Re: [RFC V1 1/7] genirq/msi: Differentiate between various MSI based interrupts

From: Bjorn Helgaas
Date: Thu Sep 26 2019 - 17:50:10 EST

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On Thu, Sep 12, 2019 at 06:32:02PM -0700, Megha Dey wrote:
> Since a device can support both MSI-X and IMS interrupts simultaneously,
> do away with is_msix and introduce a new enum msi_desc_tag to
> differentiate between the various types of msi_descs.
>
> Signed-off-by: Megha Dey <megha.dey@xxxxxxxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> # for drivers/pci/msi.c

> ---
> arch/mips/pci/msi-xlp.c | 2 +-
> arch/s390/pci/pci_irq.c | 2 +-
> arch/x86/kernel/apic/msi.c | 2 +-
> arch/x86/pci/xen.c | 2 +-
> drivers/pci/msi.c | 19 ++++++++++---------
> include/linux/msi.h | 11 ++++++++++-
> kernel/irq/msi.c | 2 +-
> 7 files changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/arch/mips/pci/msi-xlp.c b/arch/mips/pci/msi-xlp.c
> index bb14335..0f06ad1 100644
> --- a/arch/mips/pci/msi-xlp.c
> +++ b/arch/mips/pci/msi-xlp.c
> @@ -457,7 +457,7 @@ int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
> node = slot / 8;
> lnkbase = nlm_get_pcie_base(node, link);
>
> - if (desc->msi_attrib.is_msix)
> + if (desc->tag == IRQ_MSI_TAG_MSIX)
> return xlp_setup_msix(lnkbase, node, link, desc);
> else
> return xlp_setup_msi(lnkbase, node, link, desc);
> diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c
> index d80616a..1938582 100644
> --- a/arch/s390/pci/pci_irq.c
> +++ b/arch/s390/pci/pci_irq.c
> @@ -332,7 +332,7 @@ void arch_teardown_msi_irqs(struct pci_dev *pdev)
> for_each_pci_msi_entry(msi, pdev) {
> if (!msi->irq)
> continue;
> - if (msi->msi_attrib.is_msix)
> + if (msi->tag == IRQ_MSI_TAG_MSIX)
> __pci_msix_desc_mask_irq(msi, 1);
> else
> __pci_msi_desc_mask_irq(msi, 1, 1);
> diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
> index 7f75334..435bcda 100644
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -98,7 +98,7 @@ int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
>
> init_irq_alloc_info(arg, NULL);
> arg->msi_dev = pdev;
> - if (desc->msi_attrib.is_msix) {
> + if (desc->tag == IRQ_MSI_TAG_MSIX) {
> arg->type = X86_IRQ_ALLOC_TYPE_MSIX;
> } else {
> arg->type = X86_IRQ_ALLOC_TYPE_MSI;
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 91220cc..5e850b8 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -382,7 +382,7 @@ static void xen_teardown_msi_irqs(struct pci_dev *dev)
> struct msi_desc *msidesc;
>
> msidesc = first_pci_msi_entry(dev);
> - if (msidesc->msi_attrib.is_msix)
> + if (msidesc->tag == IRQ_MSI_TAG_MSIX)
> xen_pci_frontend_disable_msix(dev);
> else
> xen_pci_frontend_disable_msi(dev);
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 0884bed..8a05416 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -235,7 +235,7 @@ static void msi_set_mask_bit(struct irq_data *data, u32 flag)
> {
> struct msi_desc *desc = irq_data_get_msi_desc(data);
>
> - if (desc->msi_attrib.is_msix) {
> + if (desc->tag == IRQ_MSI_TAG_MSIX) {
> msix_mask_irq(desc, flag);
> readl(desc->mask_base); /* Flush write to device */
> } else {
> @@ -278,7 +278,7 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
>
> BUG_ON(dev->current_state != PCI_D0);
>
> - if (entry->msi_attrib.is_msix) {
> + if (entry->tag == IRQ_MSI_TAG_MSIX) {
> void __iomem *base = pci_msix_desc_addr(entry);
>
> if (!base) {
> @@ -313,7 +313,7 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
>
