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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) 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241220_031705_223700_135DD3D3 X-CRM114-Status: GOOD ( 17.09 ) 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 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.