Re: [PATCH] VT-d: IOTLB flush fixups

["Yang, Xiaowei" <xiaowei.yang@intel.com>]

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On Wed, 2008-05-28 at 23:00 +0800, Espen Skoglund wrote:

> Oh, right.  When flushing a non-present cached entry domid 0 must be
> used.  Here's a modification of your patch:
> 
>  - Made the non-present flush testing a bit simpler.
>  - Removed dma_addr_level_page_maddr().  Use a modified
>    addr_to_dma_page_maddr() instead.
Yes, it's simpler. Thanks! However, you forgot spin_unlock before
return. so it leads to deadlock. Here's a small fix.

>  - Upon mapping new context entry: flush old entry using domid 0 and
>    always flush iotlb.
Actually, you may find before/after your modification, the code are the
same functionally. We can pass domid=0 or non_present_entry_flush=1 to
flush non present tlb.

Thanks,
Xiaowei
> 


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diff -r f681c4de91fc xen/drivers/passthrough/vtd/iommu.c
--- a/xen/drivers/passthrough/vtd/iommu.c	Wed May 28 16:14:10 2008 +0100
+++ b/xen/drivers/passthrough/vtd/iommu.c	Thu May 29 03:48:33 2008 +0800
@@ -212,10 +212,10 @@ static u64 addr_to_dma_page_maddr(struct
     if ( hd->pgd_maddr == 0 )
     {
         if ( !alloc )
-            return 0;
+            goto out;
         hd->pgd_maddr = alloc_pgtable_maddr();
         if ( hd->pgd_maddr == 0 )
-            return 0;
+            goto out;
     }
 
     parent = (struct dma_pte *)map_vtd_domain_page(hd->pgd_maddr);
@@ -263,6 +263,7 @@ static u64 addr_to_dma_page_maddr(struct
     }
 
     unmap_vtd_domain_page(parent);
+ out:
     spin_unlock_irqrestore(&hd->mapping_lock, flags);
     return pte_maddr;
 }

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