[PATCH] intel-iommu:make identity_map default for crash dump

[PATCH] intel-iommu:make identity_map default for crash dump

[Dave Young]

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


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

[PATCH] intel-iommu:make identity_map default for crash dump

[Dave Young]

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

Re: [PATCH] intel-iommu:make identity_map default for crash dump

[Simon Horman]

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.

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

Re: [PATCH] intel-iommu:make identity_map default for crash dump

[Simon Horman]

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.