Prev: printk.c: remove duplicate const
Next: [PATCH] fs-writeback.c: bitfields should be unsigned
From: Chris Wright on 1 Apr 2010 21:30
Hit another kdump problem as reported by Neil Horman. When initializaing
the IOMMU, we attach devices to their domains before the IOMMU is
fully (re)initialized. Attaching a device will issue some important
invalidations. In the context of the newly kexec'd kdump kernel, the
IOMMU may have stale cached data from the original kernel. Because we
do the attach too early, the invalidation commands are placed in the new
command buffer before the IOMMU is updated w/ that buffer. This leaves
the stale entries in the kdump context and can renders device unusable.
Simply enable the IOMMU before we do the attach.

Cc: Neil Horman <nhorman(a)tuxdriver.com>
Cc: Vivek Goyal <vgoyal(a)redhat.com>
Signed-off-by: Chris Wright <chrisw(a)sous-sol.org>
---
arch/x86/kernel/amd_iommu_init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -1288,6 +1288,8 @@ static int __init amd_iommu_init(void)
if (ret)
goto free;

+ enable_iommus();
+
if (iommu_pass_through)
ret = amd_iommu_init_passthrough();
else
@@ -1300,8 +1302,6 @@ static int __init amd_iommu_init(void)

amd_iommu_init_notifier();

- enable_iommus();
-
if (iommu_pass_through)
goto out;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: printk.c: remove duplicate const
Next: [PATCH] fs-writeback.c: bitfields should be unsigned