[PATCH] Hotadd of IOAPICs described in static MADT

[Rui Wang]

For IOAPICs described in static MADT, we already called __mp_register_ioapic()
in arch_early_irq_init(). During boot PCI root hotadd will call it again and
will find it already registered, thus register_ioapic() won't add it to the
ioapic_list. Subsequent hot-removal will also fail because it is not
found on the
ioapic_list.

Signed-off-by: Rui Wang <rui.y.wang@xxxxxxxxx>
---
 arch/x86/kernel/apic/io_apic.c |    4 +++-
 drivers/pci/ioapic.c           |    3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index fb9bf06..15ab9f1 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3956,8 +3956,10 @@ int __mp_register_ioapic(int id, u32 address,
u32 gsi_base, bool hotadd)

        /* already registered ? */
        idx = __mp_find_ioapic(gsi_base);
-       if (idx >= 0)
+       if (idx >= 0) {
+               ret = -EEXIST;
                goto out;
+       }

        idx = find_first_zero_bit(ioapics_mask, MAX_IO_APICS);
        if (idx >= MAX_IO_APICS) {
diff --git a/drivers/pci/ioapic.c b/drivers/pci/ioapic.c
index 41f7c69..83b002b 100644
--- a/drivers/pci/ioapic.c
+++ b/drivers/pci/ioapic.c
@@ -126,7 +126,8 @@ static void handle_ioapic_add(acpi_handle handle,
struct pci_dev **pdev,
                }
        }

-       if (acpi_register_ioapic(handle, res->start, gsi_base)) {
+       ret = acpi_register_ioapic(handle, res->start, gsi_base);
+       if (ret && ret != -EEXIST) {
                if (dev)
                        goto exit_release;
                return;
-- 
1.7.3.4


Thanks
Rui


>
> -	pci_set_drvdata(dev, ioapic);
> -	dev_info(&dev->dev, "%s at %pR, GSI %u\n", type, res, ioapic->gsi_base);
> -	return 0;
> +	pr_info("%s %s %s at %pR, GSI %u\n",
> +		dev_name(&dev->dev), objname, type,
> +		res, gsi_base);
> +
> +	*pdev = dev;
> +	*pgsi_base = gsi_base;
> +	return;
>
>  exit_release:
>  	pci_release_region(dev, 0);
>  exit_disable:
>  	pci_disable_device(dev);
> -exit_free:
> -	kfree(ioapic);
> -	return -ENODEV;
> +exit_put:
> +	pci_dev_put(dev);
>  }
>
> -static void ioapic_remove(struct pci_dev *dev)
> +static void handle_ioapic_remove(acpi_handle handle, struct pci_dev *dev,
> +				  u32 gsi_base)
>  {
> -	struct ioapic *ioapic = pci_get_drvdata(dev);
> +	acpi_unregister_ioapic(handle, gsi_base);
>
> -	acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base);
>  	pci_release_region(dev, 0);
>  	pci_disable_device(dev);
> -	kfree(ioapic);
> +	pci_dev_put(dev);
>  }
>
> +static acpi_status register_ioapic(acpi_handle handle, u32 lvl,
> +					void *context, void **rv)
> +{
> +	acpi_handle root_handle = context;
> +	struct pci_dev *pdev;
> +	u32 gsi_base;
> +	struct acpi_pci_ioapic *ioapic;
>
> -static DEFINE_PCI_DEVICE_TABLE(ioapic_devices) = {
> -	{ PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOAPIC, ~0) },
> -	{ PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOXAPIC, ~0) },
> -	{ }
> -};
> -MODULE_DEVICE_TABLE(pci, ioapic_devices);
> +	handle_ioapic_add(handle, &pdev, &gsi_base);
> +	if (!gsi_base)
> +		return AE_OK;
>
> -static struct pci_driver ioapic_driver = {
> -	.name		= "ioapic",
> -	.id_table	= ioapic_devices,
> -	.probe		= ioapic_probe,
> -	.remove		= ioapic_remove,
> -};
> +	ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL);
> +	if (!ioapic) {
> +		pr_err("%s: cannot allocate memory\n", __func__);
> +		handle_ioapic_remove(root_handle, pdev, gsi_base);
> +		return AE_OK;
> +	}
> +	ioapic->root_handle = root_handle;
> +	ioapic->pdev = pdev;
> +	ioapic->gsi_base = gsi_base;
> +
> +	mutex_lock(&ioapic_list_lock);
> +	list_add(&ioapic->list, &ioapic_list);
> +	mutex_unlock(&ioapic_list_lock);
> +
> +	return AE_OK;
> +}
>
> -static int __init ioapic_init(void)
> +void acpi_pci_ioapic_add(struct acpi_pci_root *root)
>  {
> -	return pci_register_driver(&ioapic_driver);
> +	acpi_status status;
> +
> +	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
> +				     (u32)1, register_ioapic, NULL,
> +				     root->device->handle,
> +				     NULL);
> +	if (ACPI_FAILURE(status))
> +		pr_err("%s: register_ioapic failure - %d", __func__, status);
>  }
> -module_init(ioapic_init);
>
> -MODULE_LICENSE("GPL");
> +void acpi_pci_ioapic_remove(struct acpi_pci_root *root)
> +{
> +	struct acpi_pci_ioapic *ioapic, *tmp;
> +
> +	mutex_lock(&ioapic_list_lock);
> +	list_for_each_entry_safe(ioapic, tmp, &ioapic_list, list) {
> +		if (root->device->handle != ioapic->root_handle)
> +			continue;
> +		list_del(&ioapic->list);
> +		handle_ioapic_remove(ioapic->root_handle, ioapic->pdev,
> +					ioapic->gsi_base);
> +		kfree(ioapic);
> +	}
> +	mutex_unlock(&ioapic_list_lock);
> +}
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index 1704479..b2a2ced 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -69,6 +69,14 @@ static inline void acpiphp_remove_slots(struct pci_bus
> *bus) { }
>  static inline void acpiphp_check_host_bridge(acpi_handle handle) { }
>  #endif
>
> +#ifdef CONFIG_PCI_IOAPIC
> +void acpi_pci_ioapic_add(struct acpi_pci_root *root);
> +void acpi_pci_ioapic_remove(struct acpi_pci_root *root);
> +#else
> +static inline void acpi_pci_ioapic_add(struct acpi_pci_root *root) { }
> +static inline void acpi_pci_ioapic_remove(struct acpi_pci_root *root) { }
> +#endif
> +
>  #else	/* CONFIG_ACPI */
>  static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
>  static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
> --
> 1.8.1.4
>
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