linux-kernel - Re: [PATCH] kvm: remove in_range from kvm_io

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: <20090623155607.GB21423@redhat.com>
Date:	Tue, 23 Jun 2009 18:56:07 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Gregory Haskins <ghaskins@...ell.com>
Cc:	avi@...hat.com, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	mtosatti@...hat.com, paulmck@...ux.vnet.ibm.com, markmc@...hat.com
Subject: Re: [PATCH] kvm: remove in_range from kvm_io_device

On Tue, Jun 23, 2009 at 11:44:57AM -0400, Gregory Haskins wrote:
> >>  This proposed approach forces us into a
> >> potential O(256) algorithm in the hotpath (all MMIO/PIO exits will hit
> >> this, not just in-kernel users).  How would you address this?
> >>     
> >
> > Two ideas that come to mind:
> > - add addr/len fields to devices, use these to speed up lookup
> >   
> 
> Yep, thats what I was thinking as well.  We can have the top-level
> (group) be an rbtree on addr/len, and then walk the list of items at
> that address linearly using your read/write() approach.
> 
> 
> > - add a small cache that can be scanned first
> >   
> 
> Yep, I think we may want to do this anyway independent of the search alg.
> 
> > In both cases, you first do a fast lookup, ask the device whether
> > it wants the transaction, then resort to linear scan if not
> >   
> 
> -Greg
> 

Looks like we have a concensus then.

-- 
MST
--
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/