Re: [Xen-devel] [VTD][PATCH] Don't allow assigning the same device twice without release the first assignment

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

That's a lot better. I'll take the Xen portion but the tools changes need
more work:

The PCI-string parsing code cannot be placed in xc_private.[ch] and then
exported outside the library. Also using strtok() is invalid as it is not
thread-safe. You should use strtok_r() instead. I think you can get rid of
pci_count() altogether and have first_bdf/next_bdf return a boolean whether
they have reached the end of the string or not (strtok_r will return NULL
when the last token has been parsed). Then the caller would use them
something like:
 for (done = first_bdf(); !done; done = next_bdf())

Given the small amount of code for first_bdf/next_bdf, and given that
pci_count can be got rid of entirely, I would just duplicate that simple
strtok code in both the python wrapper and ioemu. I wouldn't add that rather
specific parsing code to libxc.

Please fix up and re-spin the tools part of the patch.

 -- Keir

On 18/10/07 02:51, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:

> Keir,
> 
> Resend the patch. This patch is implemented according to your
> suggestion. Asssigns device in xend before starting ioemu, and add the
> check on DOMCTL_assign_device hypercall. Thanks.
> 
> -- Weidong
> 
> Keir Fraser wrote:
>> On 16/10/07 03:04, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:
>> 
>>>> The DOMCTL_assign_device should check whether the device is already
>>>> assigned. This has the benefit that it can atomically
>>>> check-and-allocate, under the domctl lock.
>>>> 
>>>> You'll have to work out how to propagate DOMCTL_assign_device
>>>> failure to the user. Either you have to get the error out of ioemu,
>>>> or perhaps you can assign the device in xend before starting ioemu.
>>> 
>>> Yes, adding the check on DOMCTL_assign_device is simple, but I didn't
>>> find a good way to propagate DOMCTL_assign_device failure to user.
>>> This patch adds the check in xend before starting ioemu. In addtion,
>>> adding the check in Xend can prompt user on the screen when the
>>> device has already been assigned. Thanks.
>> 
>> Well, that's too bad because I won't take the original patch. Why
>> can't the device be assigned by xend?
>> 
>>  -- Keir
> 



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