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 B7E98C19F28 for ; Wed, 27 Jul 2022 17:03:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233140AbiG0RDt (ORCPT ); Wed, 27 Jul 2022 13:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232385AbiG0RDQ (ORCPT ); Wed, 27 Jul 2022 13:03:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D9636D9C2; Wed, 27 Jul 2022 09:38:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CFBCF60B68; Wed, 27 Jul 2022 16:38:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBA54C433C1; Wed, 27 Jul 2022 16:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939917; bh=Pyg9mJW8D9qeURa9xoUZFw426rog098zh/2yXBWjFrU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WWwpuI/o5d2ahiPMyIidmw0Lcsc9TdiVXg5ken4hpT+H/09FtW5zY4aG/Wnu6lNH1 VZ77esVB5b2NYoPqk3UiBBgEsANdyLUVz7eHY+qFEpiFKWC+n9W73hrBD56AYWabL4 UBq+tobMil0OqxSwUZlP3EJWUS+ctY/qEuX22lRI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Jeffrey Hugo , Dexuan Cui , Wei Liu , Carl Vanderlip Subject: [PATCH 5.15 010/201] PCI: hv: Fix multi-MSI to allow more than one MSI vector Date: Wed, 27 Jul 2022 18:08:34 +0200 Message-Id: <20220727161027.367763215@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161026.977588183@linuxfoundation.org> References: <20220727161026.977588183@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeffrey Hugo commit 08e61e861a0e47e5e1a3fb78406afd6b0cea6b6d upstream. If the allocation of multiple MSI vectors for multi-MSI fails in the core PCI framework, the framework will retry the allocation as a single MSI vector, assuming that meets the min_vecs specified by the requesting driver. Hyper-V advertises that multi-MSI is supported, but reuses the VECTOR domain to implement that for x86. The VECTOR domain does not support multi-MSI, so the alloc will always fail and fallback to a single MSI allocation. In short, Hyper-V advertises a capability it does not implement. Hyper-V can support multi-MSI because it coordinates with the hypervisor to map the MSIs in the IOMMU's interrupt remapper, which is something the VECTOR domain does not have. Therefore the fix is simple - copy what the x86 IOMMU drivers (AMD/Intel-IR) do by removing X86_IRQ_ALLOC_CONTIGUOUS_VECTORS after calling the VECTOR domain's pci_msi_prepare(). 5.15 backport - adds the hv_msi_prepare wrapper function Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Signed-off-by: Jeffrey Hugo Reviewed-by: Dexuan Cui Link: https://lore.kernel.org/r/1649856981-14649-1-git-send-email-quic_jhugo@quicinc.com Signed-off-by: Wei Liu Signed-off-by: Carl Vanderlip Signed-off-by: Greg Kroah-Hartman --- drivers/pci/controller/pci-hyperv.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1204,6 +1204,21 @@ static void hv_irq_mask(struct irq_data pci_msi_mask_irq(data); } +static int hv_msi_prepare(struct irq_domain *domain, struct device *dev, + int nvec, msi_alloc_info_t *info) +{ + int ret = pci_msi_prepare(domain, dev, nvec, info); + + /* + * By using the interrupt remapper in the hypervisor IOMMU, contiguous + * CPU vectors is not needed for multi-MSI + */ + if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI) + info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS; + + return ret; +} + /** * hv_irq_unmask() - "Unmask" the IRQ by setting its current * affinity. @@ -1601,7 +1616,7 @@ static struct irq_chip hv_msi_irq_chip = }; static struct msi_domain_ops hv_msi_ops = { - .msi_prepare = pci_msi_prepare, + .msi_prepare = hv_msi_prepare, .msi_free = hv_msi_free, };