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 2600BCF8844 for ; Thu, 20 Nov 2025 11:36:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TPlzmXt4DNVBdqLVvxiBIWu8Rl4FZ4bDuiyypGx7MuQ=; b=PpfrRsC+z6dUG1Ub5p6ZuFLdIG wYd41v5VHSG+jVy4tmz6V3hAJBmflYNl0MA8j73fF5wNejR60kgdYStwHMNfS3KlJhdk+efkAC4Q4 M/da8aSmI9rlpnTHoeamvLC36eCRcSkNATT7cKY8rfJzXRNGhYe3dH1bFLu0G1tUMznvzXOzq8po3 QdmuGg17it1UqbX0Pbfu30lD0qTXuTXz2nH80g99Tkk9inh9g1U3uivdC40mSEvGzGrbPV7tCMLk/ X7ADQtZRtoBpR1pmioTJbcHIftziWZXga5/RmHrn1E3KyXpuwYzXLNWhrmpGrHVzjECefmX+ycyWx T8+B0Xjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vM2xd-00000006b06-26NH; Thu, 20 Nov 2025 11:36:25 +0000 Received: from mail-wm1-x32d.google.com ([2a00:1450:4864:20::32d]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vM2xa-00000006azZ-1F3I for linux-arm-kernel@lists.infradead.org; Thu, 20 Nov 2025 11:36:23 +0000 Received: by mail-wm1-x32d.google.com with SMTP id 5b1f17b1804b1-4779a4fc95aso13302465e9.1 for ; Thu, 20 Nov 2025 03:36:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763638580; x=1764243380; darn=lists.infradead.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=TPlzmXt4DNVBdqLVvxiBIWu8Rl4FZ4bDuiyypGx7MuQ=; b=LawHfCdEHTSquhn4Wh/PifORbsbA/9OCEztusBOMVeBhzplEwzXBs43JOqxiP4Ac8a 3/sBoI74xnIEeLX2fcv9euG85k1nWr2nhc/0aE2KOnnPR0p/7nEeLsFWL1I60CGuXV6H 6mYQZL5i4pTgF2/Y52f47GeMJxXkOHn3O6kigy0LHIr2FHfgyp+x1WaUm3VishA02J/g MHlXrEsQtof1vivD9damK0U0oL3u1R1wlaUfxLH/ovOA6E8QWQzzij3Tfz3Dw2cGZHUo MS6V9o1/BAIE8/5+1L0pJSAW3zCJDmkB3cYmGezvkHwJQXfyu/Jbe7FCQhpHRud7oaOB 5yzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763638580; x=1764243380; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TPlzmXt4DNVBdqLVvxiBIWu8Rl4FZ4bDuiyypGx7MuQ=; b=g9aki49nhz626ISatgLuN66SDudrcl/k0UppwEsyH00MyuR5fMr69Y4utSXnqx5q98 J9J8eTyw83ys5YFMgcs5MM2AEYof1Px146CkbvnSjSqrYXfQ3svvDZXJZVkTNtcj3EYc EcuSU++FfF48nqWossHRaWAZrdo8tz/5jXvIktrCX/mTUTER6DofJk/122ChSPwB1uSO S4n3ExyGWpJagsFf+bX0D4J7Fu9QxXG9OVnv6PO8o4y1yAqnr/llVerSSNhp4ATJnNTa +jycjj7TT1hyTt+PA1RZtVMQeTsBzKIZuxbmOXdc3HKI+oRigKAwmYp/nTispAkjrr87 ynRg== X-Forwarded-Encrypted: i=1; AJvYcCVC8gv+ccZw3rd8LdZOM8VtYpVM4CQZyNyQteEA/wh+SgYeSHglqSRQWaj/tYn5j3cdBbNolancbvKqm4+F/uW/@lists.infradead.org X-Gm-Message-State: AOJu0YwbrsTXZXNhkbyWDSa/pqjWY8pEsOVbs1y9uIA7PopbpH0DDRsm qP+M8m/JHdZYv0TBu3wBpd/1kshmuKlgGvwkYt/UaB4FMqXIhim26IT5O8Lov6GjTA== X-Gm-Gg: ASbGncsNGL5A8Dl5dVRXJsRmKUlQ6pRKglXLvbtVdKDfwzJ5OjghFZ/JpTcmnufpryd vOTql4fi2WVy33miFUN+N5LZwd4k/lW+YpFCfjCaqRTbhVYVLawD6ZFDbtwvwoYG8fh7Hd1mq1e T01C0II1HnMwGP/d9x4XJlgThFEqW7NcZnEEintCs178v6r19Oxp9BpXieIdSVQOajrN3eRsSZ6 epT5B6r+DC7KweQ7+a+TehwU+t2z46nt2FnugIfAqYcRql90uOwNGj+8Qh3rvV5rjP+qV0ssfHE fGFpEgCmGY6wyC9sEzL1w22x90QPhMrAB9tnxptXD/Mb7QE7ap5P9habo1Kbj1myp8xYtDPxepv skwfGPuzcGVECeBrRv3j1BVU30vklZSj2GIT8opuqjLcloYRrXwe9or6QdbUNNIe3o26LndaRyf t3aqhDQEYMuR7PBpCuCvgikVdSnR+RlFXrPpfrWU9rOudk+Z4PmA== X-Google-Smtp-Source: AGHT+IGcOCRDUWPkVUZ7ncQTNFf+q64GbtuEHTlJs5oKc83ztKfhHnrQKRpzLVqerrPSrM7dBJtv3A== X-Received: by 2002:a05:600c:2e4c:b0:477:9890:4528 with SMTP id 5b1f17b1804b1-477b9ea31e9mr14670485e9.2.1763638580134; Thu, 20 Nov 2025 03:36:20 -0800 (PST) Received: from google.com (120.54.38.34.bc.googleusercontent.com. [34.38.54.120]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477a9e1b657sm60238005e9.17.2025.11.20.03.36.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Nov 2025 03:36:19 -0800 (PST) Date: Thu, 20 Nov 2025 11:36:16 +0000 From: Vincent Donnefort To: Marc Zyngier , g@google.com Cc: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 20/28] KVM: arm64: Add clock support for the pKVM hyp Message-ID: References: <20251107093840.3779150-1-vdonnefort@google.com> <20251107093840.3779150-21-vdonnefort@google.com> <86cy5erprc.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86cy5erprc.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251120_033622_353510_404FAA5C X-CRM114-Status: GOOD ( 17.43 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org [...] > > +/* Using host provided data. Do not use for anything else than debugging. */ > > +u64 trace_clock(void) > > +{ > > + struct clock_data *clock = &trace_clock_data; > > + u64 bank = smp_load_acquire(&clock->cur); > > + u64 cyc, ns; > > + > > + cyc = __arch_counter_get_cntpct() - clock->data[bank].epoch_cyc; > > I can only imagine that you don't care about the broken systems that > do not have a monotonic counter, and that will happily have their > counter swing back and forth? I haven't used the _stable() variant for the affected devices... Hum this will not be trivial from the hypervisor. I'll see what I can do. > > Also, you may want to document why you are using the physical counter > instead of the virtual one. I guess that you don't want CNTVOFF_EL2 to > apply when HCR_EL2.E2H==0, but given that you never allow anything > else for pKVM, this is slightly odd. You mean I might as well use __arch_counter_get_cntvct() as CNTVOFF_EL2 will always be ignored in the pKVM case? > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible.