Re: [RFC XEN PATCH v12 6/7] tools: Add new function to get gsi from dev

[Anthony PERARD <anthony.perard@vates.tech>]

On Mon, Jul 08, 2024 at 07:41:23PM +0800, Jiqian Chen wrote:
> diff --git a/tools/libs/ctrl/xc_physdev.c b/tools/libs/ctrl/xc_physdev.c
> index e9fcd755fa62..54edb0f3c0dc 100644
> --- a/tools/libs/ctrl/xc_physdev.c
> +++ b/tools/libs/ctrl/xc_physdev.c
> @@ -111,3 +111,38 @@ int xc_physdev_unmap_pirq(xc_interface *xch,
>      return rc;
>  }
>  
> +int xc_physdev_gsi_from_pcidev(xc_interface *xch, uint32_t sbdf)
> +{
> +    int rc = -1;
> +
> +#if defined(__linux__)
> +    int fd;
> +    privcmd_gsi_from_pcidev_t dev_gsi = {
> +        .sbdf = sbdf,
> +        .gsi = 0,
> +    };
> +
> +    fd = open("/dev/xen/privcmd", O_RDWR);


You could reuse the already opened fd from libxencall:
    xencall_fd(xch->xcall)

> +
> +    if (fd < 0 && (errno == ENOENT || errno == ENXIO || errno == ENODEV)) {
> +        /* Fallback to /proc/xen/privcmd */
> +        fd = open("/proc/xen/privcmd", O_RDWR);
> +    }
> +
> +    if (fd < 0) {
> +        PERROR("Could not obtain handle on privileged command interface");
> +        return rc;
> +    }
> +
> +    rc = ioctl(fd, IOCTL_PRIVCMD_GSI_FROM_PCIDEV, &dev_gsi);

I think this would be better implemented in Linux only C file instead of
using #define. There's already "xc_linux.c" which is probably good
enough to be used here.

Implementation for other OS would just set errno to ENOSYS and
return -1.


-- 

Anthony Perard | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech