CA-290024: Reject booting pv-iommu VMs on a host where the premap is yet to complete

[zli]

Signed-off-by: Zheng Li zheng.li3@citrix.com

[robhoes]

So this appears to just make the VM.start fail if pv-iommu is not yet ready, rather than causing the call to wait/block until it is ready. This may be the right thing to do, but the commit message is a little misleading.

[zli]

So this appears to just make the VM.start fail if pv-iommu is not yet ready, rather than causing the call to wait/block until it is ready.

Yes, this is to follow Bob's suggest on the ticket.

This may be the right thing to do, but the commit message is a little misleading.

Commit message is updated.

[lindig]

This iooks good. Just one suggestion.

[lindig]

I think this could be done simpler:

let is_ready =  
  try 
    let s = Unixext.string_of_file "/sys/kernel/pv_iommu_ready" in
    Scanf.sscanf s " %d " (fun d -> d=1)  
  with _ -> true

Note that this will scan strings like "1" or " 1" successfully.

[zli]

Updated with sscanf function suggested.
Though the mutable variable is_ready is on purpose, to avoid re-reading/re-parsing once it already becomes true.

[coveralls]

Coverage increased (+0.001%) to 20.921% when pulling 3120c88 on zli:CA-290024 into d59808f on xapi-project:master.