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From: Joerg Roedel <joro@8bytes.org>
To: Chris Wright <chrisw@sous-sol.org>
Cc: nhorman@redhat.com, nhorman@tuxdriver.com,
	Joerg Roedel <joerg.roedel@amd.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	hbabu@us.ibm.com, iommu@lists.linux-foundation.org,
	ebiederm@xmission.com, vgoyal@redhat.com
Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash"
Date: Sat, 3 Apr 2010 19:22:24 +0200	[thread overview]
Message-ID: <20100403172224.GO24846@8bytes.org> (raw)
In-Reply-To: <20100403012820.229410717@sous-sol.org>

On Fri, Apr 02, 2010 at 06:27:54PM -0700, Chris Wright wrote:
> This effectively reverts commit 61d047be99757fd9b0af900d7abce9a13a337488.
> 
> Disabling the IOMMU can potetially allow DMA transactions to
> complete without being translated.  Leave it enabled, and allow
> crash kernel to do the IOMMU reinitialization properly.
> 
> Cc: Joerg Roedel <joerg.roedel@amd.com>
> Cc: Eric Biederman <ebiederm@xmission.com>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
> ---
>  arch/x86/kernel/crash.c |    6 ------
>  1 file changed, 6 deletions(-)
> 
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -27,7 +27,6 @@
>  #include <asm/cpu.h>
>  #include <asm/reboot.h>
>  #include <asm/virtext.h>
> -#include <asm/x86_init.h>
>  
>  #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
>  
> @@ -103,10 +102,5 @@ void native_machine_crash_shutdown(struc
>  #ifdef CONFIG_HPET_TIMER
>  	hpet_disable();
>  #endif
> -
> -#ifdef CONFIG_X86_64
> -	x86_platform.iommu_shutdown();
> -#endif
> -
>  	crash_save_cpu(regs, safe_smp_processor_id());

Hmm, I think for this we need to change the gart code too and disable
the gart before its initialization runs to not re-introduce issues fixed
in commit bc2cea6a34fdb30f118ec75db39a46a191870607, no?

	Joerg


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WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Chris Wright <chrisw@sous-sol.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>,
	nhorman@redhat.com, nhorman@tuxdriver.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	hbabu@us.ibm.com, iommu@lists.linux-foundation.org,
	ebiederm@xmission.com, vgoyal@redhat.com
Subject: Re: [PATCH 3/4] Revert "x86: disable IOMMUs on kernel crash"
Date: Sat, 3 Apr 2010 19:22:24 +0200	[thread overview]
Message-ID: <20100403172224.GO24846@8bytes.org> (raw)
In-Reply-To: <20100403012820.229410717@sous-sol.org>

On Fri, Apr 02, 2010 at 06:27:54PM -0700, Chris Wright wrote:
> This effectively reverts commit 61d047be99757fd9b0af900d7abce9a13a337488.
> 
> Disabling the IOMMU can potetially allow DMA transactions to
> complete without being translated.  Leave it enabled, and allow
> crash kernel to do the IOMMU reinitialization properly.
> 
> Cc: Joerg Roedel <joerg.roedel@amd.com>
> Cc: Eric Biederman <ebiederm@xmission.com>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
> ---
>  arch/x86/kernel/crash.c |    6 ------
>  1 file changed, 6 deletions(-)
> 
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -27,7 +27,6 @@
>  #include <asm/cpu.h>
>  #include <asm/reboot.h>
>  #include <asm/virtext.h>
> -#include <asm/x86_init.h>
>  
>  #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
>  
> @@ -103,10 +102,5 @@ void native_machine_crash_shutdown(struc
>  #ifdef CONFIG_HPET_TIMER
>  	hpet_disable();
>  #endif
> -
> -#ifdef CONFIG_X86_64
> -	x86_platform.iommu_shutdown();
> -#endif
> -
>  	crash_save_cpu(regs, safe_smp_processor_id());

Hmm, I think for this we need to change the gart code too and disable
the gart before its initialization runs to not re-introduce issues fixed
in commit bc2cea6a34fdb30f118ec75db39a46a191870607, no?

	Joerg


  reply	other threads:[~2010-04-03 17:22 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 [this message]
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
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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