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 A86E7315D45 for ; Sat, 6 Sep 2025 20:48:29 +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=1757191709; cv=none; b=BVKjvsV8jtaVBf1a2qkbJUHaRs1N9E5Z/oey1cI07wGKNozS/3vUkcr9+zc82J7qB6K4XrU3koeC/rm1gUTQR0RZBMw2WVyz0HWxcGfpvr6qqLU2azZvdUMb714cEYhg/S4U3AvsmS5CbqIrZambx+JZSdFg2FNWXqDlH5Og8GQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757191709; c=relaxed/simple; bh=m/Kr6UFeaFWjGi4YnpwtrrzZ5wXDjB8jXsBf/7v7Yu4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Gsxjj4awvpLbOmvD/MI02jZsillZJ0yIIq/gQjO4mUGBChQ56jDav5BjAyp1NnIfYUJZjMnZV9DVSy3xv2iO4YcY9XyRGoaIVNlY/4ISoeKfAI4NO75QJlNOcU3woArZdzQHGRIixva/quumv4r4KdsA+/88iSY3dhfX6ExFwoo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZoZEv1FK; 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="ZoZEv1FK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E59EC4CEE7; Sat, 6 Sep 2025 20:48:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757191709; bh=m/Kr6UFeaFWjGi4YnpwtrrzZ5wXDjB8jXsBf/7v7Yu4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZoZEv1FKHysbnlwJAihlnApDPtQv5v+UI2mGiUHkDf6jCWViMMpKV9fhFOj81WjT0 CPXo39UNIYF77gmYQWsnxImrTR5Pzky4LIGaOcw1W5ysw0s8+o5lhOdoXyuXq0hrpI xSlmS/i2MvWG6dPL97RAKQP2zEooT1NsgcwrMOl45ilPu9leeIcUxzxGu345GWzvID +9CqRwrLfUUVdCll3VUUSE48dD72P55iwblV4hZrO5X8ZMvyIiOsr4IaHh3RK8gmdL /tBx2oT0yw22/U7H7MUNmJnj6XGqQRUe6ZAW6qPy30JT1pGNDpmKDwKLiEi9rWH9CU vO1rtAHtSiDfw== From: Sasha Levin To: stable@vger.kernel.org Cc: Jonathan Currier , Thomas Gleixner , Sasha Levin Subject: [PATCH 6.1.y] PCI/MSI: Add an option to write MSIX ENTRY_DATA before any reads Date: Sat, 6 Sep 2025 16:48:26 -0400 Message-ID: <20250906204826.282978-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025042120-skimming-facing-a7af@gregkh> References: <2025042120-skimming-facing-a7af@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jonathan Currier [ Upstream commit cf761e3dacc6ad5f65a4886d00da1f9681e6805a ] Commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") introduced a readl() from ENTRY_VECTOR_CTRL before the writel() to ENTRY_DATA. This is correct, however some hardware, like the Sun Neptune chips, the NIU module, will cause an error and/or fatal trap if any MSIX table entry is read before the corresponding ENTRY_DATA field is written to. Add an optional early writel() in msix_prepare_msi_desc(). Fixes: 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") Signed-off-by: Jonathan Currier Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20241117234843.19236-2-dullfire@yahoo.com [ Applied workaround to msix_setup_msi_descs() instead of msix_prepare_msi_desc() ] Signed-off-by: Sasha Levin --- drivers/pci/msi/msi.c | 3 +++ include/linux/pci.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index c5cc3e453fd0c..7110aed956c75 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -534,6 +534,9 @@ static int msix_setup_msi_descs(struct pci_dev *dev, void __iomem *base, if (desc.pci.msi_attrib.can_mask) { addr = pci_msix_desc_addr(&desc); + /* Workaround for SUN NIU insanity, which requires write before read */ + if (dev->dev_flags & PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST) + writel(0, addr + PCI_MSIX_ENTRY_DATA); desc.pci.msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL); } diff --git a/include/linux/pci.h b/include/linux/pci.h index df36df4695ed5..59dfa59d6d597 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -244,6 +244,8 @@ enum pci_dev_flags { PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11), /* Device does honor MSI masking despite saying otherwise */ PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12), + /* Device requires write to PCI_MSIX_ENTRY_DATA before any MSIX reads */ + PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST = (__force pci_dev_flags_t) (1 << 13), }; enum pci_irq_reroute_variant { -- 2.51.0