[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Stubdom breakage in 4.5

On 02/04/15 07:58, Paul Durrant wrote:
>> -----Original Message-----
>> From: Ian Campbell
>> Sent: 04 February 2015 12:30
>> To: Paul Durrant
>> Cc: Wei Liu; xen-devel@xxxxxxxxxxxxx; Ian Jackson; Jan Beulich; Andrew
>> Cooper; Stefano Stabellini
>> Subject: Re: Stubdom breakage in 4.5
>> On Tue, 2015-02-03 at 14:11 +0000, Paul Durrant wrote:
>>> How about this as a slightly hacky solution that I think may work in both
>> cases?
>>> If Xen finds no emulator at all for an HVM guest then it waits around
>>> for at least one to show up before processing an emulation request.
>>> Until one does it stalls the vcpu in question indefinitely, but on the
>>> first emulator attach (i.e. ioreq server creations) then the IO will
>>> always be processed, even if it doesn't match the ioreq server.
>> It sounds plausible to me and seems like it would probably be
>> backportable.
> Actually I think it may be even simpler, although I've not tried it. If 
> hvm_domain_initialise() pauses the domain and the first 
> hvm_ioreq_server_enable() unpauses it, I'm hoping that may be enough.

You do need to keep the PVH case in mind here.

   -Don Slutz

>> Longer term I think we still need to fix the domain creation interlock
>> for launching multiple qemu's, ioreq servers and any other type of
>> service thing we might launch (whether in a stub dom or not), at which
>> point we may be able to remove the above workaround too.
> Yes. Once the toolstack is aware it can keep the domain paused until all 
> emulators report readiness.
>   Paul
>> Ian.
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.