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

[Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>]

[Xiaowei Yang]
>> On map: only flush when old PTE was valid or invalid PTE may be cached.
>> On unmap: always flush old entry, but skip flush for unaffected IOMMUs.
>> 
>> Signed-off-by: Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>
>> 
>> --
>>  iommu.c |   17 +++++++++++------
>>  1 file changed, 11 insertions(+), 6 deletions(-)
>> --
>
> Seems my last mail sent to the xen-devel is lost and I have no local
> copy so I have to write again...
>
> Espen,
> Thanks for the patch! I also noticed context/iotlb flush need a
> cleanup.  As flush of present/non-present entry are different, your
> change to iommu_intel_map_page are not that correct. So I made up
> anther patch.  iommu_flush is also removed, as VTd table is not
> shared with p2m any more.
>
> Signed-off-by: Xiaowei Yang <xiaowei.yang@xxxxxxxxx>

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.
 - Upon mapping new context entry: flush old entry using domid 0 and
   always flush iotlb.

Signed-off-by: Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>

--
 arch/x86/mm/hap/p2m-ept.c       |    6 -
 drivers/passthrough/vtd/iommu.c |  150 ++++++++++------------------------------
 include/xen/iommu.h             |    1 
 3 files changed, 38 insertions(+), 119 deletions(-)

Attachment: xen-vtd-flush.patch
Description: Binary data

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