Re: [PATCH v3 07/18] nitro_enclaves: Init misc device providing the ioctl interface - Paraschiv, Andra-Irina

From: "Paraschiv, Andra-Irina" <andraprs@amazon.com>
To: Greg KH <gregkh@linuxfoundation.org>, Alexander Graf <graf@amazon.de>
Cc: <linux-kernel@vger.kernel.org>,
	Anthony Liguori <aliguori@amazon.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Colm MacCarthaigh <colmmacc@amazon.com>,
	Bjoern Doebel <doebel@amazon.de>,
	David Woodhouse <dwmw@amazon.co.uk>,
	Frank van der Linden <fllinden@amazon.com>,
	"Martin Pohlack" <mpohlack@amazon.de>,
	Matt Wilson <msw@amazon.com>, Paolo Bonzini <pbonzini@redhat.com>,
	Balbir Singh <sblbir@amazon.com>,
	Stefano Garzarella <sgarzare@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Stewart Smith <trawets@amazon.com>,
	Uwe Dannowski <uwed@amazon.de>, <kvm@vger.kernel.org>,
	<ne-devel-upstream@amazon.com>
Subject: Re: [PATCH v3 07/18] nitro_enclaves: Init misc device providing the ioctl interface
Date: Tue, 26 May 2020 16:40:54 +0300	[thread overview]
Message-ID: <7361cea4-7e2e-3ee6-b47e-b2a8ba22c860@amazon.com> (raw)
In-Reply-To: <20200526123300.GA2798@kroah.com>

On 26/05/2020 15:33, Greg KH wrote:
> On Tue, May 26, 2020 at 01:42:41PM +0200, Alexander Graf wrote:
>>
>> On 26.05.20 08:51, Greg KH wrote:
>>> On Tue, May 26, 2020 at 01:13:23AM +0300, Andra Paraschiv wrote:
>>>> +#define NE "nitro_enclaves: "
>>> Again, no need for this.
>>>
>>>> +#define NE_DEV_NAME "nitro_enclaves"
>>> KBUILD_MODNAME?
>>>
>>>> +#define NE_IMAGE_LOAD_OFFSET (8 * 1024UL * 1024UL)
>>>> +
>>>> +static char *ne_cpus;
>>>> +module_param(ne_cpus, charp, 0644);
>>>> +MODULE_PARM_DESC(ne_cpus, "<cpu-list> - CPU pool used for Nitro Enclaves");
>>> Again, please do not do this.
>> I actually asked her to put this one in specifically.
>>
>> The concept of this parameter is very similar to isolcpus= and maxcpus= in
>> that it takes CPUs away from Linux and instead donates them to the
>> underlying hypervisor, so that it can spawn enclaves using them.
>>
>>  From an admin's point of view, this is a setting I would like to keep
>> persisted across reboots. How would this work with sysfs?
> How about just as the "initial" ioctl command to set things up?  Don't
> grab any cpu pools until asked to.  Otherwise, what happens when you
> load this module on a system that can't support it?
>
> module parameters are a major pain, you know this :)
>
>> So yes, let's give everyone in CC the change to review v3 properly first
>> before v4 goes out.
>>
>>> And get them to sign off on it too, showing they agree with the design
>>> decisions here :)
>> I would expect a Reviewed-by tag as a result from the above would satisfy
>> this? :)
> That would be most appreciated.

With regarding to reviewing, yes, the patch series went through several 
rounds before submitting it upstream.

I posted v3 shortly after v2 to have more visibility into the changelog 
for each patch in addition to the cover letter changelog. But no major 
design changes in there. :)

Thank you.

Andra

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