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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 7666FC433E0 for ; Mon, 29 Jun 2020 11:05:22 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 02721239EF for ; Mon, 29 Jun 2020 11:05:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02721239EF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 77EDE4B3C6; Mon, 29 Jun 2020 07:05:21 -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 k52kl96fQiGl; Mon, 29 Jun 2020 07:05:20 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 4EDB74B3E9; Mon, 29 Jun 2020 07:05:20 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 555A34B35B for ; Mon, 29 Jun 2020 07:05:19 -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 nUpKmUV-FRzG for ; Mon, 29 Jun 2020 07:05:18 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 3BAC24B332 for ; Mon, 29 Jun 2020 07:05:18 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D37F313D5; Mon, 29 Jun 2020 04:05:17 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.20.135]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7E5C03F73C; Mon, 29 Jun 2020 04:05:16 -0700 (PDT) Date: Mon, 29 Jun 2020 12:05:13 +0100 From: Mark Rutland To: Gavin Shan Subject: Re: [PATCH 1/2] kvm/arm64: Rename HSR to ESR Message-ID: <20200629110513.GC59769@C02TD0UTHF1T.local> References: <20200629091841.88198-1-gshan@redhat.com> <20200629091841.88198-2-gshan@redhat.com> <20200629103208.GA59769@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200629103208.GA59769@C02TD0UTHF1T.local> Cc: catalin.marinas@arm.com, will@kernel.org, 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 Mon, Jun 29, 2020 at 11:32:08AM +0100, Mark Rutland wrote: > On Mon, Jun 29, 2020 at 07:18:40PM +1000, Gavin Shan wrote: > > kvm/arm32 isn't supported since commit 541ad0150ca4 ("arm: Remove > > 32bit KVM host support"). So HSR isn't meaningful since then. This > > renames HSR to ESR accordingly. This shouldn't cause any functional > > changes: > > > > * Rename kvm_vcpu_get_hsr() to kvm_vcpu_get_esr() to make the > > function names self-explanatory. > > * Rename variables from @hsr to @esr to make them self-explanatory. > > > > Signed-off-by: Gavin Shan > > At a high-level, I agree that we should move to the `esr` naming to > match the architecture and minimize surprise. However, I think there are > some ABI changes here, which *are* funcitonal changes, and those need to > be avoided. > > [...] > > > diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h > > index ba85bb23f060..d54345573a88 100644 > > --- a/arch/arm64/include/uapi/asm/kvm.h > > +++ b/arch/arm64/include/uapi/asm/kvm.h > > @@ -140,7 +140,7 @@ struct kvm_guest_debug_arch { > > }; > > > > struct kvm_debug_exit_arch { > > - __u32 hsr; > > + __u32 esr; > > __u64 far; /* used for watchpoints */ > > }; > > This is userspace ABI, and changing this *will* break userspace. This > *is* a functional change. To be slightly clearer: while the structure isn't changed, any userspace software consuming this header will fail to build after this change, beacause there will no longer be a field called `hsr`. Existing binaries will almost certianly not care, but regardless this is a regression (when building userspce) that I don't think we can permit. Thanks, Mark. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm