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Message-ID: <20221116202254.GA1134096@bhelgaas>
Date: Wed, 16 Nov 2022 14:22:54 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Marc Zyngier <maz@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jason Gunthorpe <jgg@...lanox.com>,
Dave Jiang <dave.jiang@...el.com>,
Alex Williamson <alex.williamson@...hat.com>,
Kevin Tian <kevin.tian@...el.com>,
Dan Williams <dan.j.williams@...el.com>,
Logan Gunthorpe <logang@...tatee.com>,
Ashok Raj <ashok.raj@...el.com>, Jon Mason <jdmason@...zu.us>,
Allen Hubbe <allenbh@...il.com>,
"Ahmed S. Darwish" <darwi@...utronix.de>,
Reinette Chatre <reinette.chatre@...el.com>
Subject: Re: [patch 12/33] PCI/MSI: Add support for per device MSI[X] domains
Comment below uses [-X] (not [X]).
On Fri, Nov 11, 2022 at 02:58:30PM +0100, Thomas Gleixner wrote:
> Provide a template and the necessary callbacks to create PCI/MSI and
> PCI/MSI-X domains.
>
> The domains are created when MSI or MSI-X is enabled. The domains lifetime
domain's
> is either the device life time or in case that e.g. MSI-X was tried first
lifetime (as used above)
> and failed, then the MSI-X domain is removed and a MSI domain is created as
> both are mutually exclusive and reside in the default domain id slot of the
> per device domain pointer array.
ID?
> Also expand pci_msi_domain_supports() to handle feature checks correctly
> even in the case that the per device domain was not yet created by checking
> the features supported by the MSI parent.
>
> Add the necessary setup calls into the MSI and MSI-X enable code path.
> These setup calls are backwards compatible. They return success when there
> is no parent domain found, which means the existing global domains or the
> legacy allocation path keep just working.
>
> Co-developed-by: Ahmed S. Darwish <darwi@...utronix.de>
> Signed-off-by: Ahmed S. Darwish <darwi@...utronix.de>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
A couple typos below.
> ---
> drivers/pci/msi/irqdomain.c | 188 +++++++++++++++++++++++++++++++++++++++++++-
> drivers/pci/msi/msi.c | 16 +++
> drivers/pci/msi/msi.h | 2
> 3 files changed, 201 insertions(+), 5 deletions(-)
>
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -139,6 +139,170 @@ struct irq_domain *pci_msi_create_irq_do
> }
> EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
>
> +/*
> + * Per device MSI[-X] domain functionality
> + */
> +static void pci_device_domain_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
> +{
> + arg->desc = desc;
> + arg->hwirq = desc->msi_index;
> +}
> +
> +static void pci_mask_msi(struct irq_data *data)
> +{
> + struct msi_desc *desc = irq_data_get_msi_desc(data);
> +
> + pci_msi_mask(desc, BIT(data->irq - desc->irq));
> +}
> +
> +static void pci_unmask_msi(struct irq_data *data)
> +{
> + struct msi_desc *desc = irq_data_get_msi_desc(data);
> +
> + pci_msi_unmask(desc, BIT(data->irq - desc->irq));
> +}
> +
> +#ifdef CONFIG_GENERIC_IRQ_RESERVATION_MODE
> +# define MSI_REACTIVATE MSI_FLAG_MUST_REACTIVATE
> +#else
> +# define MSI_REACTIVATE 0
> +#endif
> +
> +#define MSI_COMMON_FLAGS (MSI_FLAG_FREE_MSI_DESCS | \
> + MSI_FLAG_ACTIVATE_EARLY | \
> + MSI_FLAG_DEV_SYSFS | \
> + MSI_REACTIVATE)
> +
> +static struct msi_domain_template pci_msi_template = {
