[libvirt] [PATCH 2/4 v2] pci: Add helper functions for sriov devices

[Stefan Berger]

On 08/12/2011 07:14 PM, Roopa Prabhu wrote:
> From: Roopa Prabhu<roprabhu at cisco.com>
>
> This patch adds the following helper functions:
> pciDeviceIsVirtualFunction: Function to check if a pci device is a sriov VF
> pciGetVirtualFunctionIndex: Function to get the VF index of a sriov VF
> pciDeviceNetName: Function to get the network device name of a pci device
> pciConfigAddressCompare: Function to compare pci config addresses
>
> Signed-off-by: Roopa Prabhu<roprabhu at cisco.com>
> Signed-off-by: Christian Benvenuti<benve at cisco.com>
> Signed-off-by: David Wang<dwang2 at cisco.com>
> ---
>   src/util/pci.c |  118 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   src/util/pci.h |   15 +++++++
>   2 files changed, 133 insertions(+), 0 deletions(-)
>
>
> diff --git a/src/util/pci.c b/src/util/pci.c
> index e017db9..558c7ae 100644
> --- a/src/util/pci.c
> +++ b/src/util/pci.c
> @@ -1875,3 +1875,121 @@ out:
>
>       return ret;
>   }
> +
> +/*
> + * returns 0 if equal and 1 if not
> + */
> +static int
> +pciConfigAddressCompare(struct pci_config_address *bdf1,
> +                        struct pci_config_address *bdf2)
> +{
> +    return !((bdf1->domain == bdf2->domain)&
> +             (bdf1->bus == bdf2->bus)&
> +             (bdf1->slot == bdf2->slot)&
> +             (bdf1->function == bdf2->function));
> +}
Would it no be more intuitive to call implement a function 
pciConfigAddressEqual and return '1' in case the addresses are equal?
> +
> +/*
> + * Returns 1 if vf device is a virtual function, 0 if not, -1 on error
> + */
> +int
> +pciDeviceIsVirtualFunctionLinux(const char *vf_sysfs_device_link)
> +{
> +    char *vf_sysfs_physfn_link = NULL;
> +    int ret = -1;
> +
> +    if (virAsprintf(&vf_sysfs_physfn_link, "%s/physfn",
> +        vf_sysfs_device_link)<  0) {
> +        virReportOOMError();
> +        return ret;
> +    }
> +
> +    ret = virFileExists(vf_sysfs_physfn_link);
> +
> +    VIR_FREE(vf_sysfs_physfn_link);
> +
> +    return ret;
> +}
> +
> +/*
> + * Returns the sriov virtual function index of vf given its pf
> + */
> +int
> +pciGetVirtualFunctionIndexLinux(const char *pf_sysfs_device_link,
> +                                const char *vf_sysfs_device_link,
> +                                int *vf_index)
> +{
> +    int ret = -1, i;
> +    unsigned int num_virt_fns = 0;
> +    struct pci_config_address *vf_bdf = NULL;
> +    struct pci_config_address **virt_fns = NULL;
> +
> +    if (pciGetPciConfigAddressFromSysfsDeviceLink(vf_sysfs_device_link,
> +&vf_bdf))
> +        return ret;
> +
> +    if (pciGetVirtualFunctionsLinux(pf_sysfs_device_link,&virt_fns,
> +&num_virt_fns)) {
> +        VIR_DEBUG("Error getting physical function's '%s' virtual_functions\n",
> +                  pf_sysfs_device_link);
> +        goto out;
> +    }
> +
> +    for (i = 0; i<  num_virt_fns; i++) {
> +         if (!pciConfigAddressCompare(vf_bdf, virt_fns[i])) {
> +             *vf_index = i;
> +             ret = 0;
> +             break;
> +         }
> +    }
> +
> +out:
> +
> +    /* free virtual functions */
> +    for (i = 0; i<  num_virt_fns; i++)
> +         VIR_FREE(virt_fns[i]);
> +
> +    VIR_FREE(vf_bdf);
> +
> +    return ret;
> +}
> +
> +/*
> + * Returns the network device name of a pci device
> + */
> +int
> +pciDeviceNetNameLinux(char *device_link_sysfs_path, char **netname)
> +{
> +     char *pcidev_sysfs_net_path = NULL;
> +     int ret = -1;
> +     DIR *dir = NULL;
> +     struct dirent *entry = NULL;
> +
> +     if (virBuildPath(&pcidev_sysfs_net_path, device_link_sysfs_path,
> +         "net") == -1) {
> +         virReportOOMError();
> +         return -1;
> +     }
> +
> +     dir = opendir(pcidev_sysfs_net_path);
> +     if (dir == NULL)
> +         goto out;
> +
> +     while ((entry = readdir(dir))) {
> +            if (!strcmp(entry->d_name, ".") ||
> +                !strcmp(entry->d_name, ".."))
> +                continue;
> +
> +            /* Assume a single directory entry */
> +            *netname = strdup(entry->d_name);
> +            ret = 0;
> +            break;
> +     }
> +
> +     closedir(dir);
> +
> +out:
> +     VIR_FREE(pcidev_sysfs_net_path);
> +
> +     return ret;
> +}
> diff --git a/src/util/pci.h b/src/util/pci.h
> index 367881e..0cdc6ec 100644
> --- a/src/util/pci.h
> +++ b/src/util/pci.h
> @@ -92,10 +92,25 @@ int pciGetVirtualFunctionsLinux(const char *sysfs_path,
>                                   struct pci_config_address ***virtual_functions,
>                                   unsigned int *num_virtual_functions);
>
> +# define pciDeviceIsVirtualFunction(v) pciDeviceIsVirtualFunctionLinux(v)
> +int pciDeviceIsVirtualFunctionLinux(const char *vf_sysfs_device_link);
> +
> +# define pciGetVirtualFunctionIndex(p,v,i) \
> +         pciGetVirtualFunctionIndexLinux(p,v,i)
> +int pciGetVirtualFunctionIndexLinux(const char *pf_sysfs_device_link,
> +                                    const char *vf_sysfs_device_link,
> +                                    int *vf_index);
> +
> +# define pciDeviceNetName(d,n) pciDeviceNetNameLinux(d,n)
> +int pciDeviceNetNameLinux(char *device_link_sysfs_path, char **netname);
> +
>   #else /* __linux__ */
>
>   #  define pciGetPhysicalFunction(s,a)
>   #  define pciGetVirtualFunctions(s,a,n)
> +#  define pciDeviceIsVirtualFunction(v)
Also here is there is code like 'if (!pciDeviceIsVirtualFunction())' it 
will be expanded to if (!) on non-Linux platforms, which is not 
compilable. Maybe an inline function in this case will do?


> +#  define pciGetVirtualFunctionIndex(p,v,i)
> +#  define pciDeviceNetNameLinux(d,n)
Same for these two also.
>   #endif
>
>
Stefan