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 DB21AC433EF for ; Tue, 8 Mar 2022 09:34:40 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2F6C349E5F; Tue, 8 Mar 2022 04:34:40 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, body has been altered) header.i=@kernel.org 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 ruuh8s-sLlfV; Tue, 8 Mar 2022 04:34:36 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id DC16749EC4; Tue, 8 Mar 2022 04:34:36 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 3B11349E45 for ; Tue, 8 Mar 2022 04:34:35 -0500 (EST) 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 3V-z6sAUEfru for ; Tue, 8 Mar 2022 04:34:32 -0500 (EST) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id EC9B449E42 for ; Tue, 8 Mar 2022 04:34:31 -0500 (EST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 0F56E6130E; Tue, 8 Mar 2022 09:34:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76566C340EB; Tue, 8 Mar 2022 09:34:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646732070; bh=4vS2F2+fp/NgFdOgzPKFi9Fq/69UuhAW8b1DAEs4zDY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XN27WXQZExjGEqYmCzTtfDQX4tApCXE5miabdUto0Gt3YyDAxbUl34g2cY42576gT 0r0VgtEsT/uE+yVooejm2YwOJ1hu8KW1YehtKRZgjloNdMTjCCm20I5Esjn0MDn09w EoNwudcRYq8XWZnqx+vaGR0oTjkYO2sxJGX6l8MiQfqIu2yWQkoNrs5pQ+uhd6rCWV BfqYVZNEr4konsxjG83HaB1kelgvaCwN9+gUDJXRYPAqqgTGIDJNCMUqHyeFizojS/ y1j3zEVtZg8WnQMkSkYLkZkdH29JPkJg3MEiC6O4PioyoeAwq15DRbLHpAQRJBCso1 eUHEwxL0kWhRg== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nRWEe-00D17M-8c; Tue, 08 Mar 2022 09:34:28 +0000 Date: Tue, 08 Mar 2022 09:34:27 +0000 Message-ID: <871qzc23fg.wl-maz@kernel.org> From: Marc Zyngier To: Eugene Huang Subject: Re: Timer delays in VM In-Reply-To: References: <667c9f084b2d38725369de60daef6d58@misterjones.org> <87wnhc6cef.wl-maz@kernel.org> <87v8wv14iq.wl-maz@kernel.org> 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/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: eugeneh@nvidia.com, kvmarm@lists.cs.columbia.edu X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: "kvmarm@lists.cs.columbia.edu" 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 Hi Eugene, On Tue, 08 Mar 2022 07:50:50 +0000, Eugene Huang wrote: > > Hi Marc, > > Looks like to effectively troubleshoot, we need to upgrade our guest > kernel to the latest version 5.17. I have these questions. > > 1. Can you please point out the kernel source that programs the arm > virtual timer? drivers/clocksource/arm_arch_timer.c > 2. is The Generic Timer section in ARM Architecture Reference Manual > ARMv8 the correct reference that we should refer to? Yes, section D7. You'll also need the GIC specifications (IHI0069H in your case), because you can't really understand how KVM works without looking at both. > 3. From the kernel community point of view, which kernel in the > guest is the better - the Ubuntu one or the upstream one? Upstream. In general, distro kernels are only a nuisance when debugging things. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm