* [PATCH] intel-iommu:make identity_map default for crash dump
@ 2011-10-21 12:31 Dave Young
2011-10-22 1:08 ` Simon Horman
0 siblings, 1 reply; 2+ messages in thread
From: Dave Young @ 2011-10-21 12:31 UTC (permalink / raw)
To: kexec, iommu, vgoyal, linux-kernel, luyu
kdump kernel sometimes will get DMAR faults which
is caused by random in-flight dma from 1st kernel
Here make the identity_mapping as default for this case
Signed-off-by: Dave Young <dyoung@redhat.com>
---
drivers/iommu/intel-iommu.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c621c98..8ac3895 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -40,6 +40,7 @@
#include <linux/tboot.h>
#include <linux/dmi.h>
#include <linux/pci-ats.h>
+#include <linux/crash_dump.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
@@ -2481,7 +2482,7 @@ static int __init init_dmars(void)
}
}
- if (iommu_pass_through)
+ if (iommu_pass_through || is_kdump_kernel())
iommu_identity_mapping |= IDENTMAP_ALL;
#ifdef CONFIG_DMAR_BROKEN_GFX_WA
--
1.7.4.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] intel-iommu:make identity_map default for crash dump
2011-10-21 12:31 [PATCH] intel-iommu:make identity_map default for crash dump Dave Young
@ 2011-10-22 1:08 ` Simon Horman
0 siblings, 0 replies; 2+ messages in thread
From: Simon Horman @ 2011-10-22 1:08 UTC (permalink / raw)
To: Dave Young; +Cc: kexec, iommu, vgoyal, linux-kernel, luyu
On Fri, Oct 21, 2011 at 08:31:54PM +0800, Dave Young wrote:
> kdump kernel sometimes will get DMAR faults which
> is caused by random in-flight dma from 1st kernel
>
> Here make the identity_mapping as default for this case
This seems reasonable to me. Although I am curious to know
what the side effects of using IDENTMAP_ALL might be.
^ permalink raw reply [flat|nested] 2+ messages in thread
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