Re: [Xen-devel] [Patch RFC 00/13] VT-d Asynchronous Device-TLB Flush for ATS Device

["Xu, Quan" <quan.xu@xxxxxxxxx>]

Thanks Jan.

>> >>> On 21.09.15 at 16:51, < JBeulich@xxxxxxxx > wrote:
>>> On 17.09.15 at 05:26, <quan.xu@xxxxxxxxx> wrote:
> Much more information:
>    If I run a service in this domain and tested this waitqueue case. 
> The domain is still working after 60s, but It prints out Call Trace with 
> $dmesg:
> 
> [  161.978599] BUG: soft lockup - CPU#0 stuck for 57s! 
> [kworker/0:1:272]

>Not sure what you meant to tell us with that (it clearly means there's a bug 
>somewhere in the series you're testing):
>- Drop the current series and wait for an update?

No.

>- A request for help? If so, I don't think there's much to be said
  based on just the kernel soft lockup detector output.
>- Anything else?


Just test the extreme case. The ATS specification mandates a timeout of 1 
_minute_ for cache flush, even though it doesn't take so much time for cache 
flush.
In my design, if the Device-TLB is not completed, the domain's vCPUs are not 
allowed entry guest mode (patch #7), otherwise, the logic is not correct.



~Quan


>Jan


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