Date: Tue, 14 Jan 2014 17:20:46 +0100 From: =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= <roger.pau@citrix.com> To: Julien Grall <julien.grall@citrix.com> Cc: jhb@freebsd.org, xen-devel@lists.xen.org, freebsd-xen@freebsd.org, freebsd-current@freebsd.org, kib@freebsd.org, gibbs@freebsd.org Subject: Re: [PATCH v10 14/20] xen: introduce xenpv bus and a dummy pvcpu device Message-ID: <52D563DE.1020207@citrix.com> In-Reply-To: <52D5625D.7030702@citrix.com> References: <1389711582-66908-1-git-send-email-roger.pau@citrix.com> <1389711582-66908-15-git-send-email-roger.pau@citrix.com> <52D55AB4.4010504@linaro.org> <52D560EB.8040108@citrix.com> <52D5625D.7030702@citrix.com>
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On 14/01/14 17:14, Julien Grall wrote:
> On 01/14/2014 04:08 PM, Roger Pau Monné wrote:
>> On 14/01/14 16:41, Julien Grall wrote:
>>> On 01/14/2014 02:59 PM, Roger Pau Monne wrote:
>>>> +static int
>>>> +xenpv_attach(device_t dev)
>>>> +{
>>>> + device_t child;
>>>> +
>>>> + if (xen_hvm_domain()) {
>>>> + device_t xenpci;
>>>> + devclass_t dc;
>>>> +
>>>> + /* Make sure xenpci has been attached */
>>>> + dc = devclass_find("xenpci");
>>>> + if (dc == NULL)
>>>> + panic("unable to find xenpci devclass");
>>>> +
>>>> + xenpci = devclass_get_device(dc, 0);
>>>> + if (xenpci == NULL)
>>>> + panic("unable to find xenpci device");
>>>> +
>>>> + if (!device_is_attached(xenpci))
>>>> + panic("trying to attach xenpv before xenpci");
>>>> + }
>>>
>>> Can you use the identify method to add the xenpci device?
>>
>> I don't think so, xenpci is a pci device, it is detected and plugged by
>> the pci bus code.
>
> Oups, I though you are trying to add the device. In this case, the check
> seems pointless. In which case the xenpci couldn't exist?
It's just a "belt and suspenders", if we attach the xenpv bus without
xenpci being attached first a bunch of things are going to fail, I
though it might be best to print a clear error message about what went
wrong in order to help debug it.
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