Public bug reported:

See
https://canonical.lightning.force.com/lightning/r/Case/5004K000009WBzrQAG/view
for more info

[Impact]
Using nvme hardware that uses swiotlb in confidential VMs can encounter 
hardware read/write errors.


[Fix]

The following upstream patches address this:

3d2d861eb03e nvme-pci: set min_align_mask
1f221a0d0dbf swiotlb: respect min_align_mask
16fc3cef33a0 swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single
26a7e094783d swiotlb: refactor swiotlb_tbl_map_single
ca10d0f8e530 swiotlb: clean up swiotlb_tbl_unmap_single
c32a77fd1878 swiotlb: factor out a nr_slots helper
c7fbeca757fe swiotlb: factor out an io_tlb_offset helper
b5d7ccb7aac3 swiotlb: add a IO_TLB_SIZE define


[Test]

Using a confidential VM, with 'swiotlb=force' set on the kernel command
line, and an additional swiotlb nvme device attached:

$ sudo mkfs.xfs -f /dev/nvme2n1                                
meta-data=/dev/nvme2n1           isize=512    agcount=4, agsize=131072 blks     
         =                       sectsz=512   attr=2, projid32bit=1             
         =                       crc=1        finobt=1, sparse=0, rmapbt=0, refl
ink=0                                                                           
data     =                       bsize=4096   blocks=524288, imaxpct=25         
         =                       sunit=0      swidth=0 blks                     
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1                
log      =internal log           bsize=4096   blocks=2560, version=2            
         =                       sectsz=512   sunit=0 blks, lazy-count=1        
realtime =none                   extsz=4096   blocks=0, rtextents=0             
mkfs.xfs: pwrite failed: Input/output error


Note the input/output error

The error no longer happens with the fixes applied.

[Regression Potential]

** Affects: linux-oracle (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1943902

Title:
  NVME errors in confidential vms

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