20220419182755.601427-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220419182755.601427-1-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220420_102440_504781_BB44FF38 X-CRM114-Status: GOOD ( 12.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Apr 19, 2022 at 07:27:45PM +0100, Marc Zyngier wrote: > A potential addition to this series would be to remove the event > generation from the counters, and rely on the timeout where it > matters (spinlocks?). Feedback welcome. I think we still need to keep the event generation around, at least for hardware bugs we don't know about. I don't think user-space rely on it though, people tend to come up with weird delays like isb ;). But yes, the WFET should be handy when it turns up in hardware. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEEA1C433EF for ; Wed, 20 Apr 2022 17:25:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381057AbiDTR1v (ORCPT ); Wed, 20 Apr 2022 13:27:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381010AbiDTR10 (ORCPT ); Wed, 20 Apr 2022 13:27:26 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F14374665E for ; Wed, 20 Apr 2022 10:24:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 96DC1B82115 for ; Wed, 20 Apr 2022 17:24:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 399F0C385A1; Wed, 20 Apr 2022 17:24:35 +0000 (UTC) Date: Wed, 20 Apr 2022 18:24:31 +0100 From: Catalin Marinas To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Will Deacon , Mark Rutland , James Morse , Suzuki K Poulose , Alexandru Elisei , Joey Gouly , kernel-team@android.com Subject: Re: [PATCH v2 00/10] arm64: Add initial support for FEAT_WFxT Message-ID: References: <20220419182755.601427-1-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220419182755.601427-1-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Apr 19, 2022 at 07:27:45PM +0100, Marc Zyngier wrote: > A potential addition to this series would be to remove the event > generation from the counters, and rely on the timeout where it > matters (spinlocks?). Feedback welcome. I think we still need to keep the event generation around, at least for hardware bugs we don't know about. I don't think user-space rely on it though, people tend to come up with weird delays like isb ;). But yes, the WFET should be handy when it turns up in hardware. -- Catalin