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 2D51529899A; Tue, 5 Aug 2025 18:09:43 +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=1754417384; cv=none; b=EcdwcDZpKgk7+KuRs+ltUrxUc7mrXOAwLuOogqYQ32Y5bNQdErUS42/DLP+QvAao01NKfCaTl119xZ2ULDOOVdZZn8vKYLcuZe+xUqbHD9CZNTUo11gFfT0LX20FghK6Md4z3sNB5rNSOj3iAxue6M4wkjw/xGkafUw5ULQAdrU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754417384; c=relaxed/simple; bh=CQ4211YH7bOUvS0w3ZcUchCGKPBUdDufL+8k2O3J26k=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=mJ8xEjGaXMjd751+aezD1SprIUdNCcTIpno656PAdFvMXB3HwXWkg2Ivt3Ahnl2JfYq92ALkqRUbGHQa3BVBL5YIN4H3Pja5g7dXQaIwhSruzGohMdzdxSdGvAuQVmOvwJPoD4yk/a/kzC/aWVUbGpUXFydyaGx/jgAKkUH9AsM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PfJbvBnS; 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="PfJbvBnS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A345CC4CEF8; Tue, 5 Aug 2025 18:09:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754417383; bh=CQ4211YH7bOUvS0w3ZcUchCGKPBUdDufL+8k2O3J26k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=PfJbvBnSrP5rOAkboOaaCIsUhWoV2w3ZmgbTYzuyYvGKrfuhgJIoo50Gx+cc1oL9U FlDWCTmPg6Jm42XZSHPH8e27kD/PfauwNQgWdfebDDsYpd2CqWYoJkWUUFvbpoNvgZ 4bcmb0IBl9juSVM5ROKJCHJVlm9FPLL9ljpRsDRnYzbTphx+WHT5RxwzCgE3YIo+j8 fZOJeXcP605ltX3o2lYkwqWdonu83Ot+uygxLMjwke3FhxZUoYCCEXL4vo486VFreF pHesL1ye5xlTSUcqynUsqv9XCxk4xdiZVc66sieGUmmfkurfr7X4FMLywR4qAQwpMo X/Z+Z1cacIl0w== 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 4.95) (envelope-from ) id 1ujM6X-004F3q-5r; Tue, 05 Aug 2025 19:09:41 +0100 Date: Tue, 05 Aug 2025 19:09:40 +0100 Message-ID: <877bzhtzbv.wl-maz@kernel.org> From: Marc Zyngier To: Sasha Levin Cc: patches@lists.linux.dev, stable@vger.kernel.org, Lorenzo Pieralisi , Bjorn Helgaas , toan@os.amperecomputing.com, kwilczynski@kernel.org, mani@kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH AUTOSEL 6.16-6.6] PCI: xgene-msi: Resend an MSI racing with itself on a different CPU In-Reply-To: References: <20250805130945.471732-1-sashal@kernel.org> <20250805130945.471732-59-sashal@kernel.org> <86fre5aoqz.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/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: patches@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: sashal@kernel.org, patches@lists.linux.dev, stable@vger.kernel.org, lpieralisi@kernel.org, bhelgaas@google.com, toan@os.amperecomputing.com, kwilczynski@kernel.org, mani@kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Tue, 05 Aug 2025 14:59:27 +0100, Sasha Levin wrote: > > On Tue, Aug 05, 2025 at 02:20:52PM +0100, Marc Zyngier wrote: > > On Tue, 05 Aug 2025 14:09:34 +0100, > > Sasha Levin wrote: > >> > >> From: Marc Zyngier > >> > >> [ Upstream commit 3cc8f625e4c6a0e9f936da6b94166e62e387fe1d ] > >> > >> Since changing the affinity of an MSI really is about changing > >> the target address and that it isn't possible to mask an individual > >> MSI, it is completely possible for an interrupt to race with itself, > >> usually resulting in a lost interrupt. > >> > >> Paper over the design blunder by informing the core code of this > >> sad state of affairs. > >> > >> Signed-off-by: Marc Zyngier > >> Signed-off-by: Lorenzo Pieralisi > >> Signed-off-by: Bjorn Helgaas > >> Link: https://lore.kernel.org/r/20250708173404.1278635-11-maz@kernel.org > >> Signed-off-by: Sasha Levin > >> --- > >> > >> LLM Generated explanations, may be completely bogus: > > > > s/may be//. It is an amusing read though, specially when quoting > > totally unrelated patches, so thumbs up for the comical value. > > Yeah, it's still very much at the "junior engineer" level It's not, and that's the main issue. A junior engineer would get into the rabbit hole of backporting too much, as they would be unable to separate the essential logic from the surrounding fluff. There would be a lot of noise, but it would be OK. Your "thing" is very much at the "Senior Marketroid" level, in the sense that it manages to drag some semi-relevant information from various sources, and condenses it into an advertisement for snake oil. I think I know who which of the two I want to work with. M. -- Jazz isn't dead. It just smells funny.