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 0D30AD2502E for ; Sun, 11 Jan 2026 16:21:03 +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:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From: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=KMVdYA/3guCQa8Dbcxiyq1tWLucTmHSWlYOeBpszAjE=; b=2j++Rph9Jn2RWodcYwhSDryEU8 4CgcfjRr/bX+YKvPPk1PkaMrolj4iQ+/PRP58HVaEzDDRQfrR3dmhiyJYhj1hexBgVuTZzx0ixX5q cxSPkZYFZgBU2v2RpNRf8qwPwIlURIgnD3LhCoj/wQfqDbM3xv3uVqJr3Y8QJj5Gh1AHAaQLpSRcS ERiOl28fbYqxmMV4CCLqJRrV4Um1/jqRGzDlV6SDLmwpdErEmQssY3kI26Ahrl8GlVru5TfEIOSO4 8xfga1iL44UiO+Ey1nqbMbCNtd5ZqHg4FNu0uLI1twfzhKSW+EkYHJ2ZTToTiga1X/jHXnLdJqDCE b+TJw9/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1veyBR-00000004MZi-2njW; Sun, 11 Jan 2026 16:20:53 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1veyBQ-00000004MZB-1SvV for linux-arm-kernel@lists.infradead.org; Sun, 11 Jan 2026 16:20:52 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 124196020E; Sun, 11 Jan 2026 16:20:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3493C4CEF7; Sun, 11 Jan 2026 16:20:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768148449; bh=XxASkA9n76GnwdXuy4myQ5dyLLeDuGEtOKbjql8OspE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=WI7bynz5q61zhbhcxgLoZgd735Qm/pJNbIxIV6+NNY3x2kTRnlHiFMUbmLEayjxq1 yWVOHyHZjv8Pl4e1cwdFgcfFddfw6n0xvOnqJyleyW/500rO8uAUH+VyB5fmRpxmdV HnPBZyNHF+UqiOUxFDj/g+N1rf+k9gVtH2Hg9R2tDrTM3aCTLcWrw+bi7JNU7SSgJz 2GZH9JGLIuf/5hkcm/BZuC+ipi+gXUp+1aOc58IE2dkklwrgTokLMwqBRuJmk7S9T/ IdwcvOrAMsz0eKBHbRt2xLQfMun//6P6432sG637lpF+oChtvkkrvioKSqTfEuG+xq xypiuRQ1P3eww== From: Thomas Gleixner To: Marc Zyngier Cc: Waiman Long , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH] irqchip/gic-v3-its: Don't acquire rt_spin_lock in allocate_vpe_l1_table() In-Reply-To: <86v7h8l9ht.wl-maz@kernel.org> References: <20260107215353.75612-1-longman@redhat.com> <864iowmrx6.wl-maz@kernel.org> <87ms2nsqju.ffs@tglx> <86wm1qlq7l.wl-maz@kernel.org> <87ecnwij44.ffs@tglx> <86v7h8l9ht.wl-maz@kernel.org> Date: Sun, 11 Jan 2026 17:20:45 +0100 Message-ID: <87pl7gglya.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain 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 Sun, Jan 11 2026 at 10:38, Marc Zyngier wrote: > On Sun, 11 Jan 2026 09:39:07 +0000, > Thomas Gleixner wrote: >> >> On Fri, Jan 09 2026 at 16:13, Marc Zyngier wrote: >> > On Thu, 08 Jan 2026 22:11:33 +0000, >> > Thomas Gleixner wrote: >> >> At the point where a CPU is brought up, the topology should be known >> >> already, which means this can be allocated on the control CPU _before_ >> >> the new CPU comes up, no? >> > >> > No. Each CPU finds *itself* in the forest of redistributors, and from >> > there tries to find whether it has some shared resource with a CPU >> > that has booted before it. That's because firmware is absolutely awful >> > and can't present a consistent view of the system. >> >> Groan.... >> >> > Anyway, I expect it could be solved by moving this part of the init to >> > an ONLINE HP callback. >> >> Which needs to be before CPUHP_AP_IRQ_AFFINITY_ONLINE, but even that >> might be to late because there are callbacks in the STARTING section, >> i.e. timer, perf, which might rely on interrupts being accessible. > > Nah. This stuff is only for direct injection of vLPIs into guests, so > as long as this is done before we can schedule a vcpu on this physical > CPU, we're good. No physical interrupt is concerned with this code. That's fine then. vCPUs are considered "user-space" tasks and can't be scheduled before CPUHP_AP_ACTIVE sets the CPU active for the scheduler. Thanks, tglx