From mboxrd@z Thu Jan 1 00:00:00 1970 From: Don Slutz Subject: Re: Stubdom breakage in 4.5 Date: Wed, 04 Feb 2015 16:42:20 -0500 Message-ID: <54D2923C.2010204@terremark.com> References: <20150203122226.GB20260@zion.uk.xensource.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0257E12B5@AMSPEX01CL01.citrite.net> <1422971272.9323.92.camel@citrix.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0257E13AD@AMSPEX01CL01.citrite.net> <1423053001.17711.41.camel@citrix.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0257E22AE@AMSPEX01CL01.citrite.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9AAE0902D5BC7E449B7C8E4E778ABCD0257E22AE@AMSPEX01CL01.citrite.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Paul Durrant , Ian Campbell Cc: Wei Liu , Andrew Cooper , "xen-devel@lists.xen.org" , Stefano Stabellini , Jan Beulich , Ian Jackson List-Id: xen-devel@lists.xenproject.org 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@lists.xen.org; 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@lists.xen.org > http://lists.xen.org/xen-devel >