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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 F3C1DC433E0 for ; Tue, 30 Mar 2021 16:49:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C91C0619CC for ; Tue, 30 Mar 2021 16:49:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231752AbhC3Qs6 (ORCPT ); Tue, 30 Mar 2021 12:48:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:58250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232778AbhC3Qrz (ORCPT ); Tue, 30 Mar 2021 12:47:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 83214619CC; Tue, 30 Mar 2021 16:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617122875; bh=KHdICeV1rM9Mb1vyk4HNCW+NjRO4QlezycJ0HLjScfo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SPVAcoxLcZywaF/4CUfIl92hsw2AIuUB+TptV2Vf6Lz8JR4+42XDb2TSB6g0sPyB8 NNltxUHwHJwX5kJddk13kPhpTeI5wth35YAcFCIVXupqIQreho71ppZPLb9fA4e1uy mYHnuq9H4bikcys3Nln/+Df8ph/V4o2xI19DrGq8= Date: Tue, 30 Mar 2021 18:47:52 +0200 From: Greg KH To: Mathieu Poirier Cc: Suzuki K Poulose , Marc Zyngier , Catalin Marinas , linux-arm-kernel , Linux Kernel Mailing List , Coresight ML , Mike Leach , Leo Yan , Anshuman Khandual , Will Deacon , Mark Rutland Subject: Re: [PATCH v5 07/19] arm64: kvm: Enable access to TRBE support for host Message-ID: References: <20210323120647.454211-1-suzuki.poulose@arm.com> <20210323120647.454211-8-suzuki.poulose@arm.com> <20210326165550.GC2009902@xps15> <20210330152314.GA2329603@xps15> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 30, 2021 at 10:33:51AM -0600, Mathieu Poirier wrote: > On Tue, 30 Mar 2021 at 09:35, Greg KH wrote: > > > > On Tue, Mar 30, 2021 at 09:23:14AM -0600, Mathieu Poirier wrote: > > > On Tue, Mar 30, 2021 at 11:38:18AM +0100, Suzuki K Poulose wrote: > > > > On 26/03/2021 16:55, Mathieu Poirier wrote: > > > > > On Tue, Mar 23, 2021 at 12:06:35PM +0000, Suzuki K Poulose wrote: > > > > > > For a nvhe host, the EL2 must allow the EL1&0 translation > > > > > > regime for TraceBuffer (MDCR_EL2.E2TB == 0b11). This must > > > > > > be saved/restored over a trip to the guest. Also, before > > > > > > entering the guest, we must flush any trace data if the > > > > > > TRBE was enabled. And we must prohibit the generation > > > > > > of trace while we are in EL1 by clearing the TRFCR_EL1. > > > > > > > > > > > > For vhe, the EL2 must prevent the EL1 access to the Trace > > > > > > Buffer. > > > > > > > > > > > > Cc: Will Deacon > > > > > > Cc: Catalin Marinas > > > > > > Cc: Marc Zyngier > > > > > > Cc: Mark Rutland > > > > > > Cc: Anshuman Khandual > > > > > > Acked-by: Mathieu Poirier > > > > > > Signed-off-by: Suzuki K Poulose > > > > > > --- > > > > > > arch/arm64/include/asm/el2_setup.h | 13 +++++++++ > > > > > > arch/arm64/include/asm/kvm_arm.h | 2 ++ > > > > > > arch/arm64/include/asm/kvm_host.h | 2 ++ > > > > > > arch/arm64/kernel/hyp-stub.S | 3 ++- > > > > > > arch/arm64/kvm/debug.c | 6 ++--- > > > > > > arch/arm64/kvm/hyp/nvhe/debug-sr.c | 42 ++++++++++++++++++++++++++++++ > > > > > > arch/arm64/kvm/hyp/nvhe/switch.c | 1 + > > > > > > 7 files changed, 65 insertions(+), 4 deletions(-) > > > > > > > > > > > > > > > > Marc - do you want me to pick up this one? > > > > > > > > I think the kvmarm tree is the best route for this patch, given the amount > > > > of changes the tree is going through, in the areas this patch > > > > touches. Or else there would be conflicts with merging. And this patch > > > > depends on the patches from this series that were queued. > > > > > > > > Here is the depency tree : > > > > > > > > a) kvm-arm fixes for debug (Patch 1, 2) & SPE save-restore fix (queued in > > > > v5.12-rc3) > > > > > > > > b) TRBE defintions and Trace synchronization barrier (Patches 5 & 6) > > > > > > > > c) kvm-arm TRBE host support (Patch 7) > > > > > > > > d) TRBE driver support (and the ETE changes) > > > > > > > > > > > > (c) code merge depends on -> (a) + (b) > > > > (d) build (no conflicts) depends on -> (b) > > > > > > > > > > > > Now (d) has an indirect dependency on (c) for operational correctness at > > > > runtime. > > > > So, if : > > > > > > > > kvmarm tree picks up : b + c > > > > coresight tree picksup : b + d > > > > > > > > and if we could ensure the merge order of the trees are in > > > > kvmarm > > > > greg-kh (device-misc tree) (coresight goes via this tree) > > > > > > > > > > Greg's char-misc tree is based on the rc releases rather than next. As such it > > > is a while before other branches like kvmarm get merged, causing all sort of > > > compilation breakage. > > > > My tree can not be based on -next, and neither can any other > > maintainer's tree, as next is composed of maintainer trees :) > > > > Exactly > > > > > we should be fine. > > > > > > > > Additionally, we could rip out the Kconfig changes from the TRBE patch > > > > and add it only at the rc1, once we verify both the trees are in to make > > > > sure the runtime operation dependency is not triggered. > > > > > > > > > > We could also do that but Greg might frown at the tactic, and rightly so. The > > > usual way to work with complex merge dependencies is to proceed in steps, which > > > would mean that all KVM related patches go in the v5.13 merge window. When that > > > is done we add the ETE/TRBE for the v5.14 merge window. I agree that we waste > > > an entire cycle but it guarantees to avoid breaking builds and follows the > > > conventional way to do things. > > > > Or someone creates a single branch with a signed tag and it gets pulled > > into multiple maintainer's trees and never rebased. We've done that > > lots of time, nothing new there. Or everything goes through one tree, > > or you wait a release cycle. > > > > You have 3 choices, pick one :) > > I'm perfectly happy with getting this entire set merged via Marc's > kvmarm tree, as long as you are fine with it. No objection from me at all for this to go that way. thanks, greg k-h