From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 89DF94A138E; Tue, 14 Jul 2026 15:19:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784042374; cv=none; b=EZkjp8kvsDjjS+kl19suQIAIQI8T1xtcAZakty4l0OZpC0mAR+ydz3oWvd5wpr+PnD4ZOoNavYTsAwip6woiepzY9aEPv9/5vSzri38RjpLhQF+ZJQJKOMw6reZTSgYics8ITdvnm7MmaeOaqMt9cg8FeLV2R3kP0tYg1gn6dkg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784042374; c=relaxed/simple; bh=9D9lKJ0wKpakxjOsJNH3NDApCaP89r6VUewXStMSdGI=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=VO7oltkOpBfO3UmKXqGd4vCEDyI5Sn1+4XVEERi7uxnntd+3aOcqcp6KYNksr+cKq8Oz5aRysf8WTkE1eRNO2oQPNHkg4MwtW7yntTbl3M312OSI9qDUUV0jfQmwRb8xiP3/OhEjyr/6MGmKFYmClNcYEtFtoGq6nOLn2urxyeo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mNz1L1N9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mNz1L1N9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D7BF1F000E9; Tue, 14 Jul 2026 15:19:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784042373; bh=dP5wEz+gjjaVTeNu7xmuOJx/rFtPF+YvkovZzS2m8s4=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=mNz1L1N9+nemdRXcV5RekTd9wA6qUQG43cMasGrwLuT4DFXxckZQIzcl+zo8HTyEZ XxhiJsaG8lSFEfNiCCDtFsJJBEaNYLkGubt1/sJuY+HWZMEAexGrBRkx7ZCceGDjpS FNRXl8LLPrLkCxZAmuZHas55XbhLsFFet9BHEfWTXleRD4Rfa4f8O19KjWS0kdLN71 Pe5ipnPFeBGfzH72b680CoYev53PpTHt12gzSgjOAXwAy2ZaTRkFvgbSaux4Ou97uK 7WKXe582yVanlahPOn1u5Uc09fV9E1ccml9R1W7SH9H+JJbbwdpwclwdvaWS1jJy9z Mk5NBkr8K0EVg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wjeux-00000004xgl-1XON; Tue, 14 Jul 2026 15:19:31 +0000 Date: Tue, 14 Jul 2026 16:19:30 +0100 Message-ID: <86ik6hoayl.wl-maz@kernel.org> From: Marc Zyngier To: Fuad Tabba Cc: Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Vincent Donnefort , Quentin Perret , Sebastian Ene , Hyunwoo Kim , Fuad Tabba Subject: Re: [PATCH v5 2/8] KVM: arm64: Make vcpu_{read,write}_sys_reg available to HYP code In-Reply-To: <20260714101601.4142645-3-fuad.tabba@linux.dev> References: <20260714101601.4142645-1-fuad.tabba@linux.dev> <20260714101601.4142645-3-fuad.tabba@linux.dev> 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: fuad.tabba@linux.dev, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, vdonnefort@google.com, qperret@google.com, sebastianene@google.com, imv4bel@gmail.com, tabba@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Tue, 14 Jul 2026 11:15:55 +0100, Fuad Tabba wrote: > > The vcpu_{read,write}_sys_reg() accessors are only valid on a VHE host, > so helpers built on them such as kvm_vcpu_set_be()/kvm_vcpu_is_be() > cannot be shared with hyp code. exception.c already wraps them in local > helpers that pick the host- or hyp-side accessor via has_vhe(). > > Rename the host-only implementations to __vcpu_{read,write}_sysreg_vhe() I'm a bit puzzled by this. There is nothing that makes these functions VHE-specific. Look at where they are called from: plenty of non-VHE uses. These helpers are the canonical accessors for any system register, and they don't cater for any particular mode. m. -- Without deviation from the norm, progress is not possible.