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 18917C3DA5D for ; Thu, 25 Jul 2024 15:14:17 +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=PAy1Q+WPwOFnxEWdWga4eM7YCpgqHj9ByXIurjv42kg=; b=ajaQpachigIpT6xfeDR1zyYPy/ obs2aD9MW9iNgdxhk8gT7iAuCn2D+oNCKXOf5SINI+APGCVwIvmPaFLALFpjEA/YYX6AZRNNWP9c1 KP8+lNDvPYohKBc7cHJ5DWJnjkamJdHZS5CpYAchq4JKPeufetLShUQFUewHkyex2ZEN07LYjHFJS u7CPts1vcr5FenPTDSxqe7MeIMCwphcKgBHs7NCROT2gbN818Mn6DGv5adUxBsZ6UYgtRdvime8gs MAfFDl4uAZJEqPbpB0BWOXpK53lTvIH9ktSlyzeJmWQU600jj9FRRN9tabinbv/286t6CaDV+136W u98leQAw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sX0AI-00000001Ng3-1qsW; Thu, 25 Jul 2024 15:13:58 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sX09t-00000001Ncl-0UpM for linux-arm-kernel@lists.infradead.org; Thu, 25 Jul 2024 15:13:34 +0000 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 7FFA01007; Thu, 25 Jul 2024 08:13:55 -0700 (PDT) Received: from raptor (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 62D113F73F; Thu, 25 Jul 2024 08:13:28 -0700 (PDT) Date: Thu, 25 Jul 2024 16:13:25 +0100 From: Alexandru Elisei To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Joey Gouly Subject: Re: [PATCH 10/12] KVM: arm64: nv: Add SW walker for AT S1 emulation Message-ID: References: <20240625133508.259829-1-maz@kernel.org> <20240708165800.1220065-1-maz@kernel.org> <864j8d35p3.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <864j8d35p3.wl-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240725_081333_399270_37B90A05 X-CRM114-Status: GOOD ( 21.58 ) 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 Hi, On Thu, Jul 25, 2024 at 03:30:00PM +0100, Marc Zyngier wrote: > On Thu, 25 Jul 2024 15:16:12 +0100, > Alexandru Elisei wrote: > > > > Hi Marc, > > > > On Mon, Jul 08, 2024 at 05:57:58PM +0100, Marc Zyngier wrote: > > > + if (perm_fail) { > > > + struct s1_walk_result tmp; > > > > I was wondering if you would consider initializing 'tmp' to the empty struct > > here. That makes it consistent with the initialization of 'wr' in the !perm_fail > > case and I think it will make the code more robust wrt to changes to > > compute_par_s1() and what fields it accesses. > > I think there is a slightly better way, with something like this: > > diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c > index b02d8dbffd209..36fa2801ab4ef 100644 > --- a/arch/arm64/kvm/at.c > +++ b/arch/arm64/kvm/at.c > @@ -803,12 +803,12 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) > } > > if (perm_fail) { > - struct s1_walk_result tmp; > - > - tmp.failed = true; > - tmp.fst = ESR_ELx_FSC_PERM | wr.level; > - tmp.s2 = false; > - tmp.ptw = false; > + struct s1_walk_result tmp = (struct s1_walk_result){ > + .failed = true, > + .fst = ESR_ELx_FSC_PERM | wr.level, > + .s2 = false, > + .ptw = false, > + }; > > wr = tmp; > } > > Thoughts? How about (diff against your kvm-arm64/nv-at-pan-WIP branch, in case something looks off): diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c index b02d8dbffd20..74ebe3223a13 100644 --- a/arch/arm64/kvm/at.c +++ b/arch/arm64/kvm/at.c @@ -802,16 +802,8 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) BUG(); } - if (perm_fail) { - struct s1_walk_result tmp; - - tmp.failed = true; - tmp.fst = ESR_ELx_FSC_PERM | wr.level; - tmp.s2 = false; - tmp.ptw = false; - - wr = tmp; - } + if (perm_fail) + fail_s1_walk(&wr, ESR_ELx_FSC_PERM | wr.level, false, false); compute_par: return compute_par_s1(vcpu, &wr); Thanks, Alex