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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71A24C5ACB3 for ; Wed, 15 Nov 2023 21:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235050AbjKOVwp (ORCPT ); Wed, 15 Nov 2023 16:52:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344434AbjKOUz7 (ORCPT ); Wed, 15 Nov 2023 15:55:59 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A43BCD48 for ; Wed, 15 Nov 2023 12:55:54 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E71BC4E777; Wed, 15 Nov 2023 20:55:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700081754; bh=/d8Vp9XUVcsELl21/fgVBw0WuDo8LAmO+Y3GOJ2cOaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=szZEhAlizHnsDBCz3k3JH54kOzjrTNSZN4QJP90DxxgYOQP4+Bq6xgFR1m9on7Sy4 jdb6y8B5CxxzirF/QeD2BSWS63k0CdVXRt6knSztnA23ZDZf4SdWF/+gMhfJOzagzz lR/n0V/7L4xTEbIF/9dmEX1Rgo11upiq/WAlCsiI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= , Juergen Gross , Sasha Levin Subject: [PATCH 5.10 079/191] xen-pciback: Consider INTx disabled when MSI/MSI-X is enabled Date: Wed, 15 Nov 2023 15:45:54 -0500 Message-ID: <20231115204649.339140978@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115204644.490636297@linuxfoundation.org> References: <20231115204644.490636297@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Marczykowski-Górecki [ Upstream commit 2c269f42d0f382743ab230308b836ffe5ae9b2ae ] Linux enables MSI-X before disabling INTx, but keeps MSI-X masked until the table is filled. Then it disables INTx just before clearing MASKALL bit. Currently this approach is rejected by xen-pciback. According to the PCIe spec, device cannot use INTx when MSI/MSI-X is enabled (in other words: enabling MSI/MSI-X implicitly disables INTx). Change the logic to consider INTx disabled if MSI/MSI-X is enabled. This applies to three places: - checking currently enabled interrupts type, - transition to MSI/MSI-X - where INTx would be implicitly disabled, - clearing INTx disable bit - which can be allowed even if MSI/MSI-X is enabled, as device should consider INTx disabled anyway in that case Fixes: 5e29500eba2a ("xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too") Signed-off-by: Marek Marczykowski-Górecki Acked-by: Juergen Gross Link: https://lore.kernel.org/r/20231016131348.1734721-1-marmarek@invisiblethingslab.com Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- drivers/xen/xen-pciback/conf_space.c | 19 +++++++++++------ .../xen/xen-pciback/conf_space_capability.c | 8 ++++++- drivers/xen/xen-pciback/conf_space_header.c | 21 +++---------------- 3 files changed, 23 insertions(+), 25 deletions(-) diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c index 059de92aea7d0..d47eee6c51435 100644 --- a/drivers/xen/xen-pciback/conf_space.c +++ b/drivers/xen/xen-pciback/conf_space.c @@ -288,12 +288,6 @@ int xen_pcibk_get_interrupt_type(struct pci_dev *dev) u16 val; int ret = 0; - err = pci_read_config_word(dev, PCI_COMMAND, &val); - if (err) - return err; - if (!(val & PCI_COMMAND_INTX_DISABLE)) - ret |= INTERRUPT_TYPE_INTX; - /* * Do not trust dev->msi(x)_enabled here, as enabling could be done * bypassing the pci_*msi* functions, by the qemu. @@ -316,6 +310,19 @@ int xen_pcibk_get_interrupt_type(struct pci_dev *dev) if (val & PCI_MSIX_FLAGS_ENABLE) ret |= INTERRUPT_TYPE_MSIX; } + + /* + * PCIe spec says device cannot use INTx if MSI/MSI-X is enabled, + * so check for INTx only when both are disabled. + */ + if (!ret) { + err = pci_read_config_word(dev, PCI_COMMAND, &val); + if (err) + return err; + if (!(val & PCI_COMMAND_INTX_DISABLE)) + ret |= INTERRUPT_TYPE_INTX; + } + return ret ?: INTERRUPT_TYPE_NONE; } diff --git a/drivers/xen/xen-pciback/conf_space_capability.c b/drivers/xen/xen-pciback/conf_space_capability.c index 097316a741268..1948a9700c8fa 100644 --- a/drivers/xen/xen-pciback/conf_space_capability.c +++ b/drivers/xen/xen-pciback/conf_space_capability.c @@ -236,10 +236,16 @@ static int msi_msix_flags_write(struct pci_dev *dev, int offset, u16 new_value, return PCIBIOS_SET_FAILED; if (new_value & field_config->enable_bit) { - /* don't allow enabling together with other interrupt types */ + /* + * Don't allow enabling together with other interrupt type, but do + * allow enabling MSI(-X) while INTx is still active to please Linuxes + * MSI(-X) startup sequence. It is safe to do, as according to PCI + * spec, device with enabled MSI(-X) shouldn't use INTx. + */ int int_type = xen_pcibk_get_interrupt_type(dev); if (int_type == INTERRUPT_TYPE_NONE || + int_type == INTERRUPT_TYPE_INTX || int_type == field_config->int_type) goto write; return PCIBIOS_SET_FAILED; diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c index ac45cdc38e859..fcaa050d692d2 100644 --- a/drivers/xen/xen-pciback/conf_space_header.c +++ b/drivers/xen/xen-pciback/conf_space_header.c @@ -104,24 +104,9 @@ static int command_write(struct pci_dev *dev, int offset, u16 value, void *data) pci_clear_mwi(dev); } - if (dev_data && dev_data->allow_interrupt_control) { - if ((cmd->val ^ value) & PCI_COMMAND_INTX_DISABLE) { - if (value & PCI_COMMAND_INTX_DISABLE) { - pci_intx(dev, 0); - } else { - /* Do not allow enabling INTx together with MSI or MSI-X. */ - switch (xen_pcibk_get_interrupt_type(dev)) { - case INTERRUPT_TYPE_NONE: - pci_intx(dev, 1); - break; - case INTERRUPT_TYPE_INTX: - break; - default: - return PCIBIOS_SET_FAILED; - } - } - } - } + if (dev_data && dev_data->allow_interrupt_control && + ((cmd->val ^ value) & PCI_COMMAND_INTX_DISABLE)) + pci_intx(dev, !(value & PCI_COMMAND_INTX_DISABLE)); cmd->val = value; -- 2.42.0