linux-kernel - Re: [PATCH 04/14] platform/x86/intel/ifs: Remove image loading during init

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Date:   Mon, 24 Oct 2022 17:41:38 -0700
From:   "Joseph, Jithu" <jithu.joseph@...el.com>
To:     Sohil Mehta <sohil.mehta@...el.com>
CC:     <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <dave.hansen@...ux.intel.com>, <x86@...nel.org>, <hpa@...or.com>,
        <gregkh@...uxfoundation.org>, <ashok.raj@...el.com>,
        <tony.luck@...el.com>, <linux-kernel@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>, <patches@...ts.linux.dev>,
        <ravi.v.shankar@...el.com>, <thiago.macieira@...el.com>,
        <athenas.jimenez.gonzalez@...el.com>, <markgross@...nel.org>,
        <hdegoede@...hat.com>
Subject: Re: [PATCH 04/14] platform/x86/intel/ifs: Remove image loading during
 init



On 10/24/2022 4:50 PM, Sohil Mehta wrote:
> On 10/21/2022 1:34 PM, Jithu Joseph wrote:
>> Existing implementation loads IFS test image during the driver
>> init flow.
>>
>> Dropping test image loading from the init path improves
>> module load time.
>>
>> Prior to starting IFS tests, the user has to load one of
>> the IFS test images by writing to the current_batch sysfs file.
>>
> 
> The kernel is still unaware of the 'current_batch' sysfs file. It will be introduced in patch 12. You can avoid the reference here.

ok will remove the current_batch reference and mention that user has to explicitly load test images

> 
>> Removing IFS test image  loading during init also allows us to
>> make ifs_sem static as it is used only within sysfs.c.
>>
> 
> Does something like this sound better?
> 
> IFS test image is unnecessarily loaded during driver initialization. The user has to load one when starting the tests.
> 
> Drop image loading during ifs_init() and improve module load time. As a consequence, make ifs_sem static as it is only used within sysfs.c

Will adopt this, Thanks

> 
>> diff --git a/drivers/platform/x86/intel/ifs/core.c b/drivers/platform/x86/intel/ifs/core.c
>> index 27204e3d674d..5fb7f655c291 100644
>> --- a/drivers/platform/x86/intel/ifs/core.c
>> +++ b/drivers/platform/x86/intel/ifs/core.c
>> @@ -51,12 +51,8 @@ static int __init ifs_init(void)
>>       ifs_device.misc.groups = ifs_get_groups();
>>         if ((msrval & BIT(ifs_device.data.integrity_cap_bit)) &&
> 
> Is there a reason to store the integrity cap constant in the device.data global structure?
> 
> .data = {
>     .integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
> },

This was originally added so that, when future additional tests are supported by the driver, support can be checked using  the same if ((msrval & BIT(ifs_device.data.integrity_cap_bit)
Different tests would have different integrity_cap_bit assigned in the ifs_device[] array  (today it is just a single element and not an array

Note that the current series doesn't introduce this



Jithu