linux-kernel - Re: [PATCH RFC] pass write value to in

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4A40A5D5.4080208@redhat.com>
Date:	Tue, 23 Jun 2009 12:52:21 +0300
From:	Avi Kivity <avi@...hat.com>
To:	"Michael S. Tsirkin" <mst@...hat.com>
CC:	Gregory Haskins <ghaskins@...ell.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, mtosatti@...hat.com,
	paulmck@...ux.vnet.ibm.com, markmc@...hat.com
Subject: Re: [PATCH RFC] pass write value to in_range pointers

On 06/22/2009 07:08 PM, Michael S. Tsirkin wrote:
> On Mon, Jun 22, 2009 at 11:45:00AM -0400, Gregory Haskins wrote:
>    
>> Michael S. Tsirkin wrote:
>>      
>>> It seems that a lot of complexity and trickiness with iosignalfd is
>>> handling the group/item relationship, which comes about because kvm does
>>> not currently let a device on the bus claim a write transaction based on the
>>> value written.  This could be greatly simplified if the value written
>>> was passed to the in_range check for write operation.  We could then
>>> simply make each kvm_iosignalfd a device on the bus.
>>>
>>> What does everyone think of the following lightly tested patch?
>>>
>>>        
>> Hi Michael,
>>    Its interesting, but I am not convinced its necessary.  We created the
>> group/item layout because iosignalfds are unique in that they are
>> probably the only IO device that wants to do some kind of address
>> aliasing.
>>      
>
> We actually already have aliasing: is_write flag is used for this
> purpose. Actually, it's possible to remove is_write by passing
> a null pointer in write_val for reads. I like this a bit less as
> the code generated is less compact ... Avi, what do you think?
>    

Greg, won't Michael's patch eliminate a big chunk from your iosignalfd 
patches?  Seems like a win to me.

> One is enough :)
> Seriously, do you see that this saves you all of RCU, linked lists and
> counters? You don't need to keep track of iofds, you don't need to
> implement your own lookup logic - you just use the kvm device
> and that's it.
>
>    

Yup.

-- 
error compiling committee.c: too many arguments to function

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/