From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF085F9EC; Fri, 18 Apr 2025 15:34:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744990460; cv=none; b=mizMM60wi4+o1wqcbxYR6hcyRcsiSzVEue2BKkZptGHmUuhzr6hrXihmA6PwsoNi6ZbNuvjFmiaIc3Rv1t0eHm2sG288FRlxyc3KgwUoob1hVpajtVmQ/K6s5KzFi1I0KfnZ+vw24XDzhz8D39fAtBcTuLVoicQi9DM4LX0N2qI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744990460; c=relaxed/simple; bh=IqfrOwyWG1N8zLTNAckQ4CesOQiehJPTCr+QzFBVjGs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=FC0S3XmfKdJ7HTeCiOUzX/As0pyyNr4+wQ8qpKts5sfHamfO355PC/RuZR2lZbEQYK70Ox75uqU0Skx0LmBzK9S+aHJzAzxx3xEVu0425OU0zWumUySnDLJTfjHLUPwKC7icffBW0st+ZAZmMluvwfvbugfY2bGz9s5YeySv12c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=et66A57S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="et66A57S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 144EBC4CEE2; Fri, 18 Apr 2025 15:34:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744990460; bh=IqfrOwyWG1N8zLTNAckQ4CesOQiehJPTCr+QzFBVjGs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=et66A57SS/IazT+ZIFZOnE/SV7kXE0YSB2A+AgbN9eawLOkguleCnHto3In11sj3+ Hb1KRy+Ae4atyNjU6LAQxacjh2MUf1Bboc57G7MhdWEoUVSUdzAhw0fFu8+dgl2b8N 7+BHnalydI97FgNGAhkVKjmB0O/INXiH9gh4c1s+63FZVasjjSpu8w5Hd0upTj66s3 VrWUql5C1aMU0cjSxjD1XGXkwEwvc3oTLEjAYj7GcL6oIIz6HNR5U1PdPzbFPooCvL rtps9pNwW0ENOXP1ibttsWT8Ki1qBzrcsbqmL+zdIjb6t8ySHyeDGbCcc+ufCehoeO w4fjuKis6mpew== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1u5njN-006kqc-IK; Fri, 18 Apr 2025 16:34:17 +0100 Date: Fri, 18 Apr 2025 16:34:24 +0100 Message-ID: <87r01pxz3z.wl-maz@kernel.org> From: Marc Zyngier To: Yury Norov Cc: Luo Jie , Rasmus Villemoes , Julia Lawall , Nicolas Palix , Catalin Marinas , Will Deacon , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , linux-kernel@vger.kernel.org, cocci@inria.fr, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, andrew@lunn.ch, quic_kkumarcs@quicinc.com, quic_linchen@quicinc.com, quic_leiwei@quicinc.com, quic_suruchia@quicinc.com, quic_pavir@quicinc.com Subject: Re: [PATCH v3 4/6] arm64: nvhe: Convert the opencoded field modify In-Reply-To: References: <20250417-field_modify-v3-0-6f7992aafcb7@quicinc.com> <20250417-field_modify-v3-4-6f7992aafcb7@quicinc.com> <86r01rjald.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: yury.norov@gmail.com, quic_luoj@quicinc.com, linux@rasmusvillemoes.dk, Julia.Lawall@inria.fr, nicolas.palix@imag.fr, catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-kernel@vger.kernel.org, cocci@inria.fr, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, andrew@lunn.ch, quic_kkumarcs@quicinc.com, quic_linchen@quicinc.com, quic_leiwei@quicinc.com, quic_suruchia@quicinc.com, quic_pavir@quicinc.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Fri, 18 Apr 2025 16:14:48 +0100, Yury Norov wrote: > > On Thu, Apr 17, 2025 at 12:23:10PM +0100, Marc Zyngier wrote: > > On Thu, 17 Apr 2025 11:47:11 +0100, > > Luo Jie wrote: > > > > > > Replaced below code with the wrapper FIELD_MODIFY(MASK, ®, val) > > > - reg &= ~MASK; > > > - reg |= FIELD_PREP(MASK, val); > > > The semantic patch that makes this change is available > > > in scripts/coccinelle/misc/field_modify.cocci. > > > > > > More information about semantic patching is available at > > > https://coccinelle.gitlabpages.inria.fr/website > > > > > > Signed-off-by: Luo Jie > > > --- > > > arch/arm64/kvm/hyp/include/nvhe/memory.h | 3 +-- > > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > > > diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h > > > index 34233d586060..b2af748964d0 100644 > > > --- a/arch/arm64/kvm/hyp/include/nvhe/memory.h > > > +++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h > > > @@ -30,8 +30,7 @@ enum pkvm_page_state { > > > static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot, > > > enum pkvm_page_state state) > > > { > > > - prot &= ~PKVM_PAGE_STATE_PROT_MASK; > > > - prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state); > > > + FIELD_MODIFY(PKVM_PAGE_STATE_PROT_MASK, &prot, state); > > > return prot; > > > } > > > > Following up on my suggestion to *not* add anything new, this patch > > could be written as: > > > > diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h > > index 34233d5860607..08cb6ba0e0716 100644 > > --- a/arch/arm64/kvm/hyp/include/nvhe/memory.h > > +++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h > > @@ -30,9 +30,8 @@ enum pkvm_page_state { > > static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot, > > enum pkvm_page_state state) > > { > > - prot &= ~PKVM_PAGE_STATE_PROT_MASK; > > - prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state); > > - return prot; > > + u64 p = prot; > > + return u64_replace_bits(p, state, PKVM_PAGE_STATE_PROT_MASK); > > } > > This is a great example where u64_replace_bit() should NOT be used. Well, I'll like well it enough. M. -- Jazz isn't dead. It just smells funny.