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From: Vivek Goyal <vgoyal@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>,
	Neil Horman <nhorman@redhat.com>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	Simon Horman <horms@verge.net.au>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	linux-driver@qlogic.com,
	Andrew Vasquez <andrew.vasquez@qlogic.com>
Subject: Re: In place kexec
Date: Fri, 30 Jul 2010 14:56:25 -0400	[thread overview]
Message-ID: <20100730185625.GD3332@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1007301948420.13729@dwoodhou-mobl2.ger.corp.intel.com>

On Fri, Jul 30, 2010 at 07:50:19PM +0100, David Woodhouse wrote:
> On Fri, 30 Jul 2010, Vivek Goyal wrote:
> 
> >On Fri, Jul 30, 2010 at 11:21:42AM -0700, Eric W. Biederman wrote:
> >>David Woodhouse <dwmw2@infradead.org> writes:
> >>
> >>>On Thu, 2010-07-29 at 21:41 -0700, Eric W. Biederman wrote:
> >>>>There isn't a bus master shut off at the core level.
> >>>
> >>>Effectively, there is if you have an IOMMU.
> >>
> >>Depends on the IOMMU.  There are several dinky IOMMUs that when you
> >>shut them off DMA simply goes around them, and is not stopped.
> >
> >I think last time we were discussing this for AMD IOMMU where if you
> >disable IOMMU, it just kind of become pass through with 1:1 mapping of
> >addresses.
> 
> Yeah, don't do that. The IOMMU should be *on*, but without any
> active mappings set up. Which is exactly how Linux will set it up at
> boot.
> 

So what happens if we tear down the mapping while DMA is on.

Vivek

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  reply	other threads:[~2010-07-30 18:56 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-28 21:57 In place kexec H. Peter Anvin
2010-07-28 22:02 ` Eric W. Biederman
2010-07-29 13:43   ` Neil Horman
2010-07-29 15:03     ` H. Peter Anvin
2010-07-29 15:06       ` Neil Horman
2010-07-29 17:51         ` H. Peter Anvin
2010-07-29 18:06           ` Eric W. Biederman
2010-07-29 18:29             ` H. Peter Anvin
2010-07-29 19:16               ` Vivek Goyal
2010-07-29 19:51                 ` Eric W. Biederman
2010-07-29 19:55                   ` Randy Dunlap
2010-07-30  3:38                     ` H. Peter Anvin
2010-07-30  4:41                       ` Eric W. Biederman
2010-07-30  5:04                         ` H. Peter Anvin
2010-07-30 16:30                           ` Eric W. Biederman
2010-07-30 16:41                             ` H. Peter Anvin
2010-07-30 18:36                               ` Eric W. Biederman
2010-07-30 22:52                                 ` Andrew Vasquez
2010-07-30 23:25                                   ` H. Peter Anvin
2010-07-30 23:40                                     ` Eric W. Biederman
2010-07-30 16:53                         ` David Woodhouse
2010-07-30 18:21                           ` Eric W. Biederman
2010-07-30 18:34                             ` Vivek Goyal
2010-07-30 18:50                               ` David Woodhouse
2010-07-30 18:56                                 ` Vivek Goyal [this message]
2010-07-30 19:17                                   ` David Woodhouse
2010-07-30 19:39                                     ` Eric W. Biederman
2010-07-30 19:46                                       ` David Woodhouse
2010-07-30 20:08                                         ` Eric W. Biederman
2010-07-30 20:15                                           ` David Woodhouse
2010-07-30 21:11                                             ` H. Peter Anvin
2010-07-30 20:42                           ` H. Peter Anvin
2010-07-30 21:18                             ` Khalid Aziz
2010-07-30 21:44                               ` Khalid Aziz
     [not found]                                 ` <20120425211512.GA8583@ldl.usa.hp.com>
2012-04-25 22:06                                   ` Vivek Goyal
2010-07-29 20:06                   ` H. Peter Anvin

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