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 46FEA2AE96 for ; Fri, 20 Dec 2024 11:17:03 +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=1734693424; cv=none; b=hAjg4U1AVGNiz0WQMF5tt+whaTOayzP3arLRIJQdO09gRADPrxrHGdLfezqCe0kChk7m0th427yYo2eFVIQGbTw/bio4x5sEjsnBIJ0l1BmPYLIc2vnqXVMvsXAphfkLf3eooAShf+0n1s+vCyr7jGFHP37pvJjPN8tzY1Vo05I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734693424; c=relaxed/simple; bh=GNSiQOlVVh4t42W4baERM9m5qIWhn14nqFaGFOc0eJg=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=JGtbTsZL03iScbRzR/AFxt3Qvy58v62wQMLr9Puc8UcunG7IB5PWGrcDSuS56zUpX3LtcDMbCJH1JudolmR6W/7DTx3HPk3ro0frv9yq9RkC4I2G+j1cf2buoiCdlfoY5g9sAo+MrTbFstlara+pWZIiQAHmGo/WmWK9sRvZrqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uj0Dt//d; 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="uj0Dt//d" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC4C7C4CED4; Fri, 20 Dec 2024 11:17:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734693423; bh=GNSiQOlVVh4t42W4baERM9m5qIWhn14nqFaGFOc0eJg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uj0Dt//dGVeJsURaAhcxXN0MwZJrJA7xRV8LD4ZQFcdqOVMWMajmjKTajikcHncjT 9hkdbHI+9zvkng7g6weMMjbd0Sq69BkYNWFbwu5jLuo/Khr8YpM+itFkhIE7WioIBy VK4srGnqwLMy+VLqxGxUUg8ofN5w0GLjtaty3C6GK3UdH+dMPgwHIWqv5FUwrSLDqA 6J5t96vvZa9eZumvZG7AYm0wXRuTO4Cqc/WeHNKKNuKQhBHXGKw9y+w4BqxfcKDsPF 0mPxkiDD+CEAQN6vseekr2KTpZS0AYV6J0xieZv6gImjEQqpVgTlJ39uLxfLqJnsno MDVJCEupljFig== 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 4.95) (envelope-from ) id 1tOb09-005cZe-Ey; Fri, 20 Dec 2024 11:17:01 +0000 Date: Fri, 20 Dec 2024 11:17:00 +0000 Message-ID: <86v7veppsj.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: Shameer Kolothum , kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, cohuck@redhat.com, eric.auger@redhat.com, sebott@redhat.com, yuzenghui@huawei.com, wangzhou1@hisilicon.com, jiangkunkun@huawei.com, jonathan.cameron@huawei.com, anthony.jebson@huawei.com, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com Subject: Re: [PATCH v4 3/3] arm64: paravirt: Enable errata based on implementation CPUs In-Reply-To: References: <20241218105345.73472-1-shameerali.kolothum.thodi@huawei.com> <20241218105345.73472-4-shameerali.kolothum.thodi@huawei.com> <86bjx8q995.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/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev 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: oliver.upton@linux.dev, shameerali.kolothum.thodi@huawei.com, kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, cohuck@redhat.com, eric.auger@redhat.com, sebott@redhat.com, yuzenghui@huawei.com, wangzhou1@hisilicon.com, jiangkunkun@huawei.com, jonathan.cameron@huawei.com, anthony.jebson@huawei.com, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Thu, 19 Dec 2024 17:40:55 +0000, Oliver Upton wrote: > > > Independent of this, I wonder what we should output in sysfs > > (/sys/devices/system/cpu/cpu*/regs/identification/*). > > It's a bit crap, but maybe implementation index 0 gets reported through > the 'main' midr/revidr files, otherwise have a directory per > implementation index of midr/revidr. Having slept on that one, I'm starting to think that we should keep the status-quo of reporting what the kernel snapshot at boot time. There is no good reason to force the VMM to report the potential implementations in any specific order. The "alternative-implementations" is interesting, but we don't keep it per-CPU, so I don't think it fits the current scheme. But maybe something in /sys/devices/system/cpu, outside of the cpu* hierarchy? Either way, this isn't something we should worry too much right now. Thanks, M. -- Without deviation from the norm, progress is not possible.