Re: [PATCH] add tpm_xenu.ko: Xen Virtual TPM frontend driver

[Matthew Fioravante <matthew.fioravante@jhuapl.edu>]

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On 11/06/2012 02:39 PM, Konrad Rzeszutek Wilk wrote:
> On Mon, Nov 05, 2012 at 10:09:57AM -0500, Matthew Fioravante wrote:
>> This patch ports the xen vtpm frontend driver for linux
>> from the linux-2.6.18-xen.hg tree to linux-stable.
> So how does on test it ? Set it up? Use it? Is there some documentation
> about it - if so it should be in the patch description.
Thats actually a question I had. To use this driver now you have to use 
my vtpm mini-os domains which are currently being evaluated in the 
xen-devel mailing list. Once they are accepted I will submit a 
documentation update to the Xen tree.

Whats the best practice for documentation in this case? All in xen? Some 
linux/some xen? If the latter, how much goes in linux and where?
>
> I did a very very cursory look at it, see some of the comments.
>
>>
>> +
>> +
>> +static inline struct transmission *transmission_alloc(void)
>> +{
>> +     return kzalloc(sizeof(struct transmission), GFP_ATOMIC);
>> +}
>> +
>> +     static unsigned char *
>
> That is very weird tabbing? Did you run this patch through
> scripts/checkpatch.pl ?
Wow thats ugly. I ran the check script and it looks like it didn't pick 
this up. For some reason my editor wants to autoindent like that.
Fixed.
>
>> +
>> +static const struct file_operations vtpm_ops = {
>> +     .owner = THIS_MODULE,
>> +     .llseek = no_llseek,
>> +     .open = tpm_open,
>> +     .read = tpm_read,
>> +     .write = tpm_write,
>> +     .release = tpm_release,
>> +};
>> +
>> +static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
>> +static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
>> +static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
>> +static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
>> +static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
>> +static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
>> +             NULL);
>> +static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
>> +static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
>> +
>> +static struct attribute *vtpm_attrs[] = {
>> +     &dev_attr_pubek.attr,
>> +     &dev_attr_pcrs.attr,
>> +     &dev_attr_enabled.attr,
>> +     &dev_attr_active.attr,
>> +     &dev_attr_owned.attr,
>> +     &dev_attr_temp_deactivated.attr,
>> +     &dev_attr_caps.attr,
>> +     &dev_attr_cancel.attr,
>> +     NULL,
> So are these going to show up in SysFS? If so, there should also be
> a corresponding file in Documentation/.../sysfs/something.
These are similar to the entries made by the other tpm drivers. I don't 
see any documentation about those either. TPM maintainers, any guidance 
there?
>
>> +#include "tpm.h"
>> +#include "tpm_vtpm.h"
>> +
>> +#undef DEBUG
>> +
>> +#define GRANT_INVALID_REF 0
> Interesting. The 0 grant value is actually a valid one. I think you
> want (-1ULL).
Is it?
drivers/block/xen-blkfront.c and
drivers/net/xen-netfront.c

do the exact same thing
>> +
>> +     init_tpm_xenbus();
>> +     return 0;
>> +}
>> +
>> +
>> +module_init(tpmif_init);
> no module_exit?
Will fix



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