Re: [PATCH 2/3] libxl: attach PCI device to qemu only after setting pciback/pcifront

[Wei Liu <wei.liu2@citrix.com>]

On Tue, Oct 18, 2016 at 03:53:32AM +0200, Marek Marczykowski-Górecki wrote:
> When qemu is running in stubdomain, handling "pci-ins" command will fail
> if pcifront is not initialized already. Fix this by sending such command
> only after confirming that pciback/front is running.
> 
> It is possible to handle this case in mini-os code, by delaying
> "pci-ins" handling until pcifront_thread finishes devices discovery. But
> the same problem most likely will apply to any other stubdomain
> implementations when they come (Rumprun, Linux) - so better handle this
> at libxl level.
> 
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

Mostly some coding style issues.

> ---
>  tools/libxl/libxl_pci.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
> index 2ae1bc4..3805d30 100644
> --- a/tools/libxl/libxl_pci.c
> +++ b/tools/libxl/libxl_pci.c
> @@ -1195,6 +1195,7 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid, libxl_device_pci *pcide
>  {
>      libxl_ctx *ctx = libxl__gc_owner(gc);
>      unsigned int orig_vdev, pfunc_mask;
> +    char *be_path;
>      libxl_device_pci *assigned;
>      int num_assigned, i, rc;
>      int stubdomid = 0;
> @@ -1249,6 +1250,14 @@ int libxl__device_pci_add(libxl__gc *gc, uint32_t domid, libxl_device_pci *pcide
>          rc = do_pci_add(gc, stubdomid, &pcidev_s, 0);
>          if ( rc )
>              goto out;
> +        /* wait for the device actually being connected, otherwise device model
> +         * running there will fail to find the device */

Hmm... I don't think we have written down style requirement for code
comment, but I would like this comment to be formatted a bit.

        /* Wait for the device actually being connected, otherwise device model
         * running there will fail to find the device. */

That is to capitalise the first word and make it a proper sentence.

> +        be_path = libxl__sprintf(gc, "%s/backend/pci/%d/0",
> +                libxl__xs_get_dompath(gc, 0), stubdomid);
> +        rc = libxl__wait_for_backend(gc, be_path,
> +                    GCSPRINTF("%d", XenbusStateConnected));

Please indent this a bit.

> +        if ( rc )

Not really your problem. This file is ridden with such style violation.
Can you please remove the space before and after "rc"?

Wei.

> +            goto out;
>      }
>  
>      orig_vdev = pcidev->vdevfn & ~7U;
> -- 
> 2.5.5
> 

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