Re: [patch V2 08/31] PCI/MSI: Use msi_add_msi_desc()

Bjorn Helgaas
2021-12-07T21:07:27Z

On Mon, Dec 06, 2021 at 11:51:15PM +0100, Thomas Gleixner wrote:
> Simplify the allocation of MSI descriptors by using msi_add_msi_desc()
> which moves the storage handling to core code and prepares for dynamic
> extension of the MSI-X vector space.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
> drivers/pci/msi/msi.c | 122 ++++++++++++++++++++++++--------------------------
> 1 file changed, 59 insertions(+), 63 deletions(-)
>
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -340,45 +340,51 @@ void pci_restore_msi_state(struct pci_de
> }
> EXPORT_SYMBOL_GPL(pci_restore_msi_state);
>
> -static struct msi_desc *
> -msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks)
> +static int msi_setup_msi_desc(struct pci_dev *dev, int nvec,
> + struct irq_affinity_desc *masks)
> {
> - struct msi_desc *entry;
> + struct msi_desc desc;
> unsigned long prop;
> u16 control;
> + int ret;
>
> /* MSI Entry Initialization */
> - entry = alloc_msi_entry(&dev->dev, nvec, masks);
> - if (!entry)
> - return NULL;
> + memset(&desc, 0, sizeof(desc));
>
> pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
> /* Lies, damned lies, and MSIs */
> if (dev->dev_flags & PCI_DEV_FLAGS_HAS_MSI_MASKING)
> control |= PCI_MSI_FLAGS_MASKBIT;
> + /* Respect XEN's mask disabling */
> + if (pci_msi_ignore_mask)
> + control &= ~PCI_MSI_FLAGS_MASKBIT;
>
> - entry->pci.msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
> - entry->pci.msi_attrib.can_mask = !pci_msi_ignore_mask &&
> - !!(control & PCI_MSI_FLAGS_MASKBIT);
> - entry->pci.msi_attrib.default_irq = dev->irq;
> - entry->pci.msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> - entry->pci.msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
> + desc.nvec_used = nvec;
> + desc.pci.msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
> + desc.pci.msi_attrib.can_mask = !!(control & PCI_MSI_FLAGS_MASKBIT);
> + desc.pci.msi_attrib.default_irq = dev->irq;
> + desc.pci.msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
> + desc.pci.msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
> + desc.affinity = masks;
>
> if (control & PCI_MSI_FLAGS_64BIT)
> - entry->pci.mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> + desc.pci.mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
> else
> - entry->pci.mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
> + desc.pci.mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
>
> /* Save the initial mask status */
> - if (entry->pci.msi_attrib.can_mask)
> - pci_read_config_dword(dev, entry->pci.mask_pos, &entry->pci.msi_mask);
> + if (desc.pci.msi_attrib.can_mask)
> + pci_read_config_dword(dev, desc.pci.mask_pos, &desc.pci.msi_mask);
>
> - prop = MSI_PROP_PCI_MSI;
> - if (entry->pci.msi_attrib.is_64)
> - prop |= MSI_PROP_64BIT;
> - msi_device_set_properties(&dev->dev, prop);
> + ret = msi_add_msi_desc(&dev->dev, &desc);
> + if (!ret) {
> + prop = MSI_PROP_PCI_MSI;
> + if (desc.pci.msi_attrib.is_64)
> + prop |= MSI_PROP_64BIT;
> + msi_device_set_properties(&dev->dev, prop);
> + }
>
> - return entry;
> + return ret;
> }
>
> static int msi_verify_entries(struct pci_dev *dev)
> @@ -423,17 +429,14 @@ static int msi_capability_init(struct pc
> masks = irq_create_affinity_masks(nvec, affd);
>
> msi_lock_descs(&dev->dev);
> - entry = msi_setup_entry(dev, nvec, masks);