> + .chip = {
> + .name = "PCI-MSI",
> + .irq_mask = pci_mask_msi,
> + .irq_unmask = pci_unmask_msi,
> + .irq_write_msi_msg = pci_msi_domain_write_msg,
> + .flags = IRQCHIP_ONESHOT_SAFE,
> + },
> +
> + .ops = {
> + .set_desc = pci_device_domain_set_desc,
> + },
> +
> + .info = {
> + .flags = MSI_COMMON_FLAGS | MSI_FLAG_MULTI_PCI_MSI,
> + .bus_token = DOMAIN_BUS_PCI_DEVICE_MSI,
> + },
> +};
> +
> +static void pci_mask_msix(struct irq_data *data)
> +{
> + pci_msix_mask(irq_data_get_msi_desc(data));
> +}
> +
> +static void pci_unmask_msix(struct irq_data *data)
> +{
> + pci_msix_unmask(irq_data_get_msi_desc(data));
> +}
> +
> +static struct msi_domain_template pci_msix_template = {
> + .chip = {
> + .name = "PCI-MSIX",
> + .irq_mask = pci_mask_msix,
> + .irq_unmask = pci_unmask_msix,
> + .irq_write_msi_msg = pci_msi_domain_write_msg,
> + .flags = IRQCHIP_ONESHOT_SAFE,
> + },
> +
> + .ops = {
> + .set_desc = pci_device_domain_set_desc,
> + },
> +
> + .info = {
> + .flags = MSI_COMMON_FLAGS | MSI_FLAG_PCI_MSIX,
> + .bus_token = DOMAIN_BUS_PCI_DEVICE_MSIX,
> + },
> +};
> +
> +static bool pci_match_device_domain(struct pci_dev *pdev, enum irq_domain_bus_token bus_token)
> +{
> + return msi_match_device_irq_domain(&pdev->dev, MSI_DEFAULT_DOMAIN, bus_token);
> +}
> +
> +static bool pci_create_device_domain(struct pci_dev *pdev, struct msi_domain_template *tmpl,
> + unsigned int hwsize)
> +{
> + struct irq_domain *domain = dev_get_msi_domain(&pdev->dev);
> +
> + if (!domain || !irq_domain_is_msi_parent(domain))
> + return true;
> +
> + return msi_create_device_irq_domain(&pdev->dev, MSI_DEFAULT_DOMAIN, tmpl,
> + hwsize, NULL, NULL);
> +}
> +
> +/**
> + * pci_setup_msi_device_domain - Setup a device MSI interrupt domain
> + * @pdev: The PCI device to create the domain on
> + *
> + * Return:
> + * True when:
> + * - The device does not have a MSI parent irq domain associated,
> + * which keeps the legacy architecture specific and the global
> + * PCI/MSI domain models working
> + * - The MSI domain exists already
> + * - The MSI domain was successfully allocated
> + * False when:
> + * - MSI-X is enabled
> + * - The domain creation fails.
> + *
> + * The created MSI domain is preserved until:
> + * - The device is removed
> + * - MSI is disabled and a MSI-X domain is created
> + */
> +bool pci_setup_msi_device_domain(struct pci_dev *pdev)
> +{
> + if (WARN_ON_ONCE(pdev->msix_enabled))
> + return false;
> +
> + if (pci_match_device_domain(pdev, DOMAIN_BUS_PCI_DEVICE_MSI))
> + return true;
> + if (pci_match_device_domain(pdev, DOMAIN_BUS_PCI_DEVICE_MSIX))
> + msi_remove_device_irq_domain(&pdev->dev, MSI_DEFAULT_DOMAIN);
> +
> + return pci_create_device_domain(pdev, &pci_msi_template, 1);
> +}
> +
> +/**
> + * pci_setup_msix_device_domain - Setup a device MSI-X interrupt domain
> + * @pdev: The PCI device to create the domain on
> + * @hwsize: The size of the MSI-X vector table
> + *
> + * Return:
> + * True when:
> + * - The device does not have a MSI parent irq domain associated,
> + * which keeps the legacy architecture specific and the global
> + * PCI/MSI domain models working
> + * - The MSI-X domain exists already
> + * - The MSI-X domain was successfully allocated
> + * False when:
> + * - MSI is enabled
> + * - The domain creation fails.
