Commit c55fa78b authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/pci: Add xen_[find|register|unregister]_device_domain_owner functions. 



When the Xen PCI backend is told to enable or disable MSI/MSI-X functions,
the initial domain performs these operations. The initial domain needs
to know which domain (guest) is going to use the PCI device so when it
makes the appropiate hypercall to retrieve the MSI/MSI-X vector it will
also assign the PCI device to the appropiate domain (guest).

This boils down to us needing a mechanism to find, set and unset the domain
id that will be using the device.

[v2: EXPORT_SYMBOL -> EXPORT_SYMBOL_GPL.]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent a6360dd3

arch/x86/include/asm/xen/pci.h

+16 −0
Original line number Diff line number Diff line
@@ -15,10 +15,26 @@ static inline int pci_xen_hvm_init(void) 
#endif

#if defined(CONFIG_XEN_DOM0)

void __init xen_setup_pirqs(void);

int xen_find_device_domain_owner(struct pci_dev *dev);

int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);

int xen_unregister_device_domain_owner(struct pci_dev *dev);

#else

static inline void __init xen_setup_pirqs(void)

{

}

static inline int xen_find_device_domain_owner(struct pci_dev *dev)

{

	return -1;

}

static inline int xen_register_device_domain_owner(struct pci_dev *dev,

						   uint16_t domain)

{

	return -1;

}

static inline int xen_unregister_device_domain_owner(struct pci_dev *dev)

{

	return -1;

}

#endif



#if defined(CONFIG_PCI_MSI)

arch/x86/pci/xen.c

+73 −0
Original line number Diff line number Diff line
@@ -461,3 +461,76 @@ void __init xen_setup_pirqs(void) 
	}

}

#endif



struct xen_device_domain_owner {

	domid_t domain;

	struct pci_dev *dev;

	struct list_head list;

};



static DEFINE_SPINLOCK(dev_domain_list_spinlock);

static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);



static struct xen_device_domain_owner *find_device(struct pci_dev *dev)

{

	struct xen_device_domain_owner *owner;



	list_for_each_entry(owner, &dev_domain_list, list) {

		if (owner->dev == dev)

			return owner;

	}

	return NULL;

}



int xen_find_device_domain_owner(struct pci_dev *dev)

{

	struct xen_device_domain_owner *owner;

	int domain = -ENODEV;



	spin_lock(&dev_domain_list_spinlock);

	owner = find_device(dev);

	if (owner)

		domain = owner->domain;

	spin_unlock(&dev_domain_list_spinlock);

	return domain;

}

EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);



int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)

{

	struct xen_device_domain_owner *owner;



	owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);

	if (!owner)

		return -ENODEV;



	spin_lock(&dev_domain_list_spinlock);

	if (find_device(dev)) {

		spin_unlock(&dev_domain_list_spinlock);

		kfree(owner);

		return -EEXIST;

	}

	owner->domain = domain;

	owner->dev = dev;

	list_add_tail(&owner->list, &dev_domain_list);

	spin_unlock(&dev_domain_list_spinlock);

	return 0;

}

EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);



int xen_unregister_device_domain_owner(struct pci_dev *dev)

{

	struct xen_device_domain_owner *owner;



	spin_lock(&dev_domain_list_spinlock);

	owner = find_device(dev);

	if (!owner) {

		spin_unlock(&dev_domain_list_spinlock);

		return -ENODEV;

	}

	list_del(&owner->list);

	spin_unlock(&dev_domain_list_spinlock);

	kfree(owner);

	return 0;

}

EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);

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