Bug 26160 - Add IOMMU_MMIO to dma protection flag
Summary: Add IOMMU_MMIO to dma protection flag
Status: NEW
Alias: None
Product: ANCK 6.6 Dev
Classification: ANCK
Component: X86 (show other bugs) X86
Version: 6.6.7-1
Hardware: x86_64 Linux
: P3-Medium S3-normal
Target Milestone: ---
Assignee: Guanjun
QA Contact: shuming
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-10-14 12:46 UTC by eastmouotain
Modified: 2025-10-14 13:51 UTC (History)
3 users (show)

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Description eastmouotain hygon_group 2025-10-14 12:46:25 UTC 
Description of problem:

If vaddr is mapped to PFN backend physical adress, add IOMMU_MMIO flag
to dma protection flag, so that IOMMU can do correct mapping, i.e. don't
set C bit in IO page table, otherwise the device can't recongnize the
phyiscal address with C bit set.

Version-Release number of selected component (if applicable):


How reproducible:
100%


Steps to Reproduce:
1. Create a SEV/CSV VM with two GPU card passthrough to the VM.
2. One GPU accesses the other GPU's MMIO memory region.


Actual results:
It fails to access the other GPU MMIO memory.


Expected results:
Access other GPU's mmio memory successfully.

Additional info:
Comment 1 小龙 admin 2025-10-14 13:51:19 UTC 
The PR Link: https://gitee.com/anolis/cloud-kernel/pulls/5854