> + *
> + * The created MSI-X domain is preserved until:
> + * - The device is removed
> + * - MSI-X is disabled and a MSI domain is created
> + */
> +bool pci_setup_msix_device_domain(struct pci_dev *pdev, unsigned int hwsize)
> +{
> + if (WARN_ON_ONCE(pdev->msix_enabled))
> + return false;
> +
> + if (pci_match_device_domain(pdev, DOMAIN_BUS_PCI_DEVICE_MSIX))
> + return true;
> + if (pci_match_device_domain(pdev, DOMAIN_BUS_PCI_DEVICE_MSI))
> + msi_remove_device_irq_domain(&pdev->dev, MSI_DEFAULT_DOMAIN);
> +
> + return pci_create_device_domain(pdev, &pci_msix_template, hwsize);
> +}
> +
> /**
> * pci_msi_domain_supports - Check for support of a particular feature flag
> * @pdev: The PCI device to operate on
> @@ -152,13 +316,33 @@ bool pci_msi_domain_supports(struct pci_
> {
> struct msi_domain_info *info;
> struct irq_domain *domain;
> + unsigned int supported;
>
> domain = dev_get_msi_domain(&pdev->dev);
>
> if (!domain || !irq_domain_is_hierarchy(domain))
> return mode == ALLOW_LEGACY;
> - info = domain->host_data;
> - return (info->flags & feature_mask) == feature_mask;
> +
> + if (!irq_domain_is_msi_parent(domain)) {
> + /*
> + * For "global" PCI/MSI interrupt domains the associated
> + * msi_domain_info::flags is the authoritive source of
authoritative
> + * information.
> + */
> + info = domain->host_data;
> + supported = info->flags;
> + } else {
> + /*
> + * For MSI parent domains the supported feature set
> + * is avaliable in the parent ops. This makes checks
available
> + * possible before actually instantiating the
> + * per device domain because the parent is never
> + * expanding the PCI/MSI functionality.
> + */
> + supported = domain->msi_parent_ops->supported_flags;
> + }
> +
> + return (supported & feature_mask) == feature_mask;
> }
>
> /*
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -436,6 +436,9 @@ int __pci_enable_msi_range(struct pci_de
> if (rc)
> return rc;
>
> + if (!pci_setup_msi_device_domain(dev))
> + return -ENODEV;
> +
> for (;;) {
> if (affd) {
> nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
> @@ -787,9 +790,13 @@ int __pci_enable_msix_range(struct pci_d
> if (!pci_msix_validate_entries(dev, entries, nvec, hwsize))
> return -EINVAL;
>
> - /* PCI_IRQ_VIRTUAL is a horrible hack! */
> - if (nvec > hwsize && !(flags & PCI_IRQ_VIRTUAL))
> - nvec = hwsize;
> + if (hwsize < nvec) {
> + /* Keep the IRQ virtual hackery working */
> + if (flags & PCI_IRQ_VIRTUAL)
> + hwsize = nvec;
> + else
> + nvec = hwsize;
> + }
>
> if (nvec < minvec)
> return -ENOSPC;
> @@ -798,6 +805,9 @@ int __pci_enable_msix_range(struct pci_d
> if (rc)
> return rc;
>
> + if (!pci_setup_msix_device_domain(dev, hwsize))
> + return -ENODEV;
> +
> for (;;) {
> if (affd) {
> nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
> --- a/drivers/pci/msi/msi.h
> +++ b/drivers/pci/msi/msi.h
> @@ -105,6 +105,8 @@ enum support_mode {
> };
>
> bool pci_msi_domain_supports(struct pci_dev *dev, unsigned int feature_mask, enum support_mode mode);
> +bool pci_setup_msi_device_domain(struct pci_dev *pdev);
> +bool pci_setup_msix_device_domain(struct pci_dev *pdev, unsigned int hwsize);
>
> /* Legacy (!IRQDOMAIN) fallbacks */
>
>
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