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 E13C53A8741; Wed, 8 Jul 2026 10:24:50 +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=1783506292; cv=none; b=UXu9AEa08Qlk3VkVtgvrZlsJB+WYNuBZYq5NXNYt0zFtxiWAG8dz8NI2b1BT+uaMjN6q3XdFE/poZdsXN44b0FmrhYtT8evhzHyoQcVni3WpGf04IIhHTguWTx6/Y1FoP61GG7ZhHBpUwAPHw0X6uVAdMQtubAt683W4WHwTfq8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783506292; c=relaxed/simple; bh=u7FkhcYjK3fyL7Y4GP1au1HKa4jSSg17Kxp9saEa0Ec=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=k5E3VsLbiS22zcXqme7CrPQ0x/yPNgm8vIg7M8RkorpbMQzbwqVPUSTJO3mBpWPt5bfCqv6TN5rtijDjjicw4Q+ZXDN84119oJN9WMyWfQvSRRhJNfgBc9YCp/xN07Q4HQBXgz121EfxbsaIzG973xXg1U4b+nZpWquM6Tf2mvA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G0JAAg3c; 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="G0JAAg3c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 865231F000E9; Wed, 8 Jul 2026 10:24:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783506290; bh=zSfm6Hy5p1eTVe6xsQSBGh/nMEACx2PFvy9wwc0WZWs=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=G0JAAg3caBWmNn7VbMRqrtSqx0vsnaBohbRYhqIF01Ze+7Tu3O4U4Yh6SvRdLLr7c xwlt8dvvlhbjGPXb/Iy1w6lA1pGirhTQ1r4BVCN2DCivqL7qyqxpMeDyX4es/SxolR IrRBdi6v8787TOSi5835bwAOTupvDffYUUOet0N69h1OBiK8w+lG2sPyIlNQg4PQyV As/0jZ/sSEYvkHfw9cu5saTG0m8v2aIjqJFFoEJFkY2r29CCSYfqIfvqioymRklZFy I+BBbccSOEOaX6WR0tlY1V8weC4cxVXZW4YIWo4em2eZytAXrbgih+lJckXHioJrfs 4SZPOFW249CWA== 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 4.98.2) (envelope-from ) id 1whPSS-00000002m0e-0dnB; Wed, 08 Jul 2026 10:24:48 +0000 Date: Wed, 08 Jul 2026 11:26:37 +0100 Message-ID: <875x2p7p5u.wl-maz@kernel.org> From: Marc Zyngier To: Bjoern Doebel Cc: , Thomas Gleixner , , , David Woodhouse , "Ali\ Saidi" , David Arinzon , "Zeev\ Zilberman" Subject: Re: [PATCH] irqchip/gic-v3-its: Reconfigure ITS from software state on resume In-Reply-To: References: <20260507183102.1897629-1-doebel@amazon.de> 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: doebel@amazon.de, stable@vger.kernel.org, tglx@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, dwmw@amazon.co.uk, alisaidi@amazon.com, darinzon@amazon.com, zeev@amazon.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, 02 Jul 2026 12:57:15 +0100, Bjoern Doebel wrote: > > Hi all, > > gentle ping on this one. > > Since the original posting I've re-validated the fix against current > mainline: > > - It still applies cleanly to v7.2-rc1 (and to v7.1.0). > > - I reproduced the original failure on *stock* v7.2-rc1. On EC2 > Graviton instances, hibernation resume fails 100% of the time: the > ITS comes back reset, MAPD/MAPTI are never replayed, and the ENA > NIC silently loses its LPIs: > > ena 0000:00:05.0: ... didn't receive a MSI-X interrupt (cmd 3) > ena 0000:00:05.0: Failed to create IO CQ. error: -62 > But how did the resumed kernel get there the first place? Surely you had interrupts to load it, right? > The instance then has no networking after resume. > > - With this patch applied, the same kernel survives hibernate/resume > cleanly: 9/9 cycles with zero failures, across all three Graviton > generations (Graviton 2/3/4, i.e. Neoverse N1/V1/V2), networking > fully restored on every resume. > > As described in the previous message, this is the fallout from 713335b6ee29 > ("irqchip/gic-v3-its: Implement .msi_teardown() callback"): device > teardown no longer happens across a suspend/resume that keeps the MSI > domain, so the ITS is never reprogrammed and drops interrupts after the > hardware has been reset. > > Could you take a look when you get a chance? What I don't immediately see is how this particular patch influences anything, given that at this point it isn't doing anything. Beside that, how does hibernation actually influences LPIs being released? Can you at least describe the sequence of events? The other thing that worries me is that in general, (bare metal) GICv3 is unable to deal with hibernation, given that you can't reprogram the property and pending table addresses. Yes, it *may* work if you are lucky enough that the boot kernel and the resumed one use the same memory regions, but this only show that you like playing Russian roulette. Thanks, M. -- Jazz isn't dead. It just smells funny.