> if (dev->current_state != PCI_D0 || pci_dev_is_disconnected(dev)) {
> /* Don't touch the hardware now */
> - } else if (entry->msi_attrib.is_msix) {
> + } else if (entry->tag == IRQ_MSI_TAG_MSIX) {
> void __iomem *base = pci_msix_desc_addr(entry);
>
> if (!base)
> @@ -376,7 +376,7 @@ static void free_msi_irqs(struct pci_dev *dev)
> pci_msi_teardown_msi_irqs(dev);
>
> list_for_each_entry_safe(entry, tmp, msi_list, list) {
> - if (entry->msi_attrib.is_msix) {
> + if (entry->tag == IRQ_MSI_TAG_MSIX) {
> if (list_is_last(&entry->list, msi_list))
> iounmap(entry->mask_base);
> }
> @@ -471,7 +471,7 @@ static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
> entry = irq_get_msi_desc(irq);
> if (entry)
> return sprintf(buf, "%s\n",
> - entry->msi_attrib.is_msix ? "msix" : "msi");
> + (entry->tag == IRQ_MSI_TAG_MSIX) ? "msix" : "msi");
>
> return -ENODEV;
> }
> @@ -570,7 +570,7 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
>
> pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
>
> - entry->msi_attrib.is_msix = 0;
> + entry->tag = IRQ_MSI_TAG_MSI;
> entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
> entry->msi_attrib.is_virtual = 0;
> entry->msi_attrib.entry_nr = 0;
> @@ -714,7 +714,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
> goto out;
> }
>
> - entry->msi_attrib.is_msix = 1;
> + entry->tag = IRQ_MSI_TAG_MSIX;
> entry->msi_attrib.is_64 = 1;
> if (entries)
> entry->msi_attrib.entry_nr = entries[i].entry;
> @@ -1380,7 +1380,7 @@ irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
>
> static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
> {
> - return !desc->msi_attrib.is_msix && desc->nvec_used > 1;
> + return (desc->tag == IRQ_MSI_TAG_MSI) && desc->nvec_used > 1;
> }
>
> /**
> @@ -1404,7 +1404,8 @@ int pci_msi_domain_check_cap(struct irq_domain *domain,
> if (pci_msi_desc_is_multi_msi(desc) &&
> !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
> return 1;
> - else if (desc->msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
> + else if ((desc->tag == IRQ_MSI_TAG_MSIX) &&
> + !(info->flags & MSI_FLAG_PCI_MSIX))
> return -ENOTSUPP;
>
> return 0;
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 8ad679e..22591b6 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -55,6 +55,15 @@ struct ti_sci_inta_msi_desc {
> u16 dev_index;
> };
>
> +enum msi_desc_tags {
> + IRQ_MSI_TAG_MSI,
> + IRQ_MSI_TAG_MSIX,
> + IRQ_MSI_TAG_IMS,
> + IRQ_MSI_TAG_PLAT,
> + IRQ_MSI_TAG_FSL,
> + IRQ_MSI_TAG_SCI,
> +};
> +
> /**
> * struct msi_desc - Descriptor structure for MSI based interrupts
> * @list: List head for management
> @@ -90,6 +99,7 @@ struct msi_desc {
> struct device *dev;
> struct msi_msg msg;
> struct irq_affinity_desc *affinity;
> + enum msi_desc_tags tag;
> #ifdef CONFIG_IRQ_MSI_IOMMU
> const void *iommu_cookie;
> #endif
> @@ -102,7 +112,6 @@ struct msi_desc {
> struct {
> u32 masked;
> struct {
> - u8 is_msix : 1;
> u8 multiple : 3;
> u8 multi_cap : 3;
> u8 maskbit : 1;
> diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
> index ad26fbc..0819395 100644
> --- a/kernel/irq/msi.c
> +++ b/kernel/irq/msi.c
> @@ -384,7 +384,7 @@ static bool msi_check_reservation_mode(struct irq_domain *domain,
> * masking and MSI does so when the maskbit is set.
> */
> desc = first_msi_entry(dev);
> - return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
> + return (desc->tag == IRQ_MSI_TAG_MSIX) || desc->msi_attrib.maskbit;
> }
>
> /**
> --
> 2.7.4
>

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