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 59F83C77B7D for ; Wed, 10 May 2023 10:48:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236272AbjEJKsv (ORCPT ); Wed, 10 May 2023 06:48:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229656AbjEJKst (ORCPT ); Wed, 10 May 2023 06:48:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7692D3C3F; Wed, 10 May 2023 03:48:45 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AEBFD1063; Wed, 10 May 2023 03:49:29 -0700 (PDT) Received: from [10.57.83.77] (unknown [10.57.83.77]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8F7D43F5A1; Wed, 10 May 2023 03:48:42 -0700 (PDT) Message-ID: <38cb8b93-6f10-c269-e574-613ae6a9dd87@arm.com> Date: Wed, 10 May 2023 11:48:38 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH v3 07/11] irqchip/riscv-imsic: Improve IOMMU DMA support Content-Language: en-GB To: Anup Patel , Palmer Dabbelt , Paul Walmsley , Thomas Gleixner , Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Joerg Roedel , Will Deacon , Frank Rowand Cc: Atish Patra , Andrew Jones , Anup Patel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, iommu@lists.linux.dev, Vincent Chen References: <20230508142842.854564-1-apatel@ventanamicro.com> <20230508142842.854564-8-apatel@ventanamicro.com> From: Robin Murphy In-Reply-To: <20230508142842.854564-8-apatel@ventanamicro.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-05-08 15:28, Anup Patel wrote: > We have a separate RISC-V IMSIC MSI address for each CPU so changing > MSI (or IRQ) affinity results in re-programming of MSI address in > the PCIe (or platform) device. > > Currently, the iommu_dma_prepare_msi() is called only once at the > time of IRQ allocation so IOMMU DMA domain will only have mapping > for one MSI page. This means iommu_dma_compose_msi_msg() called > by imsic_irq_compose_msi_msg() will always use the same MSI page > irrespective to target CPU MSI address. In other words, changing > MSI (or IRQ) affinity for device using IOMMU DMA domain will not > work. > > To address above issue, we do the following: > 1) Map MSI pages for all CPUs in imsic_irq_domain_alloc() > using iommu_dma_prepare_msi(). > 2) Add a new iommu_dma_select_msi() API to select a specific > MSI page from a set of already mapped MSI pages. > 3) Use iommu_dma_select_msi() to select a specific MSI page > before calling iommu_dma_compose_msi_msg() in > imsic_irq_compose_msi_msg(). The high-level design is that prepare ensures any necessary page mappings exist, then compose retrieves the appropriate page for the given message. I think it generalises well enough without needing a new op, it just means that caching a single page in the msi_desc up-front no longer fits, so that wants tweaking to allow compose to do a more general lookup. Thanks, Robin. > Reported-by: Vincent Chen > Signed-off-by: Anup Patel > --- > drivers/iommu/dma-iommu.c | 38 +++++++++++++++++++++++++++++++ > drivers/irqchip/irq-riscv-imsic.c | 27 ++++++++++++---------- > include/linux/iommu.h | 6 +++++ > 3 files changed, 59 insertions(+), 12 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 7a9f0b0bddbd..07782c77a6eb 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -1677,6 +1677,44 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) > return 0; > } > > +/** > + * iommu_dma_select_msi() - Select a MSI page from a set of > + * already mapped MSI pages in the IOMMU domain. > + * > + * @desc: MSI descriptor prepared by iommu_dma_prepare_msi() > + * @msi_addr: physical address of the MSI page to be selected > + * > + * Return: 0 on success or negative error code if the select failed. > + */ > +int iommu_dma_select_msi(struct msi_desc *desc, phys_addr_t msi_addr) > +{ > + struct device *dev = msi_desc_to_dev(desc); > + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); > + const struct iommu_dma_msi_page *msi_page; > + struct iommu_dma_cookie *cookie; > + > + if (!domain || !domain->iova_cookie) { > + desc->iommu_cookie = NULL; > + return 0; > + } > + > + cookie = domain->iova_cookie; > + msi_addr &= ~(phys_addr_t)(cookie_msi_granule(cookie) - 1); > + > + msi_page = msi_desc_get_iommu_cookie(desc); > + if (msi_page && msi_page->phys == msi_addr) > + return 0; > + > + list_for_each_entry(msi_page, &cookie->msi_page_list, list) { > + if (msi_page->phys == msi_addr) { > + msi_desc_set_iommu_cookie(desc, msi_page); > + return 0; > + } > + } > + > + return -ENOENT; > +} > + > /** > * iommu_dma_compose_msi_msg() - Apply translation to an MSI message > * @desc: MSI descriptor prepared by iommu_dma_prepare_msi() > diff --git a/drivers/irqchip/irq-riscv-imsic.c b/drivers/irqchip/irq-riscv-imsic.c > index 30247c84a6b0..ec61c599e0c5 100644 > --- a/drivers/irqchip/irq-riscv-imsic.c > +++ b/drivers/irqchip/irq-riscv-imsic.c > @@ -446,6 +446,10 @@ static void imsic_irq_compose_msi_msg(struct irq_data *d, > if (WARN_ON(err)) > return; > > + err = iommu_dma_select_msi(desc, msi_addr); > + if (WARN_ON(err)) > + return; > + > msg->address_hi = upper_32_bits(msi_addr); > msg->address_lo = lower_32_bits(msi_addr); > msg->data = d->hwirq; > @@ -493,11 +497,18 @@ static int imsic_irq_domain_alloc(struct irq_domain *domain, > int i, hwirq, err = 0; > unsigned int cpu; > > - err = imsic_get_cpu(&imsic->lmask, false, &cpu); > - if (err) > - return err; > + /* Map MSI address of all CPUs */ > + for_each_cpu(cpu, &imsic->lmask) { > + err = imsic_cpu_page_phys(cpu, 0, &msi_addr); > + if (err) > + return err; > > - err = imsic_cpu_page_phys(cpu, 0, &msi_addr); > + err = iommu_dma_prepare_msi(info->desc, msi_addr); > + if (err) > + return err; > + } > + > + err = imsic_get_cpu(&imsic->lmask, false, &cpu); > if (err) > return err; > > @@ -505,10 +516,6 @@ static int imsic_irq_domain_alloc(struct irq_domain *domain, > if (hwirq < 0) > return hwirq; > > - err = iommu_dma_prepare_msi(info->desc, msi_addr); > - if (err) > - goto fail; > - > for (i = 0; i < nr_irqs; i++) { > imsic_id_set_target(hwirq + i, cpu); > irq_domain_set_info(domain, virq + i, hwirq + i, > @@ -528,10 +535,6 @@ static int imsic_irq_domain_alloc(struct irq_domain *domain, > } > > return 0; > - > -fail: > - imsic_ids_free(hwirq, get_count_order(nr_irqs)); > - return err; > } > > static void imsic_irq_domain_free(struct irq_domain *domain, > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index e8c9a7da1060..41e8613832ab 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -1117,6 +1117,7 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit); > int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base); > > int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr); > +int iommu_dma_select_msi(struct msi_desc *desc, phys_addr_t msi_addr); > void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg); > > #else /* CONFIG_IOMMU_DMA */ > @@ -1138,6 +1139,11 @@ static inline int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_a > return 0; > } > > +static inline int iommu_dma_select_msi(struct msi_desc *desc, phys_addr_t msi_addr) > +{ > + return 0; > +} > + > static inline void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg) > { > }