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From: Joerg Roedel <joro@8bytes.org>
To: Bernhard Walle <bernhard@bwalle.de>
Cc: nhorman@redhat.com, nhorman@tuxdriver.com,
	Joerg Roedel <joerg.roedel@amd.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Chris Wright <chrisw@sous-sol.org>,
	hbabu@us.ibm.com, iommu@lists.linux-foundation.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	vgoyal@redhat.com
Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash"
Date: Sun, 4 Apr 2010 10:53:38 +0200	[thread overview]
Message-ID: <20100404085338.GU24846@8bytes.org> (raw)
In-Reply-To: <4BB83EAE.5090609@bwalle.de>

On Sun, Apr 04, 2010 at 09:24:30AM +0200, Bernhard Walle wrote:
> Am 03.04.10 19:49, schrieb Eric W. Biederman:
> > Not a problem.  We require a lot of things of the kdump kernel,
> > and it is immediately apparent in a basic sanity test.
> 
> Also, in most cases (for example: distribution kernels), the kdump
> kernel nowadays is identical to the running kernel. So, if the running
> kernel has IOMMU support, the kdump kernel also has.

Yes, I know. But is that a requirement for kexec? If not we still
potentially have this problem. It is a smaller problem than
data-corruption caused by in-flight dma because most
people^Wdistributions indeed use the same kernel for normal boot and
kexec, thats true.

	Joerg


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Bernhard Walle <bernhard@bwalle.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	nhorman@redhat.com, nhorman@tuxdriver.com,
	Joerg Roedel <joerg.roedel@amd.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Chris Wright <chrisw@sous-sol.org>,
	hbabu@us.ibm.com, iommu@lists.linux-foundation.org,
	vgoyal@redhat.com
Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash"
Date: Sun, 4 Apr 2010 10:53:38 +0200	[thread overview]
Message-ID: <20100404085338.GU24846@8bytes.org> (raw)
In-Reply-To: <4BB83EAE.5090609@bwalle.de>

On Sun, Apr 04, 2010 at 09:24:30AM +0200, Bernhard Walle wrote:
> Am 03.04.10 19:49, schrieb Eric W. Biederman:
> > Not a problem.  We require a lot of things of the kdump kernel,
> > and it is immediately apparent in a basic sanity test.
> 
> Also, in most cases (for example: distribution kernels), the kdump
> kernel nowadays is identical to the running kernel. So, if the running
> kernel has IOMMU support, the kdump kernel also has.

Yes, I know. But is that a requirement for kexec? If not we still
potentially have this problem. It is a smaller problem than
data-corruption caused by in-flight dma because most
people^Wdistributions indeed use the same kernel for normal boot and
kexec, thats true.

	Joerg


  parent reply	other threads:[~2010-04-04  8:53 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-03  1:27 [PATCH 0/4] AMD IOMMU kdump fix plus cleanups (v2) Chris Wright
2010-04-03  1:27 ` Chris Wright
2010-04-03  1:27 ` [PATCH 1/4] x86/amd-iommu: enable iommu before attaching devices Chris Wright
2010-04-03  1:27   ` Chris Wright
2010-04-03  1:27 ` [PATCH 2/4] x86/amd-iommu: warn when issuing command to uninitialized cmd buffer Chris Wright
2010-04-03  1:27   ` Chris Wright
2010-04-03  1:27 ` [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash" Chris Wright
2010-04-03  1:27   ` Chris Wright
2010-04-03 17:22   ` Joerg Roedel
2010-04-03 17:22     ` Joerg Roedel
2010-04-03 17:44     ` Eric W. Biederman
2010-04-03 17:44       ` Eric W. Biederman
2010-04-04  8:44       ` Joerg Roedel
2010-04-04  8:44         ` Joerg Roedel
2010-04-04  9:16         ` Eric W. Biederman
2010-04-04  9:16           ` Eric W. Biederman
2010-04-04  9:19           ` Eric W. Biederman
2010-04-04  9:19             ` Eric W. Biederman
2010-04-03 17:41   ` Joerg Roedel
2010-04-03 17:41     ` Joerg Roedel
2010-04-03 17:49     ` Eric W. Biederman
2010-04-03 17:49       ` Eric W. Biederman
2010-04-03 19:13       ` Joerg Roedel
2010-04-03 19:13         ` Joerg Roedel
2010-04-03 19:41         ` Eric W. Biederman
2010-04-03 19:41           ` Eric W. Biederman
2010-04-04  7:24       ` Bernhard Walle
2010-04-04  7:24         ` Bernhard Walle
2010-04-04  7:51         ` Eric W. Biederman
2010-04-04  7:51           ` Eric W. Biederman
2010-04-04  8:53         ` Joerg Roedel [this message]
2010-04-04  8:53           ` Joerg Roedel
2010-04-04  9:44           ` Eric W. Biederman
2010-04-04  9:44             ` Eric W. Biederman
2010-04-04 10:01             ` Joerg Roedel
2010-04-04 10:01               ` Joerg Roedel
2010-04-06 17:42               ` Chris Wright
2010-04-06 17:42                 ` Chris Wright
2010-04-06 17:51                 ` Joerg Roedel
2010-04-06 17:51                   ` Joerg Roedel
2010-04-06 20:39                   ` Vivek Goyal
2010-04-06 20:39                     ` Vivek Goyal
2010-04-06 21:13                     ` Vivek Goyal
2010-04-06 21:13                       ` Vivek Goyal
2010-04-06 21:45                       ` Yinghai Lu
2010-04-06 21:45                         ` Yinghai Lu
2010-04-06 22:10                         ` Eric W. Biederman
2010-04-06 22:10                           ` Eric W. Biederman
2010-04-04 11:54     ` David Woodhouse
2010-04-04 11:54       ` David Woodhouse
2010-04-03  1:27 ` [PATCH 4/4] x86/amd-iommu: use for_each_pci_dev Chris Wright
2010-04-03  1:27   ` Chris Wright
2010-04-07 10:05 ` [PATCH 0/4] AMD IOMMU kdump fix plus cleanups (v2) Joerg Roedel
2010-04-07 10:05   ` Joerg Roedel

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