> - if (!entry) {
> - ret = -ENOMEM;
> + ret = msi_setup_msi_desc(dev, nvec, masks);
> + if (ret)
> goto unlock;
> - }
>
> /* All MSIs are unmasked by default; mask them all */
> + entry = first_pci_msi_entry(dev);
> pci_msi_mask(entry, msi_multi_mask(entry));
>
> - list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));
> -
> /* Configure MSI capability structure */
> ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
> if (ret)
> @@ -482,49 +485,40 @@ static void __iomem *msix_map_region(str
> return ioremap(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
> }
>
> -static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
> - struct msix_entry *entries, int nvec,
> - struct irq_affinity_desc *masks)
> +static int msix_setup_msi_descs(struct pci_dev *dev, void __iomem *base,
> + struct msix_entry *entries, int nvec,
> + struct irq_affinity_desc *masks)
> {
> - int i, vec_count = pci_msix_vec_count(dev);
> + int ret = 0, i, vec_count = pci_msix_vec_count(dev);
> struct irq_affinity_desc *curmsk;
> - struct msi_desc *entry;
> + struct msi_desc desc;
> void __iomem *addr;
>
> - for (i = 0, curmsk = masks; i < nvec; i++) {
> - entry = alloc_msi_entry(&dev->dev, 1, curmsk);
> - if (!entry) {
> - /* No enough memory. Don't try again */
> - return -ENOMEM;
> - }
> -
> - entry->pci.msi_attrib.is_msix = 1;
> - entry->pci.msi_attrib.is_64 = 1;
> -
> - if (entries)
> - entry->msi_index = entries[i].entry;
> - else
> - entry->msi_index = i;
> -
> - entry->pci.msi_attrib.is_virtual = entry->msi_index >= vec_count;
> -
> - entry->pci.msi_attrib.can_mask = !pci_msi_ignore_mask &&
> - !entry->pci.msi_attrib.is_virtual;
> -
> - entry->pci.msi_attrib.default_irq = dev->irq;
> - entry->pci.mask_base = base;
> + memset(&desc, 0, sizeof(desc));
>
> - if (entry->pci.msi_attrib.can_mask) {
> - addr = pci_msix_desc_addr(entry);
> - entry->pci.msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
> + desc.nvec_used = 1;
> + desc.pci.msi_attrib.is_msix = 1;
> + desc.pci.msi_attrib.is_64 = 1;
> + desc.pci.msi_attrib.default_irq = dev->irq;
> + desc.pci.mask_base = base;
> +
> + for (i = 0, curmsk = masks; i < nvec; i++, curmsk++) {
> + desc.msi_index = entries ? entries[i].entry : i;
> + desc.affinity = masks ? curmsk : NULL;
> + desc.pci.msi_attrib.is_virtual = desc.msi_index >= vec_count;
> + desc.pci.msi_attrib.can_mask = !pci_msi_ignore_mask &&
> + !desc.pci.msi_attrib.is_virtual;
> +
> + if (!desc.pci.msi_attrib.can_mask) {
> + addr = pci_msix_desc_addr(&desc);
> + desc.pci.msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
> }
>
> - list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));
> - if (masks)
> - curmsk++;
> + ret = msi_add_msi_desc(&dev->dev, &desc);
> + if (ret)
> + break;
> }
> - msi_device_set_properties(&dev->dev, MSI_PROP_PCI_MSIX | MSI_PROP_64BIT);
> - return 0;
> + return ret;
> }
>
> static void msix_update_entries(struct pci_dev *dev, struct msix_entry *entries)
> @@ -562,10 +556,12 @@ static int msix_setup_interrupts(struct
> masks = irq_create_affinity_masks(nvec, affd);
>
> msi_lock_descs(&dev->dev);
> - ret = msix_setup_entries(dev, base, entries, nvec, masks);
> + ret = msix_setup_msi_descs(dev, base, entries, nvec, masks);
> if (ret)
> goto out_free;
>
> + msi_device_set_properties(&dev->dev, MSI_PROP_PCI_MSIX | MSI_PROP_64BIT);
> +
> ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
> if (ret)
> goto out_free;
>