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 8D9C82749DA; Tue, 5 Aug 2025 13:21:00 +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=1754400060; cv=none; b=kvPJTq6N9vV3M+Zv0P72dV/Wx4WtrdmdnBmN8GFCmcAmyXTm6F1KR07ty4GnL11//61B6kbZk3OPJD0yyTW/yNNlXs0YNRKTvIo7fS702zGpfMytPLgKhNM/ImFWW1WWrKW3p1Y44YFYQvJD1HXzZc+t9t0/ao2Q7Obmrw2IweM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754400060; c=relaxed/simple; bh=rZtyzCT5ZXU+jXZq3GrTff5OUvmeUU0KXatEvPGAUas=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=IfCp46jWY1PAXtLin3SerDfrn3nWvSBeWZLJ9Yp10zvq6UXrEbJTuAKzaHGz8u4ncTutt3YrLWLSdT1JTtC/Kwk6PYhIU6PvV7P+Xg/3bBmskbeuDW6yomsLK5PVvSGvUa4qHrFkgwGYiVlMIbI/+BDW718+0lxYNqzgM1l1gys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uc/osURS; 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="uc/osURS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E057BC4CEF0; Tue, 5 Aug 2025 13:20:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754400059; bh=rZtyzCT5ZXU+jXZq3GrTff5OUvmeUU0KXatEvPGAUas=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uc/osURSHxYqB2uuSG8f6nMcq65HBNQruOo4GV6PXOb/0nMzee98SudcKFkmZR2WX 36ic7/F7qZSi0DbewrcWJA20RAURyvfU0nRi3zv7oEiK6wqJZio0Krtbz9D0yn0o/L /swnpVBBMUYbYOK57TWfajxKE6OJu+SZtXqZEabSWtrKNDg0Pk2DlXdYTCPPOOhCQJ 8pL2kmUNEMc6ynLXOOoAOEST9JRhZGP+04fLZIPgf0woL+CtgZ9xsovPmTICzOCzDa EhhmrEzSRuvUxIdAU7lIGtVyhtSHjZ9moh8sTSTSLP2OidDr/rK9PtmQRMOfjjTvz5 oNfghqWlEVdBg== 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 1ujHb7-004ANa-Dp; Tue, 05 Aug 2025 14:20:57 +0100 Date: Tue, 05 Aug 2025 14:20:52 +0100 Message-ID: <86fre5aoqz.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: <20250805130945.471732-59-sashal@kernel.org> References: <20250805130945.471732-1-sashal@kernel.org> <20250805130945.471732-59-sashal@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: stable@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: 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 14:09:34 +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. But I'm not even going to entertain explaining *why* backporting this patch on its own is nonsense. Reading the original series should be enlightening enough. M. -- Without deviation from the norm, progress is not possible.