Re: [PATCH] xen-pciback: allow compiling on other archs than x86

[Juergen Gross <jgross@suse.com>]

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On 17.09.21 15:01, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
> 
> Xen-pciback driver was designed to be built for x86 only. But it
> can also be used by other architectures, e.g. Arm.
> Re-structure the driver in a way that it can be built for other
> platforms as well.
> 
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
> Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
> 
> ---
> Tested on Arm and x86.
> ---
>   arch/x86/include/asm/xen/pci.h     | 24 ----------
>   arch/x86/pci/xen.c                 | 74 +----------------------------
>   drivers/xen/Kconfig                |  2 +-
>   drivers/xen/events/events_base.c   |  1 +
>   drivers/xen/pci.c                  | 75 ++++++++++++++++++++++++++++++
>   drivers/xen/xen-pciback/pci_stub.c |  3 +-
>   drivers/xen/xen-pciback/xenbus.c   |  2 +-
>   include/xen/pci.h                  | 34 ++++++++++++++
>   8 files changed, 115 insertions(+), 100 deletions(-)
>   create mode 100644 include/xen/pci.h
> 
> diff --git a/arch/x86/include/asm/xen/pci.h b/arch/x86/include/asm/xen/pci.h
> index 3506d8c598c1..9ff7b49bca08 100644
> --- a/arch/x86/include/asm/xen/pci.h
> +++ b/arch/x86/include/asm/xen/pci.h
> @@ -14,30 +14,6 @@ static inline int pci_xen_hvm_init(void)
>   	return -1;
>   }
>   #endif
> -#if defined(CONFIG_XEN_DOM0)
> -int __init pci_xen_initial_domain(void);

Why are you removing this prototype? It is X86 specific.

> -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 int __init pci_xen_initial_domain(void)
> -{
> -	return -1;
> -}
> -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)
>   #if defined(CONFIG_PCI_XEN)
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 3d41a09c2c14..4a45b0bf9ae4 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -23,6 +23,7 @@
>   
>   #include <xen/features.h>
>   #include <xen/events.h>
> +#include <xen/pci.h>
>   #include <asm/xen/pci.h>
>   #include <asm/xen/cpuid.h>
>   #include <asm/apic.h>
> @@ -583,77 +584,4 @@ int __init pci_xen_initial_domain(void)
>   	}
>   	return 0;
>   }
> -
> -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);
>   #endif
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index a37eb52fb401..057ddf61ef61 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -182,7 +182,7 @@ config SWIOTLB_XEN
>   
>   config XEN_PCIDEV_BACKEND
>   	tristate "Xen PCI-device backend driver"
> -	depends on PCI && X86 && XEN
> +	depends on PCI && XEN
>   	depends on XEN_BACKEND
>   	default m
>   	help
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index a78704ae3618..35493ff0d146 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -65,6 +65,7 @@
>   #include <xen/interface/vcpu.h>
>   #include <xen/xenbus.h>
>   #include <asm/hw_irq.h>
> +#include <xen/pci.h>

This wouldn't be needed if you'd let the pci_xen_initial_domain()
prototype where it has been.


Juergen

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