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From: Alexander Graf <graf@amazon.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Greg KH <gregkh@linuxfoundation.org>
Cc: Andra Paraschiv <andraprs@amazon.com>,
	<linux-kernel@vger.kernel.org>,
	Anthony Liguori <aliguori@amazon.com>,
	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, 9 Jun 2020 12:47:27 +0200	[thread overview]
Message-ID: <f83838cf-8a20-8c9c-be87-4c6625563bd6@amazon.de> (raw)
In-Reply-To: <a37b0156c076d3875f906e970071cb230e526df1.camel@kernel.crashing.org>



On 01.06.20 05:04, Benjamin Herrenschmidt wrote:
> 
> 
> On Thu, 2020-05-28 at 15:12 +0200, Greg KH wrote:
>> So at runtime, after all is booted and up and going, you just ripped
>> cores out from under someone's feet?  :)
>>
>> And the code really handles writing to that value while the module is
>> already loaded and up and running?  At a quick glance, it didn't seem
>> like it would handle that very well as it only is checked at ne_init()
>> time.
>>
>> Or am I missing something?
>>
>> Anyway, yes, if you can dynamically do this at runtime, that's great,
>> but it feels ackward to me to rely on one configuration thing as a
>> module parameter, and everything else through the ioctl interface.
>> Unification would seem to be a good thing, right?
> 
> I personally still prefer a sysfs file :) I really don't like module
> parameters as a way to do such things.

I think we're going in circles :).

A module parameter initialized with module_param_cb gives us a sysfs 
file that can also have a default parameter set through easily available 
tooling.

The ioctl has two downsides:

   1) It relies on an external application
   2) The permission check would be strictly limited to CAP_ADMIN, sysfs 
files can have different permissions

So I fail to see how a module parameter is *not* giving both of you and 
me what we want? Of course only if it implements the callback. It was 
missing that and apologize for that oversight.


Alex



Amazon Development Center Germany GmbH
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  reply	other threads:[~2020-06-09 10:50 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-25 22:13 [PATCH v3 00/18] Add support for Nitro Enclaves Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 01/18] nitro_enclaves: Add ioctl interface definition Andra Paraschiv
2020-05-27  8:49   ` Stefan Hajnoczi
2020-05-28 18:05     ` Paraschiv, Andra-Irina
2020-06-01  3:02     ` Benjamin Herrenschmidt
2020-06-01  7:20       ` Paraschiv, Andra-Irina
2020-06-05  8:15         ` Stefan Hajnoczi
2020-06-05 15:39           ` Paraschiv, Andra-Irina
2020-05-25 22:13 ` [PATCH v3 02/18] nitro_enclaves: Define the PCI device interface Andra Paraschiv
2020-05-26  6:44   ` Greg KH
2020-05-26 17:01     ` Paraschiv, Andra-Irina
2020-05-26 22:21       ` Greg KH
2020-05-28 16:37         ` Paraschiv, Andra-Irina
2020-06-01  2:59         ` Benjamin Herrenschmidt
2020-06-01  7:07           ` Paraschiv, Andra-Irina
2020-06-01  2:53       ` Benjamin Herrenschmidt
2020-05-25 22:13 ` [PATCH v3 03/18] nitro_enclaves: Define enclave info for internal bookkeeping Andra Paraschiv
2020-05-26  6:46   ` Greg KH
2020-05-26 17:20     ` Paraschiv, Andra-Irina
2020-05-25 22:13 ` [PATCH v3 04/18] nitro_enclaves: Init PCI device driver Andra Paraschiv
2020-05-26  6:48   ` Greg KH
2020-05-26 18:35     ` Paraschiv, Andra-Irina
2020-05-26 22:19       ` Greg KH
2020-05-28 16:26         ` Paraschiv, Andra-Irina
2020-06-01  2:55       ` Benjamin Herrenschmidt
2020-06-01  6:42         ` Paraschiv, Andra-Irina
2020-05-25 22:13 ` [PATCH v3 05/18] nitro_enclaves: Handle PCI device command requests Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 06/18] nitro_enclaves: Handle out-of-band PCI device events Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 07/18] nitro_enclaves: Init misc device providing the ioctl interface Andra Paraschiv
2020-05-26  6:51   ` Greg KH
2020-05-26 11:42     ` Alexander Graf
2020-05-26 12:33       ` Greg KH
2020-05-26 12:44         ` Alexander Graf
2020-05-26 13:17           ` Greg KH
2020-05-26 13:44             ` Alexander Graf
2020-05-26 22:24               ` Greg KH
2020-05-28 13:01                 ` Alexander Graf
2020-05-28 13:12                   ` Greg KH
2020-05-28 17:06                     ` Paraschiv, Andra-Irina
2020-06-01  3:04                     ` Benjamin Herrenschmidt
2020-06-09 10:47                       ` Alexander Graf [this message]
2020-06-01  3:01                 ` Benjamin Herrenschmidt
2020-06-01  2:51           ` Benjamin Herrenschmidt
2020-05-26 13:40         ` Paraschiv, Andra-Irina
2020-06-01  2:47     ` Benjamin Herrenschmidt
2020-06-01  5:48       ` Greg KH
2020-05-25 22:13 ` [PATCH v3 08/18] nitro_enclaves: Add logic for enclave vm creation Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 09/18] nitro_enclaves: Add logic for enclave vcpu creation Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 10/18] nitro_enclaves: Add logic for enclave image load metadata Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 11/18] nitro_enclaves: Add logic for enclave memory region set Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 12/18] nitro_enclaves: Add logic for enclave start Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 13/18] nitro_enclaves: Add logic for enclave termination Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 14/18] nitro_enclaves: Add Kconfig for the Nitro Enclaves driver Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 15/18] nitro_enclaves: Add Makefile " Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 16/18] nitro_enclaves: Add sample for ioctl interface usage Andra Paraschiv
2020-05-26  6:52   ` Greg KH
2020-05-25 22:13 ` [PATCH v3 17/18] nitro_enclaves: Add overview documentation Andra Paraschiv
2020-05-25 22:13 ` [PATCH v3 18/18] MAINTAINERS: Add entry for the Nitro Enclaves driver Andra Paraschiv

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