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 B1FCDC04A94 for ; Wed, 9 Aug 2023 09:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231818AbjHIJKo (ORCPT ); Wed, 9 Aug 2023 05:10:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229815AbjHIJKn (ORCPT ); Wed, 9 Aug 2023 05:10:43 -0400 X-Greylist: delayed 2723 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 09 Aug 2023 02:10:41 PDT Received: from out-81.mta0.migadu.com (out-81.mta0.migadu.com [IPv6:2001:41d0:1004:224b::51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB5E71FD0 for ; Wed, 9 Aug 2023 02:10:41 -0700 (PDT) Date: Wed, 9 Aug 2023 09:10:33 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1691572240; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mvmzvKOGcM7VTd90ZNc4xMJrUWrhIk71OKZHdX1ecXM=; b=qrezTWI5AElJZqV9qQGcT9+Kg1Sv+qGaGp0ABG0ROC2hAq8H45AlVEdjXZmLHcWdvrAN3v UzgLZj9d3z52lNjfEviNP8FCivMcqGZikDTWDs5h5Ill5r0bZfDRxCFUdB+utjW4CZS/M9 zYb9t9t6JFETPi3apcQaXR40eklcy1Y= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Marc Zyngier Cc: Huang Shijie , james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, pbonzini@redhat.com, peterz@infradead.org, ingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-perf-users@vger.kernel.org, patches@amperecomputing.com, zwang@amperecomputing.com Subject: Re: [PATCH] perf/core: fix the bug in the event multiplexing Message-ID: References: <20230809013953.7692-1-shijie@os.amperecomputing.com> <864jl8ha8y.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <864jl8ha8y.wl-maz@kernel.org> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Wed, Aug 09, 2023 at 09:48:29AM +0100, Marc Zyngier wrote: [...] > Another question is how the same thing is handled on x86? Maybe they > don't suffer from this problem thanks to specific architectural > features, but it'd be good to find out, as this may guide the > implementation in a different way. I'm pretty sure the bug here is arm64 specific. x86 (at least on intel) fetches the guest PMU context from the perf driver w/ irqs disabled immediately before entering the guest (see atomic_switch_perf_msrs()). -- Thanks, Oliver