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SubjectRE: [PATCH] Fix bug in iommu_context_addr: Always get pointer to lower extended-context-table
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Hi Joerg,

In commit message:

> There is a bug in iommu_context_addr() which will always use the lower context table, event when the upper context table needs to be used. Fix this issue.

I think it should be " even when the upper context table ", not "event".

Thanks!

Best Regards
Nan Xiao

-----Original Message-----
From: joro@8bytes.org [mailto:joro@8bytes.org]
Sent: Tuesday, August 25, 2015 5:00 PM
To: Xiao, Nan (Nan@HPservers-Core-OE-PSC)
Cc: dwmw2@infradead.org; iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix bug in iommu_context_addr: Always get pointer to lower extended-context-table

On Tue, Aug 25, 2015 at 08:46:27AM +0000, Xiao, Nan (Nan@HPservers-Core-OE-PSC) wrote:
> Yes, your patch is simple and better!

Okay, I queued this patch to my x86/vt-d branch:

From 03932776424a799c3f065a69e98076a78530288b Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Tue, 25 Aug 2015 10:54:28 +0200
Subject: [PATCH] iommu/vt-d: Really use upper context table when necessary

There is a bug in iommu_context_addr() which will always use the lower context table, event when the upper context table needs to be used. Fix this issue.

Fixes: 03ecc32c5274 ("iommu/vt-d: support extended root and context entries")
Reported-by: Xiao, Nan <nan.xiao@hp.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/intel-iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a85077d..63daf1b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -803,6 +803,7 @@ static inline struct context_entry *iommu_context_addr(struct intel_iommu *iommu
struct context_entry *context;
u64 *entry;

+ entry = &root->lo;
if (ecs_enabled(iommu)) {
if (devfn >= 0x80) {
devfn -= 0x80;
@@ -810,7 +811,6 @@ static inline struct context_entry *iommu_context_addr(struct intel_iommu *iommu
}
devfn *= 2;
}
- entry = &root->lo;
if (*entry & 1)
context = phys_to_virt(*entry & VTD_PAGE_MASK);
else {
--
1.8.4.5


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